SURGICAL PATHOLOGY Liver: Non-neoplastic Conditions August 17, 2010 VIRAL HEPATITIS ACUTE HEPATITIS Definition Acute infection by hepatotropic viruses A, B, C, D. The necrosis can be spotty, bridging or submassive. Clinical features Severe and very severe necrotizing hepatitis: o uncommon o clinically fulminant hepatitis with: acute liver failure coma Pathogenesis Acute Viral Hepatitis B Liver cell damage apparently caused by T cell-mediated and humoral mechanisms1 Thought to be an ‘elimination type’ of disease: o i.e. virus eradication ensures self- limited course2 Histopathology Appearance due to different hepatitis viruses may be similar Varying severity: o mild o moderate: o severe o fatal Lesions involve: o lobular parenchyma o portal tracts Typical Acute Viral Hepatitis Spotty necrosis Panlobular Changes may predominate in: o centrilobular region in hepatitis B and C o periportal zone in hepatitis A Hepatocellular alterations variable Some parenchymal cells: o show: ballooning (Fig. 1 ) Fig. 1: Acute viral hepatitis B. Centrilobular area of liver lobule, characterized by liver cell pleomorphism (including ballooning of hepatocytes), some canalicular bilirubin stasis, focal liver cell loss, and mononuclear (mainly lymphocytic) inflammatory infiltration. (H&E) increased cell volume pale-staining, granular cytoplasm: i.e. hydropic change o probably precursor stages of lytic necrosis or cell dropout Other hepatocytes: o show: shrinkage increased eosinophilia nuclear pyknosis o most represent cells in process of apoptosis3,4 o may appear as: condensed shrunken cell clusters of cell fragments: may contain pyknotic nuclear material o often described as: acidophil bodies Councilman bodies (incorrect term) o may be: naked in close proximity to mononuclear inflammatory cells (Fig. 2 )
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o centrilobular region in hepatitis B and Co periportal zone in hepatitis A
Hepatocellular alterations variable Some parenchymal cells:
o show: ballooning (Fig. 1)
Fig. 1: Acute viral hepatitis B. Centrilobular area of liver lobule, characterized by liver cell pleomorphism (including ballooning of hepatocytes), some canalicular bilirubin stasis, focal liver cell loss, and mononuclear (mainly lymphocytic) inflammatory infiltration. (H&E)
i.e. hydropic changeo probably precursor stages of lytic necrosis or cell
dropout Other hepatocytes:
o show: shrinkage increased eosinophilia nuclear pyknosis
o most represent cells in process of apoptosis3,4o may appear as:
condensed shrunken cell clusters of cell fragments:
may contain pyknotic nuclear material
o often described as: acidophil bodies Councilman bodies (incorrect term)
o may be: naked in close proximity to mononuclear
inflammatory cells (Fig. 2)
Fig. 2: Detail of lobular parenchyma in mild acute viral hepatitis C. Eosinophil condensation of hepatocellular cytoplasm (Mallory body-like) and rounded eosinophil fragments of apoptotic hepatocyte, with a few adjacent mononuclear inflammatory cells. (H&E)
usually within portal connective tissue, with preservation of limiting plate
sometimes spills out into adjacent parenchyma:
blurs outline of portal tract resembles piecemeal necrosis or
interface hepatitis characteristic of chronic hepatitis
Acute Hepatitis Increase in ductular profiles at portal–parenchymal interface:
o so-called ductular reactiono very mild in classical acute lobular hepatitiso better revealed by cytokeratin 7 immunostainso extent increases with severity of necrotizing
parenchymal lesions May be:
o lymphocytic infiltration between and inside bile duct lining cells
o some bile duct epithelial damage:o especially in viral hepatitis C7
Later Stages Of Acute, Self-Limited Hepatitis Most parenchymal and portal changes gradually disappear Residual changes:
o such as: mild infiltration in some portal tracts some focal inflammation in lobules a few remaining macrophages anisokaryosis too prominent for patient's
ageo may persist for several months
Minimal Acute Hepatitis Limited damage and inflammation Slight liver cell ballooning Some apoptotic bodies No bilirubin stasis Mild lymphocytic infiltrate Scant numbers of macrophages Minimal infiltration in only part of portal areas
Severe Acute Hepatitis Acute hepatitis with bridging necrosis Death of larger groups of hepatocytes More extensive parenchymal damage:
o usually lytic necrosis of hepatocytes affecting contiguous parenchymal territories:
i.e. confluent necrosis predominantly in microcirculatory
periphery Patterns of necrosis best explained according to acinar concept of
liver architecture:8o with increasing severity, confluent necrosis wipes out
parenchyma of periphery of acinar zone 3: results in centrilobular confluent necrosis
o a higher degree involves entire acinar zone 3: results in dropout of parenchyma between
portal tracts and central veins: i.e. bridging hepatic necrosis:
Fig. 3: Severe necrotizing acute viral hepatitis B. Overview of liver lobule; mild to moderate mononuclear cell infiltration in portal tracts (lower left, top, and lower right). Bridging portal–central confluent lytic necrosis, realizing a ‘star-shaped’ area of necrosis with a centrilobular vein at its center and peripheral points reaching portal tracts. Inflammatory cells are scattered throughout the lobule. (H&E)
)o even higher degree of severity;
lytic necrosis of all acinar zones: i.e. panlobular and multilobular
necrosis
Necrotic Bridges Change in appearance over time:
o if new: reveal lobular areas where parenchyma has
disappeared, without or little collapse of reticulin framework
necrotizing areas infiltrated by: mononuclear cells some small ceroid macrophages
o later stages: collapse of reticulin fibers proliferation of mesenchymal cells collagen deposition possibly:
bulging of regenerating remaining parenchyma
larger numbers of ceroid macrophages
o older necrotic bridges: heal with fibrous scars:
result in portal–central bridging fibrosis
o severely necrotizing hepatitis:
more severe periportal ductular reaction areas of surviving parenchyma:
changes of classical lobular hepatitis but:
usually more marked: focal
necrosis bilirubin
stasis
Acute Hepatitis With Panlobular And Multilobular Necrosis Submassive liver necrosis Severe and very severe necrotizing hepatitis Parenchyma:
o lytic confluent necrosis: throughout entire liver lobule:
i.e. panlobular necrosis affects several adjacent lobules:
i.e. multilobular necrosis: if survive results in
alternating: collapse
and fibrous scarring of necrotic zones
nodular regeneration of surviving parenchymal territories
o extensive confluent necrosis usually distributed heterogeneously throughout liver:
needle biopsies may not be representative Ductular reaction:
o more prominent in multilobular necrosiso represents attempt at regeneration by liver progenitor
cellso corresponds to ‘atypical’ ductular reaction:
i.e. epithelial proliferation comprises: bile ductular cells transitional cells with phenotype
intermediate between cholangiocytes and hepatocytes11,12
o if severe necrosis or sepsis: some ductules may contain inspissated
bilirubin-stained concrements:13 should not be mistaken as sign
of biliary obstruction
Special Stains and ImmunohistochemistryAcute Viral Hepatitis A14–17
Immunohistochemistry: o viral antigen in cytoplasm of:
hepatocytes Kupffer cells18
Viral RNA located by in situ hybridization19
DiagnosisAcute Viral Hepatitis
Histology: o similar for acute viral hepatitis A, B, C, D, and Eo may be confused by:
Chronic Viral Hepatitis B Successive phases of viral replication, elimination, and integration,
associated successively with:
o lesser, higher, and again decreasing degrees of necroinflammatory disease activity5,6
o implies successive occurrence of CPH and CAH variants in individual patients
Chronic Hepatitis C Hepatocellular damage mainly immune mediated7
Factors Associated With Fibrosis Strength of association varies Include:
o male gendero advanced ageo excessive alcohol useo duration of infectiono HIV coinfection8–10o nonalcoholic steatohepatitis11o porphyria cutanea tarda12
o apoptosiso genuine necrosis of single hepatocytes
More appropriate term would be focal necroinflammation: o recognizable as:
small cluster of mononuclear cells: lymphocytes possibly histiocytes
may be adjacent identifiable apoptotic body or bodies
Looks the same as in acute hepatitis (Fig. 1)
Fig. 1: Acute viral hepatitis B. Centrilobular area of liver lobule, characterized by liver cell pleomorphism (including ballooning of hepatocytes), some canalicular bilirubin stasis, focal liver cell loss, and mononuclear (mainly lymphocytic) inflammatory infiltration. (H&E)
Confluent Lytic Necrosis More severe disease14 Dropout of contiguous groups of hepatocytes with denudation of
Extent may range from focal and zonal over ‘bridging’ confluent necrosis (Fig. 2)
Fig. 2: Bridging confluent lytic necrosis in severe chronic viral hepatitis B. Inflamed portal tract ‘bridged’ through area of necrosis with centrilobular area (lower left). The upper right part corresponds to an area of extensive lytic necrosis in phase of postnecrotic collapse of the reticulin framework and early fibrosis. (H&E) to more extensive panlobular and multilobular
Often small, glandlike clusters of surviving hepatocytes – hepatitic rosettes – within inflamed tissue (Fig. 3):
Fig. 3: Severe chronic viral hepatitis B. Area of multilobular lytic necrosis in phase of postnecrotic collapse and early fibrosis, with several small islands of surviving hepatocytes, appearing swollen and pale, and sometimes arranged in tubular fashion (‘hepatitic-type liver cell rosettes’). (H&E)
o usually surrounded by connective tissueo presumably attempts at regeneration from surviving
hepatocytes
Portal Inflammation May be:
o mildo moderateo dense
Composed of: o mononuclear cells:
mainly lymphocyteso variable numbers of plasma cellso other mononuclear cells:
histiocytes immature lymphocytes
May be: o lymphoid aggregateso true lymphoid follicles
Interface Hepatitis Originally termed ‘piecemeal necrosis’ (Fig. 4)
Fig. 4: Marked interface hepatitis (‘piecemeal necrosis’) in chronic viral hepatitis B. Note inflamed portal tract (upper right) and wedgelike extension of necroinflammation (towards lower left) and irregular interface between portal periphery and adjacent parenchyma all around the necroinflammatory area.
Interface hepatitis preferred terminology because: o mode of liver cell death is apoptosis, not necrosis15–
17o lesion is at interface between:
mesenchyme (portal tract or septum) parenchyma
Periportal18 Corresponds to extension of lymphocytic portal infiltrate beyond
limits of portal tract Associated with cell death (cell by cell or ‘piecemeal’) of
hepatocytes Surviving hepatocytes trapped within inflammatory infiltrate Neoangiogenesis Fibrosis May be:
o mild: one or a few foci around portal perimeter
without noticeable fibrous extensiono severe:
wedge-shaped extension of necroinflammatory lesion
obvious fibrosis deep into lobule Causes enlargement of portal tracts with irregular outlines
Fibrosis Progressive in more active variants Intralobular fibrosis:
o apparently due to continuous ongoing lobular necroinflammatory damage19
Septal fibrosis: o may be:
periportal: presumably result of interface
hepatitis portal–portal:
presumably result of interface hepatitis
portal–central septa: apparently result of portal–
central (bridging) confluent necrosis
Cirrhosis Result of:
o ongoing necroinflammationo progressive fibrosiso parenchymal regeneration
o finely granular and more pale appearance of part or all cytoplasm – ‘ground glass’ area:
often separated from cell membrane by clear halo – an artefact (Fig. 5)
Fig. 5: Chronic viral hepatitis B, high magnification. Ground glass hepatocytes, characterized by more pale, eosinophilic, and homogeneous cytoplasm than surrounding normal (more granular) hepatocytes. Note (artefactual) cleft between ‘ground glass’ cytoplasm and hepatocellular cell membrane. The first nucleated hepatocyte in the left lower corner reveals a less pronounced ‘ground glass’ appearance (corresponding to less extensive endoplasmic reticulum hyperplasia and less massive accumulation of HBsAg). (H&E)
due to marked hypertrophy of smooth endoplasmic reticulum:
displaces cytoplasmic organelles to periphery of cell
contains excess filamentous structures of HBsAg in cisternae:21,22
HBsAg relationship confirmed by special stains, such as:
Shikata's orcein stain23
Victoria blue24
aldehyde fuchsin25
specific antibody
not entirely specific: occurs in other liver
diseases26–32
Sanded Nuclei Larger central part of nucleus:
o finely granularo pale eosinophilic:33
due to massive accumulation of HbcAg not easily recognized specific immunohistochemistry helpful in
identifying HBcAg
Findings During Course Of Disease Vary
Early Viral Replication And Immune Tolerance Phase Minimal hepatocellular damage and inflammation HbcAg37 and HbeAg in:38
o nucleuso cytoplasmo liver cell membranes (Fig. 6)
Fig. 6: Chronic viral hepatitis B; viral replicative phase. Hepatitis B core antigen is localized in hepatocellular nuclei and, in several hepatocytes; also in the cytoplasm and cell membrane. (Immunoperoxidase stain for HBcAg)
HbsAg in: o cytoplasm of some scattered hepatocyteso membrane of numerous parenchymal cells:
Fig. 7: Chronic viral hepatitis B: viral replicative phase. Hepatitis B surface antigen is localized in variable quantity in the cytoplasm and in the cell membrane of several hepatocytes. Note only mild lymphocytic infiltrate in portal tract and lobule. (Immunoperoxidase stain for HBsAg)
Viral Elimination Phase Low viral replication Immune clearance of hepatocytes Seroconversion from HBeAg to HBe antibody Disappearance of HBV DNA from serum More necroinflammatory lesions:
o including confluent lytic necrosis in more severe cases42
HBcAg in: o nucleuso cytoplasmo liver cell membranes
HBeAg in: o nucleuso cytoplasm43
HbsAg: o weak positivity in cytoplasm of some hepatocytes with
membranous staining pattern:34,35,41 mild inflammation may persist for some
time after loss of HBsAg in serum44 After acute exacerbations45 cirrhotic changes in ≈40% of
patients:34o if cirrhosis does not supervene liver may recover with
only minimal histologic abnormalities46 Sometimes ongoing inflammatory activity and interface hepatitis:
o due to persistence of a special mutant of HBV with deficient HBeAg synthesis47,48
o immunostaining reveals cytoplasmic HbcAg49
Phase Of Viral Integration Occurs when some virus-replicating hepatocytes apparently
escape immune elimination: o leads to:
persistence of viral infection integration of viral DNA into host genome:
HBsAg is continuously produced by these cells50
patient becomes HBsAg carrier HBsAg accumulates in clusters of
hepatocytes: appears as:
ground glass cells, or
staining in periphery of parenchymal cells (Fig. 8
Fig. 8: Chronic viral hepatitis B: viral nonreplicative (integration) phase. Hepatitis B surface antigen is localized in considerable quantity in the cytoplasm of a contiguous group (‘clone’) of hepatocytes. Note relatively mild lymphocytic infiltrate in portal tract and lobule. The more intensely staining cells appear as ‘ground glass hepatocytes’ on H&E staining. (Immunoperoxidase stain for HBsAg)
HBcAg usually absent No active replication of HBV More aggressive forms of disease41 and cirrhosis46 more likely if:
o persistent HBcAg in livero higher level of HBV viremia
May be: o normal architectureo variable degrees of fibrosiso cirrhosis:
progresses slowly over 20–30 years eventually decompensation and other
complications initially micronodular later more macronodular34 may be complicating hepatocellular
carcinoma: Healthy HBsAg carriers:
o no cirrhosiso risk for hepatocellular carcinoma
May be precancerous lesions in precirrhotic and cirrhotic stages: o large cell dysplasiao small cell dysplasiao macroregenerative nodules
Chronic Viral Hepatitis B + D Compared with uncomplicated chronic hepatitis B chronic
hepatitis D tends to be: o more severe, with:
higher activity risk of progression51,52
Occasionally: o rapid progression to cirrhosis with active HBV
replication More commonly:
o slow disease evolutiono evolves into cirrhosis over many years53,54
HDV: o selectively suppresses HBcAg and HBeAg, but not
HbsAg55o depends on low-grade HBV multiplication and
release56 Immunohistochemically, HDAg found:
o mainly in liver cell nuclei:57 may show sanded appearance58 due to
o in cytoplasm and membranes of hepatocytes59 Double immunostaining for HBV and HDV antigens:
o often separate expression of HDAg versus HBsAg or HbcAg
o may be coexpression60
Chronic Viral Hepatitis C 170 million people with chronic infection worldwide61,62 Usually silent onset High rate of viral persistence Potential worsening chronic liver disease:
o chronic hepatitiso cirrhosiso occasionally hepatocellular carcinoma61
Retrospective studies tend to overestimate progression to cirrhosis and cancer
Prospective and cohort studies: o indicate lower rate of progressiono suggest spontaneous viral clearance may be higher
than thoughto severe, life-threatening, progressive liver disease in
perhaps 30% of those chronically infected Characteristic histopathology:63–66
o initially often mild with little parenchymal damage:67,68
o mainly focal inflammation and hepatocellular apoptosis69
o spontaneous exacerbations70o reactivation after immunosuppressive therapy71o relapse after interferon therapyo portal infiltrate rich in lymphocytes:
often lymphoid aggregates (Fig. 9)
Fig. 9: Chronic viral hepatitis C. Low-power view of two joined portal tracts with dense mononuclear cell infiltration, forming a lymphoid aggregate and a lymph follicle. The portal–parenchymal interface is irregular (moderate degree of interface hepatitis). A few scattered macrovesicular steatosis vacuoles are visible in the lobular parenchyma. (H&E)
even follicles: particularly prominent germinal
centers72–79 not specific for hepatitis C also in:
hepatitis B72,77 autoimmune
hepatitis72 primary biliary
cirrhosis Lesions of interlobular bile ducts (Fig. 10):
Fig. 10: Chronic viral hepatitis C. Detail of portal tract showing a lymph follicle containing an irregular and damaged bile duct near its center. Note the epithelial irregularity and intramural lymphocytic infiltrate. (H&E)
o in 15 to 91% of biopsies:65,72
i.e. poor consensus on definition of bile duct lesion
o most frequently observed lesion: infiltration of lymphocytes between
cholangiocytes bile duct lining cells show variable degrees
of: vacuolation stratification crowding
o most pronounced bile duct lesion:80 swelling and polystratification of bile duct
lining cells infiltration by lymphocytes and larger
mononuclear cells preservation of basement membrane81 differentiate from lesion in primary biliary
cirrhosis Lobular lesions:
o may comprise striking number of acidophil bodies (apoptosis)
Mild to moderate steatosis (Fig. 11):
Fig. 11: Chronic viral hepatitis C: moderately dense portal infiltrate, focus of interface hepatitis; marked macro- and mediovesicular steatosis; occasional apoptotic body (middle left). (H&E)
o usually macrovesicularo in 1 to 72%65,72 of biopsieso appears to be mainly viral effect,82 especially of HCV
o may contain coarse clumps of eosinophilic cytoplasm: Mallory body-like77,84
Lymphocytic infiltration in lobules: o may form rows along sinusoids (Indian files):
resembles hepatic mononucleosis Venous lesions:
o resemble endotheliitis in cellular liver allograft rejection85
Epithelioid granulomas: o in 5% of cases86–88o apparently transient89o has been correlated with interferon-α therapy90o associated with good91 and bad response92o exclude other causes of granulomas87
Some bile duct loss in late (cirrhotic) stage:93o differentiate from primary biliary cirrhosis
Increased hepatic iron: o even in absence of blood transfusion or alcohol
abuse94o iron overload impairs response to interferon
therapy:95 liver biopsy assessment should include
comment about presence or absence of excess iron in hepatocytes96
Similar histopathology in children:97o perhaps faster development of fibrosis98
Different genotypes of HCV may influence histopathology, such as:
o degree of steatosiso rate of bile duct lesionso disease activity99,100
Increased inflammatory activity, especially interface hepatitis:101o if clinical manifestations of autoimmunity
Premalignant Lesions In Chronic Viral Hepatitis B and C Strong association between hepatocellular carcinoma and:
o chronic hepatitis B102o chronic hepatitis C103
Main presumed or proven premalignant lesions in chronic hepatitis type B and C:
o liver cell dysplasia: large and small cell types:104
dysplastic foci: groups of (large-cell
or small-cell) dysplastic hepatocytes <1mm diameter105
o macroregenerative nodules (adenomatous hyperplasia)106
increased May be a better precancerous candidate than large cell
dysplasia111
Macroregenerative Nodule Previously termed adenomatous hyperplasia Unusually large regenerative nodule ≥0.8cm diameter In cirrhosis and other chronic liver disease:
o particularly macronodular cirrhosis112,113 Dysplastic nodules:
o >1mmo considered to be more advanced precursor lesions105o low or high grade, with varying degrees of:
liver cell dysplasia increased cellularity loss of cohesiveness pseudoacini focal loss of reticulin fibers113,114
Autoimmune HepatitisHistopathology of chronic hepatitis
Suggestive features:101,115o necroinflammatory activity tends to be high in
Fig. 12: Chronic viral hepatitis C. Viral antigen (HCV-E2), appearing as positive cytoplasmic granules, is localized in virtually every periportal hepatocyte in this case. (Immunoperoxidase ‘Envision’ technique, using antibody IGH222 – Innogenetics, Ghent, Belgium119)
No accurate noninvasive markers of disease activity and fibrosis Liver biopsy:122,123
o exclude other liver pathologyo establish stage
Autoimmune Hepatitis Several types:
o different patterns of autoantibodies124 May benefit from immunosuppressive therapy
Drug-induced Chronic Hepatitis Always consider when etiology obscure
Cryptogenic Chronic Hepatitis No characteristic features pointing to a particular etiology Disease activity often mild125
Combined PathologyCombined Infection With HBV and HCV
Increases severity of histologic liver lesions126 Triple infection with HBV, HDV, and HCV:
o severe disease in acute superinfection stageo course:
relatively benign slowly progressive usually dominated by HCV127,128
Superinfection Of Chronic Hepatitis B with HDV Usually severe activity with extensive interface hepatitis33,43
HIV Infection Results in reactivation of hepatitis B:
o higher levels of HBV replicationo no increase in necroinflammationo more immunocytochemically demonstrable HBcAg and
HBeAg129 With chronic hepatitis C:
o higher necroinflammatory activityo cirrhosis more frequent130
HGV Virus Infection No apparent effect on chronic hepatitis C131,132
TTV Infection Reported not to affect course of chronic hepatitis B or C and
response to interferon-α therapy133
Multiple Hepatitis Virus Infection Quite common
Cannot be reliably recognized histologically134 Immunocytochemical stains for viral antigens helpful135
Hemochromatosis136 May be foci of hepatocellular hemosiderosis in chronic viral
hepatitis C and B
ClassificationOriginal Classification
Simple classification of chronic hepatitis, based on histology proposed in 1968:137
o immunosuppression was standard treatment reserved for the more ‘active’ forms
o distinguished between: milder form with low level
With Lobular Lesions Distinguish from acute hepatitis Orcein staining helps identify older collapse Ground glass hepatocytes testify to chronicity in hepatitis B Bilirubin stasis much more frequent in acute hepatitis
With Interface Hepatitis Primary biliary cirrhosis Primary sclerosing cholangitis Wilson's disease Alpha-1-antitrypsin deficiency Lymphoma Alertness, special stains, and coordination with clinical
information essential for correct diagnosis
Staging/gradingGrade of Disease Activity
Clinical symptoms Aminotransferase levels Histopathology of liver biopsy:
o main components: portal inflammation interface hepatitis intralobular damage and inflammation confluent necrosis
o several systems: daily practice:
an adequate report consists of accurate estimate of various lesions, described as:
minimal mild moderate severe
for specific purposes, such as comparison of pre- and post-treatment biopsy specimens and for evaluation of therapeutic trials:
semiquantitative scoring systems
Stage Of Disease Progression Evolutionary stage has significant prognostic and therapeutic
implications142 Histologic evaluation based on:
o extent of fibrosiso development of cirrhosis
Connective tissue stains are essential for staging Can be expressed in classical descriptions:
o appropriate method for daily reporting of biopsies For specific purposes, semiquantitative scoring systems
Semiquantitative Scoring Several systems proposed as applied in other areas of diagnostic
histopathology147–162 Histological Activity Index (HAI or Knodell index)
o published 1981158o most widely used
Simple scoring system proposed by Scheuer:162o easily applicable and reproducible154
Modified HAI: o extension of Knodell system, with modifications156o validated for intra- and interobserver variability163
Chronic hepatitis C system proposed by French METAVIR Cooperative Study Group:150,151
o widely applied, especially for staging164,165 Different scoring systems have different strengths and
weaknesses150,166–172 Histologic scoring:
o reserve for special purposes: comparing pre- and post-treatment biopsies
of a single patient as a research method for studying course of
disease as a tool in clinical therapeutic trials153
Choose most suitable system for: o grading173o staging174o use:
clinical practice investigative work166
Define criteria for each score as strictly as possible156,172 Scoring carried out by at least two observers152 Control intra- and interobserver variation:167
o accurate meta-analysis not possible172
Other systems A mathematical scoring system:
o based on fractal geometry for quantifying irregular pattern of liver fibrosis175
Morphometry173 and image-analysis quantification:177–179o appear more sensitive than semiquantitative scoring in
detecting smaller changes in degree of fibrosis Restricted to specialized centers Best used in combination with semiquantitative histologic
evaluation systems178
ManagementAutoimmune Hepatitis
Immunosuppressive treatment reduces severity of necroinflammation and fibrosis180
CIRRHOSISDefinitionDiffuse hepatic fibrosis and replacement of normal hepatic architecture by parenchymal nodules separated by fibrous tissue. The end stage of a variety of chronic liver disorders.
Clinical Features End stage of many chronic liver diseases
o replacement of normal lobular architecture by parenchymal nodules separated by fibrous tissue1
Portal–central septa linking portal tracts and central veins: o important component
Histologically best appreciated on reticulin stain2 Variable hepatocellular features of individual nodules such as:
o steatosiso siderosiso ground glass hepatocytes
Morphologic Classification Based on size of nodules1
o micronodular: nearly all nodules <3mm diameter (Fig. 1)
Fig. 1: Detail from micronodular cirrhosis. (Reticulin silver impregnation)
o macronodular: nearly all nodules >3mm diameter (Fig. 2)
Fig. 2: Detail from macronodular cirrhosis. Note larger nodules, thin, fibrous septa, and irregular orientation of liver cell plates. (Reticulin silver impregnation)
o mixed micro-macronodular:o ≈ equal numbers of nodules > and <3mm diameter
Needle Biopsy SpecimensMicronodular and Macronodular Cirrhosis
Nodular size determines ease with which diagnosis can be made Nodularity and septa may be readily evident in micronodular
cirrhosis More subtle criteria for macronodular cirrhosis including:
o fragmentation of biopsy specimen: especially with slender tissue cylinders
provided by thin aspiration type needleso thin layers of connective tissue adhering to rounded
edges of nodular biopsy fragmentso abnormal orientation of reticulin fibers due to different
rates of parenchymal growth in different areaso portal tracts and central veins:
abnormal spacing excess numbers of draining veins in relation
to number of portal tractso presence of minute and poorly formed portal tracts
(‘mini-portal tracts’)o hepatocellular features of regeneration:
double-cell plates over widespread areas different appearance of hepatocytes in
adjacent areas liver cell dysplasia:
large cell small cell
Incomplete Septal Cirrhosis Most difficult type to recognize (Fig. 3)
Fig. 3: Detail from ‘incomplete septal type’ cirrhosis. Can be considered a macronodular variety of cirrhosis with large multilobular nodules, thin, incomplete septa, and little inflammatory activity. (Sirius red stain)
Characterized by: o vague nodularityo slender septa:
some end blindlyo mini-portal tractso excess efferent veinso sinusoidal dilatation
Parenchymal hyperplasia with compression of reticulin fibers in adjacent areas
Absent or minimal: o inflammationo necrosis3
Histologic Activity Should be noted May reflect ongoing disease even in cirrhotic stage Activity consists of:
o various forms of liver cell damage and inflammation seen in precirrhotic stage e.g.:
interface hepatitis in posthepatitic cirrhosis steatohepatitis in cirrhotic alcoholics and
Histopathology virtually indistinguishable from acute viral hepatitis
Combines: o hepatocellular damage and death:
variable degreeo portal and parenchymal inflammation:
variable extent
Drug-induced Chronic Hepatitis Elementary lesions of chronic hepatitis in various stages, including
cirrhosis No specific histologic lesions
Drug-induced Steatohepatitis Resembles acute hepatitis of alcoholic type
Drug-induced Cholestatic Hepatitis Lesions of acute hepatitis with moderate or marked bilirubin
stasis May be prominent eosinophils in inflammatory infiltrate
Drug-induced Granulomatous Hepatitis Combines features of:
o usually mild hepatitiso noncaseating granulomas
If bilirubin stasis and infiltration of eosinophils, virtually diagnostic for drug-induced liver disease42
Special Stains and ImmunohistochemistryDrug-induced Chronic Hepatitis
Autoantibodies may cause confusion with autoimmune hepatitis43
Diagnosis Recognition difficult because:44
o may mimic any naturally occurring liver diseaseo occurs with compounds from all classes of
drugs2,45,46o may not be clinical signs of a hypersensitivity reactiono drug histories often not reliableo often impossible to pinpoint causative agent if on
multiple drug therapyo same drug may cause different patterns of liver
damage in different patients47o hepatotoxicity may not yet have been reported for a
particular drug, even after a long time on the marketo liver damaging effect may be accentuated by
concomitant administration of other pharmacologic agents
Specific sources of information include: o Books1,48o Reviews49–53
Always maintain high degree of suspicion:54o especially:
in elderly if on histopathology:
resembles viral hepatitis: with
disproportionately severe parenchymal necrosis in relation to clinical condition
associated: steatosis granuloma
s
infiltration by eosinophils
bile duct damage55
centrilobular necrosis sharply delineated from non-necrotic parenchyma, especially if:
associated steatosis only mild or minimal
inflammation numerous ceroid
macrophages55 parenchymal giant cell hepatitis
in adult hepatocyte necrosis with veno-
occlusive disease56
Drug-induced Chronic Hepatitis Diagnosis:
o important: may be cured by withdrawal of drug
o relies on: high degree of suspicion in absence of viral
markers close cooperation from clinician and patient
Drug-induced Granulomatous Hepatitis Virtually diagnostic for drug-induced liver disease if:
Bile Duct Damage And Ductopenia Differential diagnosis includes most vanishing bile duct diseases
Drug-induced Cholestatic Hepatitis Differentiation from bile duct obstruction relies on absence or low
expression of typical obstructive features such as: o portal edemao neutrophil-associated ductular proliferation
Severe liver cell damage and marked inflammation are more suggestive of:
o viral hepatitiso viral-like drug-induced acute hepatitis
STEATOSIS AND STEATOHEPATITISSTEATOSISDefinitionAccumulation of triglycerides in the hepatocytic cytoplasm, usually indicating reversible liver damage. Divided into macrosteatosis and microsteatosis, the latter being seen in life-threatening conditions such as Reye's syndrome.
Clinical Features Common Hepatomegaly May be elevated serum:
o aminotransferaseso alkaline phosphataseo γ-glutamyl transpeptidase
Microvesicular Steatosis Potentially life threatening Frequently disturbed liver function and coma1 Effects on other tissues If survival, no long-term effects on liver
Reye's Syndrome Mainly young children Presentation:
o acute mild viral illness followed by: vomiting lethargy coma
o fatal in about one-third of patients
Pathogenesis Complex:
o alterations at many points in lipid metabolismo lead to accumulation of neutral fat within
hepatocytes2,3 Manifestation of reversible cell injury4 Nonspecific Variety of causes:
o minor amount: uncertain significance more frequent in elderly5
o more extensive: variety of primary hepatic diseases several systemic conditions
Microvesicular Steatosis Impaired of β-oxidation of lipids Multiple causes include:
o acute fatty liver of pregnancyo Reye's syndrome:
may be: attributable to salicylate use6 sometimes related to inherited
metabolic disorder of mitochondrial β-oxidation:7
many patients have defects in fatty acid oxidation
form of primary mitochondrial hepatopathy8,9
Causes Therapeutic drugs including:
o salicylates: Reye's syndrome
o sodium valproateo intravenous high dose tetracycline10
o in Amazon basin11 Multiple hornet stings12 Inborn errors of mitochondrial fatty acid β-oxidation Inherited urea cycle disorders13
Histopathology Accumulation of triglycerides in cytoplasm of hepatocytes:
o variable degree: may be:
occasional fat droplets
diffuse deposition involving most parenchymal cells
Patterns and Distribution Two patterns:
o macrovesicular steatosis: most common
o microvesicular steatosis Both patterns may be in same biopsy specimen:
o suggests that large droplets form through coalescence of small lipid vacuoles
Macrovesicular Steatosis Large droplet fatty change (Fig. 1)
Fig. 1: Hepatic steatosis in patient with alcohol abuse. The picture shows a mixture of macrovesicular and microvesicular steatosis and a lipogranuloma (upper right corner). (H&E)
Single large vacuole: o distends hepatocyteo displaces nucleus to one side
If uncomplicated used to be regarded as benign and potentially fully reversible:
o this notion has been challenged14,15 Variable zonal distribution and although exceptions:
o most often centrilobular, e.g. in: alcoholic liver disease obesity diabetes
o may become panlobular when more severeo when in periportal zones more common in:
cachexia and protein–energy malnutrition (kwashiorkor)
AIDS after total parenteral nutrition phosphorus poisoning steroid therapy
Severity Mild:
o less than one-third parenchyma involved Moderate:
o one-third to two-thirds parenchyma involved Severe:
o more than two-thirds parenchyma involved
Microvesicular Steatosis Small droplet fatty change (see Figs 1 and 2)
Fig. 2: Acute fatty liver of pregnancy. Detail of lobular parenchyma characterized by microvesicular steatosis and a small number of lymphocytes. (H&E)
Often more difficult to recognize than macrovesicular steatosis Demonstration may require histochemistry
Reye's Syndrome Panlobular steatosis:
o smaller droplets in centrilobular areaso somewhat larger fat vacuoles in periportal regions
May be necrosis of periportal hepatocytes
Lipogranuloma Focal response to rupture of lipid-laden hepatocytes Contains:
o macrophageso occasional lymphocyteso eosinophilso sometimes giant cells (see Fig. 1)
May be: o abundant:
especially in alcohol-induced steatosiso confluento fat-laden macrophages within portal tracts16
Lead to focal fibrosis without great clinical significance
Focal Steatosis Sometimes an isolated finding Usually under liver capsule
Special Stains and Immunohistochemistry In routinely fixed tissue:
o cytoplasmic vacuoles because lipid dissolved during processing
Very small droplet steatosis may be difficult to recognize Histochemical staining helpful:
o lipid demonstrated in: frozen sections using:
oil red O Sudan black
o tissue postfixed in osmium tetroxide17
Diagnosis Not possible to define etiology on pattern of lipid distribution in
individual case: o identification of cause requires close clinicopathologic
correlation Important information in report:
o severityo a mixed pattern of macro- and microvesicular
steatosis: may be of prognostic importance in
alcoholic liver disease18
Other investigationsFocal Steatosis
Identified by modern imaging techniques May be other coincident liver pathology Multifocal steatosis resembling metastatic liver disease
radiologically described in AIDS
Differential Diagnosis- Drug Induced Toxic and Liver Injury- Steatohepatitis- Chronic Hepatitis
Lipogranuloma Serial sections may be required to identify central fat globule and
differentiate from other forms of granuloma19 Fat-laden macrophages within portal tracts:
o must be distinguished from mineral oil granulomas in which:
vacuoles are larger and more irregular generally more fibrosis
STEATOHEPATITISDefinitionSteatosis, necroinflammation and fibrosis of liver. Can be alcoholic or non-alcoholic.
Pathogenesis Fatty liver of alcoholic or nonalcoholic etiology:
o can coincide with or lead to: necroinflammation fibrosis1
Steatosis may be a direct cause of more advanced pathology2 Two-hit hypothesis for development:
o first hit: steatosis
o second hit: presence of other factor(s) such as oxidative
stress3 Lipid peroxidation:
o one mechanism linking steatosis to necroinflammation and fibrosis
o causes oxidative stress of the cell interindividual differences in magnitude
explain individual susceptibility i.e.:3,4 in chronic alcoholics:
alcoholic steatohepatitis (ASH)
people who do not consume alcohol:
nonalcoholic steatohepatitis (NASH)
Oxidizable fat within liver is enough to trigger lipid peroxidation5
NASH Causes include:
o jejunoileal bypass surgeryo gastroplastyo other causes of rapid profound weight loss in obese
subjectso total parenteral nutritiono drugs:
amiodarone perhexiline maleate estrogens and estrogen receptor ligands methotrexate
as at a petrochemical plant in Brazil6o copper toxicityo disorders with extreme insulin resistance
Usually: o etiopathogenesis appears multifactorial:
i.e. obesity, type 2 diabetes, and hypertriglyceridemia7
o can be regarded as hepatic consequence of: metabolic syndrome cardiovascular dysmetabolic syndrome syndrome X8
May be relationship with cryptogenic cirrhosis through shared risk factors of obesity and diabetes9
HistopathologyASHEarly Stages
Predominantly centrilobular zones Usually all lobules Constellation of changes:
o not all present in individual caseo variation without correlation with clinical and
biochemical data in: severity extent of lobular involvement
Steatosis: o commono usually macrovesicular:
worse prognosis if mixed macro- and microvesicular pattern15
even worse prognosis if almost panlobular, predominantly microvesicular steatosis with canalicular bilirubin stasis:
i.e. alcoholic foamy degeneration16
o strong correlation between degree (without steatohepatitis) and number of activated hepatic stellate cells17 stimulated by ethanol metabolites in absence of necroinflammation18
Fibrosis: o constant feature:o different patternso identification requires collagen stains
Most Essential FeaturesLiver Cell Injury
Ballooned hepatocytes: o may contain Mallory bodies:19–22
i.e. perinuclear inclusions (Fig. 1) that are:
Fig. 1: Acute alcoholic hepatitis (ASH). Detail of centrilobular parenchyma, characterized by pericellular fibrosis, steatosis, hydropic swelling of several hepatocytes containing Mallory bodies, and neutrophils swarming around hydropic parenchymal cells (satellitosis). (H&E)
homogeneous eosinophilic variable size and shape complex structures composed
of: aggregated
hyperphosphorylated cytokeratin polypeptides:
including cytokeratins 7, 18, and 19
ubiquitin heat shock proteins tan proteins
easily discernible in routinely stained sections in florid cases
may be small and difficult to identify in mild disease:
immunostaining of cytokeratins or ubiquitin helpful
Alcoholic etiology suspected (but not proved) by: o micronodular patterno dense fibrosis blurring nodular edgeso steatosiso central vein occlusions
Liver biopsy quite useful for diagnosis36
NASH Need for consensus to establish diagnosis regarding:
o minimal histologic criteria: histologic criteria proposed37 include
patterns of injury similar to features of alcoholic injury
not agreed upon by all investigators38–42o maximum amount of alcohol intake43
Subclassification proposed to include etiopathogenesis: o primary NASH:
related to obesity and insulin resistanceo secondary NASH:
post bypass surgery drugs toxins37
Term nonalcoholic fatty liver disease (NAFLD) proposed to incorporate spectrum of steatotic syndromes not induced by alcohol41
Not all lesions of alcoholic liver disease in NASH Not all lesions of NASH in alcoholic liver disease33 A system for grading and staging histologic lesions in NASH
published
Differential Diagnosis- Drug Induced Toxic and Liver Injury- Chronic Hepatitis- Steatosis
ASHViral Hepatitis
May be suspected clinically, but liver histopathology different
Chronic Venous Congestion May be confusion if incomplete picture of ASH, with only
perivenular and pericellular centrilobular fibrosis
Diseases Unrelated To Alcohol Mallory bodies, neutrophils, and fibrosis are part of
histopathology of diseases unrelated to alcohol such as: o chronic cholestasis:
easy to differentiate due to periportal predominance of changes
o Wilson's disease: always consider, especially in younger
patients
Hypervitaminosis A May cause pericellular fibrosis progressing to cirrhosis45
Hepatocellular Siderosis In some alcoholics May be confused with genetic hemochromatosis:
o may be solved by: quantitative tissue iron determination calculation of hepatic iron index46
NASH Identical histopathology
ManagementASH
On stopping alcohol: o parenchymal regeneration improveso nodules increase in sizeo all features of alcoholic etiology disappear
Parenchymal changes appear with time superimposed on early bilirubin stasis
Bilirubin stasis: o gradually extends toward periportal parenchyma
Lymphocytic inflammatory infiltrate: o restricted to area with bilirubin stasiso mildo in most forms lasting for weekso apparently secondary to cholestatic changes
Chronic Incomplete Cholestasis Bilirubin stasis not a feature:
o except if: terminal decompensating phase superimposed pathologic changes:
e.g. drug-induced liver damage
Histopathologic Diagnosis of Chronic Cholestasis Applies to both complete and incomplete chronic cholestasis Parenchymal, portal, and periportal alterations as outlined below
Parenchymal Changes Include:
o cholate stasiso cholestatic liver cell rosetteso feathery degenerationo xanthomatous cellso bile infarcts
Cholate Stasis Periportal hepatocyte lesion:
o thought to be due to membrane-damaging effect of retained bile acids4
Hepatocytes: o swollen (Fig. 2)
Fig. 2: Cholate stasis in periphery of parenchymal nodule in cirrhotic liver of patient with end stage primary sclerosing cholangitis. The hepatocytes near the fibrous septum (lower part) show hydropic swelling, clumping of the cytoplasm, and Mallory bodies. (H&E)
o paleo coarsely granular:
contain granules of lysosomal copper, complexed with copper-binding protein (metallothionein):
stainable with: rhodanine (copper)
(Fig. 3)
Fig. 3: Cholate stasis in periphery of cirrhotic nodule in patient with stage 4 primary biliary cirrhosis. Lysosomal copper–metallothionein complexes appear as red-stained granules in the copper-specific rhodanine stain.
orcein (metallothionein) (Fig. 4
Fig. 4: Cholate stasis in periportal parenchyma in patient with primary sclerosing cholangitis. The picture shows orcein-positive granules in periportal hepatocytes, representing lysosomal localization of copper binding protein (metallothionein). (Orcein stain)
)o with time:
contain Mallory bodieso very late stages:
may be bilirubin inclusions
Cholestatic Liver Cell Rosettes Useful diagnostic feature5 Tubular rearrangement of liver cell plates that are normally one
o lined by four or more hepatocytes: may show feathery degeneration
o central lumen: may:
vary greatly in diameter (Fig. 5)
Fig. 5: Cholestatic liver cell rosettes. Liver biopsy of patient with primary sclerosing cholangitis. The involved hepatocytes appear in tubular arrangement. (H&E)
appear empty be filled with eosinophilic or
bilirubin-stained material in variable degrees of inspissation
Feathery Degeneration Hydropic swelling of:
o single cellso groups of parenchymal cells
May be some bilirubin impregnation of remaining visible cytoplasm in chronic complete cholestasis
Xanthomatous Cells Feature of longstanding incomplete and complete cholestasis Lipid-laden histiocytes with foamy cytoplasm:
o accumulate in: parenchyma portal tracts
o single or in clusterso represent tissular expression of hyperlipidemia that
accompanies chronic cholestasis
Bile Infarcts So-called Charcot–Gombault infarcts Late parenchymal lesion in severe cholestasis of long duration Mainly in large duct obstruction Lesions consist of necrotic hepatocytes:
o mostly paraportalo possibly bilirubin impregnation of central necrotic areao gradually replaced by organizing mesenchymal tissueo finally result in fibrous scars
Two Further Characteristic Changes In Neonatal Cholestatic Liver Diseases
Parenchymal Multinucleated Giant Cells Due to syncytial fusion of several mononucleated hepatocytes Variable:
o number of nucleio location
Often contain pigment granules corresponding to: o bilirubino lipofuscino hemosiderin
May: o appear necrotico surrounded by neutrophil polymorphs6
o erythrocyte precursor cellso myeloid precursor cellso megakaryocytes
Common
Periportal And Architectural Changes Comprise:
o ductular reactiono ductular reabsorptiono periductular fibrosiso biliary fibrosiso final stage of biliary cirrhosis
Ductular Reaction Increased number of ductular profiles in periphery of portal tract:
o gradually extend into periportal parenchyma toward neighboring portal tracts in periphery of liver lobule
o accompanied by: edema neutrophil infiltration (Fig. 6)
Fig. 6: Ductular reaction in chronic cholestasis. Liver biopsy from patient with primary sclerosing cholangitis. The picture shows a mildly inflamed portal tract (upper part) with (at 8 o'clock) a focus of ‘ductular reaction’ composed of bile ductules, edematous stroma, and some neutrophil infiltration. (H&E)
If obstruction of extrahepatic bile ducts: o mainly due to increased bile pressure8,9o involves elongation of pre-existing bile ductules9o has been described as ‘marginal bile duct
proliferation’10 In other cholestatic diseases, not necessarily obstructive:
o proinflammatory cytokines may be predominant triggers11,12
o cholangiocytes lining ductules may show signs of reabsorption:
reflected in vacuolization of cytoplasm accumulation of bilirubin and lipofuscin
Biliary Fibrosis Progressive ductular reaction with periductular fibrosis eventually
results in fibrous linkage of adjacent portal tracts: o i.e. portal–portal septal fibrosiso potentially reversible14 because basic
angioarchitectural pattern of liver preserved15
Biliary Cirrhosis Final stage in disturbance of lobular architecture Characterized – like any cirrhosis – by:
o additional portal–central fibrous septao nodular parenchymal regeneration
Ongoing cholestasis: o characterized by:
persistence of ductular reaction edema periductular inflammation fibrosis
o together with lesions of cholate stasis in nodular periphery creates at low magnification impression of clear halo between cirrhotic nodules and fibrous septa:
indicates actively progressing disease in its cirrhotic stage
Special Stains and ImmunohistochemistryCholate Stasis
Earliest stages: o may be revealed by immunostaining for cytokeratin 7:
reveals a phenotypic switch to a biliary type of intermediate filament cytoskeleton in periportal hepatocytes (Fig. 7)
Fig. 7: Primary biliary cirrhosis. Detail of portal tract and surrounding parenchyma. This cytokeratin 7 immunostain highlights an increase in the number of ductular structures at the portal tract periphery; expression of cytokeratin 7 in periportal hepatocytes (early stage of cholate stasis), and a few scattered, small cytokeratin 7 positive cells at some distance from the portal tract (presumed hepatic progenitor cells). (Immunostain for cytokeratin 7)
With time: o cytokeratin 7 expression extends with decreasing
gradient from limiting plate toward center of the lobule over a distance of several cells16
Cholestatic Liver Cell Rosettes Some or all lining hepatocytes may
o express bile duct-type cytokeratin i.e.: cytokeratin 7 tissue polypeptide antigen (TPA):
indicates partial shift toward bile duct cell phenotype (Fig. 8)
Fig. 8: Cholestatic liver cell rosettes. Immunostaining for cytokeratin 7 reveals cholestatic liver cell rosettes to better advantage. Normal hepatocytes do not express cytokeratin 7, whereas cells in cholestatic rosettes express this intermediate filament to variable extent.
should not be misinterpreted as expression of hepatocellular regeneration
Diagnosis If incomplete and anicteric:
o no microscopically visible accumulation of bilirubin in liver tissue sections
o underscores usefulness of distinguishing between: bilirubin stasis cholate stasis
Differential Diagnosis- Paucity of Interlobular Bile Ducts- Neonatal Giant Cell Hepatitis- Primary Sclerosing Cholangitis- Primary Biliary Cirrhosis- Drug Induced and Toxic Liver Injury
Bilirubin Stasis Dark brown to black deposits (in hepatocytes, canaliculi, Kupffer
cells, and ductules) in erythropoietic protoporphyria: o easily identified by polarized light:
protoporphyrin deposits have a red to yellow birefringence with a Maltese cross configuration in coarser (ductular) deposits (Figs 9 and 10)
Fig. 9: Erythropoietic protoporphyria. Dark brownish-black deposits of protoporphyrin in hepatocytes, canaliculi, Kupffer cells, and ductules. (H&E)
Fig. 10: Erythropoietic protoporphyria. The deposits are birefringent, and show a Maltese cross picture of red birefringence in the larger deposits. (Polarized light)
Extramedullary Hematopoiesis Not a reliable criterion for differentiation between various
cholestatic diseases such as biliary atresia and neonatal hepatitis
Biliary Fibrosis Distinguish from true biliary cirrhosis
Staging/gradingStaging In Chronic Cholestatic Liver Diseases
Based on periportal and architectural changes Stage 1:
o portal Stage 2:
o periportal Stage 3:
o septal Stage 4:
o Cirrhotic
Vanishing Bie Duct DiseasesExtrahepatic Bile Duct AtresiaDefinitionCongenital disorder where there is progressive necroinflammatory destruction of intrahepatic and extrahepatic bile ducts.
Clinical Features May start:
o in uteroo in perinatal period
Pathogenesis Etiology unknown Probably heterogeneous and represents common phenotype of
several underlying disorders1,2
Histopathology Involves both extrahepatic and intrahepatic ducts:
o originally maximal involvement of part or all extrahepatic duct system
Panbiliary Progressive necroinflammatory destruction of bile ducts During first 3–4 weeks:
o mostly nonspecific bilirubin stasiso some parenchymal giant cellso foci of extramedullary hematopoiesis
Gradual development: o portal edemao ductular reaction:
considered most reliable, though not pathognomonic criterion in diagnosing extrahepatic obstruction in liver specimens3
Ductules often contain inspissated bile concrements Later stages:
o periportal fibrosiso finally resulting in secondary biliary cirrhosis
Intrahepatic ducts: o irregularity of lining cholangiocytes, which feature:
vacuolization nuclear pyknosis atrophy infiltration by inflammatory cells (Fig. 1)
Fig. 1: Extrahepatic bile duct atresia (EHBDA). Detail of a portal tract in liver biopsy from neonate with EHBDA, showing mild inflammatory infiltrate, and a bile duct with irregular outline and epithelial damage: vacuolization in some cholangiocytes, apoptosis in others, and some inflammatory cells inside the basement membrane. (H&E)
Thickening of basement membrane Progressive atrophy and disappearance of ducts4 Histopathology of obliterated extrahepatic ducts:
o various stages of: nonspecific inflammation epithelial desquamation and necrosis ulceration fibrosis5,6
Early Severe Variant In >25%7–9 of cases interlobular bile ducts appear in early
embryologic shape: o so-called ‘ductal plate malformation’ (Fig. 2)
Fig. 2: Extrahepatic bile duct atresia (EHBDA), early severe type in stage of advanced fibrosis. The picture shows part of a large, fibrous portal area, with recognizable hepatic artery branches, barely visible or no portal vein branches, and bile duct structures in ductal plate configuration (ductal plate malformation).
The lining cholangiocytes show involutional changes: flattening, shrinkage, and nuclear pyknosis. (H&E)
o suggests antenatal start associated with arrest of remodeling of embryonic ductal plates10
Histology reveals advanced fibrosis, even at 4 weeks of age
Diagnosis Liver biopsy cornerstone in diagnosis
Differential Diagnosis- Drug Induced and Toxic Liver Injury- Neonatal Giant Cell Hepatitis- Inborn Errors of Metabolism
Other causes of obstruction: o mainly choledochal cyst in this neonatal period:o degenerative lesions of intrahepatic ducts
Neonatal giant cell hepatitis: o no or much less ductular reactiono more intralobular than perilobular fibrosis
Chronic liver injury by parenteral nutrition Several inborn errors of metabolism
Management Hepatic portoenterostomy or Kasai operation with resection of
obliterated extrahepatic ducts Correlation between number and size of patent ducts in porta
hepatis at portoenterostomy and success of procedure controversial:11,12
o some assess bile duct luminal size in frozen sections of proximal resection margin during a Kasai procedure
o some consider total diameter of all prehilar structures important, with total diameter >400μm indicating favorable prognosis for adequate bile drainage
Paucity of Interlobular Bile Ducts
DefinitionCongenital disorder where there is destruction and loss of small interlobular bile ducts. Divided into syndromic (Alagille's) and non-syndromic forms associated with alpha-1-antitrypsin deficiency, rubella, Turner's syndrome, trisomy 21 and others.
Clinical Features Subdivided according to associated clinical features into
syndromic and nonsyndromic PILBD Syndromic PILBD:
o Alagille's syndrome or arteriohepatic dysplasiao abnormal facieso vertebral, cardiac, ocular, and renal abnormalities:
o most frequent diagnosis for conjugated hyperbilirubinemia in first month of life3
o destruction of interlobular ducts starts early (before 3 months) and progression usually faster than in syndromic PILBD2,3
Histopathology Nonspecific, inflammatory destruction of interlobular ducts,
resulting in progressive ductopenia Changes:
o mainly of chronic incomplete cholestasis and neonatal cholestasis
Special Stains and Immunohistochemistry Immunostains for cytokeratin 7 (or 19) or tissue polypeptide
antigen (TPA): o for better visualization of interlobular ducts:4
especially in very young children5
Diagnosis Requires sufficiently large biopsy specimen and quantitative
evaluation of interlobular ducts: o needle biopsy may suffice if contains at least five portal
tracts3o 70–80% of branches of hepatic artery normally
accompanied by duct of approximately similar size near center of portal tract
‘widowed artery’ signals missing duct6 Ratio of number of interlobular ducts to number of portal tracts:
o 0.9–1.8 in normal children and adults7o in PILBD:
originally defined as <0.5 now also defined as a reduced bile duct to
portal tract ratio >0.5: especially when ducts with
degenerative changes8 in premature infants <0.9 may be normal:9
due to incomplete bile duct development at birth
Differential Diagnosis- Extrahepatic Bile Duct Atresia- Drug Inuced Toxic and Liver Injury- Neonatal Giant Cell Hepatitis- Alpha 1 Antitrypsin Deficiency
Primary Biliary CirrhosisDefinition
Autoimmune disorder in middle-age females where there is chronic non-suppurative destruction of bile ducts resulting in cirrhosis. Antimitochondrial antibody to M2 component of pyruvate dehydrogenase is found in 90% of the cases.
Clinical Features Nearly 10× more frequent in females than males Usually insidious onset starting with pruritus
Pathogenesis Considered to be autoimmune:
o often other autoimmune disorderso proof strong, but only indirect and circumstantial1
Gross Pathology Basic lesion:
o chronic, nonsuppurative, destructive cholangitis: possibly ending in cirrhosis2
HistopathologyEarly Stage
Involves ducts 40–80μm diameter: o i.e. segmental and larger interlobular ductso size may be difficult to estimate because some enlarge
apparently through: damage to basement membrane reactive hyperplasia of lining epithelium3
Lesions: o focal in livero segmental within duct system
Affected duct segments: o epithelial swelling or eosinophil condensationo possibly stratificationo infiltration by lymphocytes and plasma cellso damage of basement membrane may lead to rupture
inflammatory cells accumulate beside or around duct (Fig. 1):
Fig. 1: Granulomatous cholangitis in primary biliary cirrhosis (PBC). Detail from a portal tract with dense lymphoplasmacytic infiltrate and lymphoid aggregate (left). The interlobular bile duct (center) shows a focal rupture of its cholangiocytic lining, at the site of an adjacent epithelioid granuloma. (H&E)
mainly lymphocytes: sometimes aggregated in
lymphoid follicle with germinal center
may be: abundant plasma cells quite prominent eosinophils neutrophils single or small clusters of
necrosis):7,8intralobular ‘invading’ lymphocytes play role in development of septal fibrosis9 (Fig. 2)
Fig. 2: Primary biliary cirrhosis, stage 3. The picture shows portal–portal septal fibrosis (septal stage 3), portal inflammation with lymphoid aggregate, absence of interlobular bile duct (ductopenia), and cholate stasis in periportal and periseptal parenchyma. (H&E)
may be variable degree of intralobular necroinflammation10
May be liver cell dysplasia of large and small cell type11 Progressive ductopenia
Advanced Cases Portal lymphoid aggregates mark site of disappeared bile ducts
(see Fig. 2) Cholestatic and hepatitic features result in progressive fibrosis
with: o portal–portal septum formationo additional portal–central septa9
Resulting cirrhosis:
o biliary type when cholestatic features predominateo more macronodular type when predominance of
hepatitic featureso may be any combination of two patterns
Hepatitic-type lesions appear most important for progression of fibrosis12
Special Stains and Immunohistochemistry Antimitochondrial antibodies:
o in >90% of patients1o most specific against M2 component of pyruvate
dehydrogenase complex Aberrant expression of cytokeratin 7 in hepatocytes (Fig. 3) may
be marker for:
Fig. 3: Primary biliary cirrhosis. Detail of portal tract and surrounding parenchyma. This cytokeratin 7 immunostain highlights an increase in the number of ductular structures at the portal tract periphery; expression of cytokeratin 7 in periportal hepatocytes (early stage of cholate stasis), and a few scattered, small cytokeratin 7 positive cells at some distance from the portal tract (presumed hepatic progenitor cells). (Immunostain for cytokeratin 7)
o degree of cholestasiso progression13
Diagnosis Liver biopsy:
o important in diagnosis and staging14o characteristic bile duct lesions not always seen:
due to sampling variability prevents firm histologic diagnosis
A florid bile duct lesion in PBC can be categorized as: o lymphocytico pleomorphico granulomatous cholangitis (see Fig. 1):
most diagnostic feature
Differential Diagnosis- Nodular Regeneration- Chronic Hepatitis- Drug Induced and Toxic Liver Injury- Primary Scelrosing Cholangitis
Chronic hepatitis, especially viral hepatitis C: o in viral hepatitis C, affected duct segment shows:
vacuolization and stratification of cholangiocytes
preservation of basement membrane16 no cholestatic features
Drug-induced bile duct damage: o usually ducts of smaller caliber than in PBCo clinical history comprises episode of jaundice17
Conditions characterized by bile duct damage and granulomas:
may be difficult because may lead to: ductopenia chronic cholestatic liver disease
final diagnosis requires consideration of clinical context and laboratory data
Immune cholangitis18 or autoimmune cholangiopathy:19o clinically, biochemically, and histologically similar to
PBC, but antimitochondrial antibodies negativeo represents antimitochondrial antibody-negative
PBC:20 but reactivity to recombinant mitochondrial
antigens by immunoblotting in about 75% of such patients21
Autoimmune hepatitis–PBC overlap syndrome:22o rareo clinical, biological, and histologic features of PBC and
autoimmune hepatitis, simultaneously or sequentiallyo higher degrees of ‘hepatitic component’ of PBC, which
responds to corticosteroid therapy23
Staging/grading Several systems proposed for staging2,24–26 Most popular applicable to any vanishing bile duct disease:24
o distinguishes four stages: stage 1:
portal stage 2:
periportal stage 3:
septal fibrosis stage 4:
cirrhosis Staging in small needle biopsy specimens valuable if interpreted
with caution: o considerable variability in degree of fibrosis in different
parts of liver
Primary Scelrosing CholangitisDefinitionDisorder of the biliary tract in which there is inflammation and sclerosis of usually the medium and large ducts. About 6% of cases have small duct involvement only. Associated with inflammatory bowel disease.
Clinical Features One of most common adult chronic cholestatic liver diseases 75% cases are male Average age at diagnosis 40 years:
o sometimes children1 Typically associated with inflammatory bowel disease (70%)2–4
Gross Pathology Inflammation, strictures, and saccular dilatations in biliary system Any part of biliary tree
Histopathology Changes depend on:
o stage of diseaseo site of biopsy:
Portal Tracts Proximal to strictures:
o only features of obstruction and cholangitis Affected by primary disease:
o pleomorphic and fibrous–obliterative cholangitis5
Key lesion: o onion skin-type periductal fibrosis (Fig. 1):
Fig. 1: Primary sclerosing cholangitis. Detail of portal tract with moderately dense inflammatory infiltrate (mainly lymphocytes, some eosinophils) and concentric, lamellated, periductal fibrosis (‘onion skin’ fibrosis) around the interlobular bile duct (center). (H&E)
with degeneration and atrophy of epithelial lining:
results in disappearance of duct and eventual replacement by a fibrous scar
loss of ducts more frequent in smaller portal tracts
sometimes scars unusually prominent and resemble keloid scars6,7
in <40% of biopsy specimens5 more often medium-sized
tracts8 not pathognomonic – also in
other types of biliary disease not present in every stage of
disease If longlasting and more severe disease:
o portal fibrosis more markedo fibrous septao biliary cirrhosis
More progressive disease: o moderate to severe lymphocytic type of interface
hepatitis9 Less severe disease:
o only mild and insignificant lesions over several years10 Increased risk of developing cholangiocarcinoma:11
o strong association with dysplasia of bile duct epithelium12
Parenchymal Changes Less striking than portal changes Correspond to features of chronic cholestasis May be nodular regenerative hyperplasia before precirrhotic
stage
Special Stains and Immunohistochemistry PAS–diastase staining:
o thickening of basement membrane around damaged ducts (Fig. 2), or
Fig. 2: Primary sclerosing cholangitis. Overview of portal tract and periportal parenchyma. This portal tract shows only mild inflammation; two interlobular bile ducts show clear-cut thickening of their basement membrane, a helpful diagnostic feature. (PAS–diastase stain)
o wrinkled empty basement membranes13
Diagnosis Usually combined large and small duct PSC Small duct PSC corresponds to involvement of only
microscopically identifiable (septal and interlobular) ducts: o previously indicated by now obsolete term
pericholangitis14
Other investigations Cholangiography
Differential Diagnosis- Drug Induced and Toxic Liver Injury- Large Duct Obstruction- Primary Biliary Cirrhosis
PBC: o may be difficult to differentiate in later stageso epithelioid granulomas:
also in about 4% of PSC cases, but not as part of granulomatous cholangitis15
o florid portal inflammation with or without lymph follicle formation favors PBC
Overlap autoimmune hepatitis and PSC described16–18 Other vanishing bile duct diseases
CHILDHOOD DISORDERS AND DISORDERS OF METABOLISMALPHA-1 ANTITRYPSIN DEFICIENCYDefinitionGenetic endoplasmic storage disease where there is mutation in the serum glycoprotein and protease inhibitor AIAT. The mutated protein (homozygous SERPINA1 Z being the most common) becomes deposited in the ER of hepatocytes, resulting in its deficiency in the serum and associated pulmonary emphysema.
Clinical FeaturesNeonatal Cholestasis
Most common liver disease in children: o seen in 11% of infants
Usually resolves without therapy by 6 months of age In ≤10%:
o prurituso cirrhosis
Poor prognosis if persistent hyperbilirubinemia beyond 1 year of age1,2
Alpha-1 Antitrypsin Deficiency In Adults3 Usually presents with pulmonary emphysema4 Liver disease:
o incidence increases with age5 Increased prevalence of hepatitis B and C viral infection:
o may contribute to hepatic complications6–8 Increased risk for:
o hepatocellular carcinoma in adult homozygous PiZ with or without cirrhosis9,10
o chronic liver disease in middle-aged or old adults with heterozygous PiZ11
Pathogenesis An endoplasmic reticulum storage disease:
o molecular abnormality of alpha-1-antitrypsin: hinders transfer through endoplasmic
reticulum: results in:
retention in endoplasmic reticulum
deficiency in plasma12
Alpha-1-antitrypsin: o serum glycoproteino protease inhibitor (Pi)o >70 allelic variants13o usual phenotype PiMo most common deficiency alleles:
PiZ: amino acid lysine substitution for
glutamic acid at position 34214 PiS
Histopathology Globular inclusions:
o in endoplasmic reticulum of periportal hepatocytes15o eosinophilico PAS–diastase positiveo 1–10μm diameter (Fig. 1)
Fig. 1: Alpha-1-antitrypsin deficiency. Detail of periportal parenchyma, showing PAS-positive inclusions of varying size in the majority of periportal hepatocytes. (PAS–diastase stain)
Neonatal Cholestasis Parenchymal giant cells Ductular reaction Fibrosis Paucity of interlobular bile ducts:16
o in up to 10% of cases
Alpha-1 Antitrypsin Deficiency In Adults3 Liver disease:
o varying degrees of fibrosiso cirrhosis
Special Stains and Immunohistochemistry Immunostaining with polyclonal anti-alpha-1-antitrypsin Specific monoclonal antibody:
o allows identification of PiZ gene products17 Large areas of lobular hepatic parenchyma may be
immunopositive for alpha-1-antitrypsin in PiMZ individuals
Differential Diagnosis- Neonatal Giant Cell Hepatitis- Paucity of Interlobular Bile Ducts
Immunoreactive globules in several liver diseases:19o alpha-1-antitrypsin phenotyping in plasma by
immunodiffusion or electrophoresis needed for final diagnosis
Neonatal Cholestasis May resemble extrahepatic bile duct atresia:
o need to screen for alpha-1 antitrypsin deficiency before a Kasai procedure
Genetics Alpha-1-antitrypsin:
o >70 allelic variants13o usual phenotype PiMo most common deficiency alleles:
PiZ: amino acid lysine substitution for
glutamic acid at position 34214 PiS
DISORDERS OF COPPER AND IRON METABOLISMWILSON’S DISEASEDefinitionRare autosomal recessive disorder where there is tissue injury from increased copper deposition in the liver, brain, cornea and kidneys. The mutation is localized to chromosome 13q14-21.
Clinical Features Rare Autosomal recessive:
o gene mutation on chromosome 13q14–211 After 5 years of age may present with:2
o acute hepatitiso fulminant hepatitiso chronic hepatitiso cirrhosis
Pathogenesis Tissue injury due to copper overload in:
o liver
o other organs: brain cornea kidneys
Histopathology Histologic abnormalities precede clinical appearance Early stage:
o steatosiso sometimes lipogranulomas3
Periportal hepatocytes: o may be:
strikingly abundant lipofuscin glycogen vacuoles in nuclei4
Kupffer cells: o may be laden with iron:
due to frequent acute hemolytic crises Progressive fibrosis with fine septa extending from portal tracts Sometimes portal tracts infiltrated with mononuclear
inflammatory cells: o indistinguishable from chronic hepatitis due to other
causes4–6 Untreated, progresses to cirrhosis Helpful diagnostic clues:
o steatosiso ballooned hepatocyteso glycogenated nucleio moderate to marked copper depositiono Mallory bodies in periportal hepatocyteso lymphocytic portal and interface inflammationo possibly occlusive venous lesions4
If fulminant hepatic failure: o extensive parenchymal necrosiso collapse of the reticulin frameworko nodular parenchymal regenerationo development of a cirrhotic pattern7
Electron microscopy: o characteristic mitochondrial and lysosomal changes8
Special Stains and Immunohistochemistry Cytochemical staining for copper and copper-binding protein:
o may be useful in establishing diagnosis (Fig. 1)
Fig. 1: Wilson's disease, cirrhotic stage. This rhodanine stain reveals accumulation of copper (red granules) in varying degree, most pronounced in a nodular cluster of hepatocytes (left). (Rhodanine stain)
Timm's silver stain: o appears most sensitive technique10
Stains may be negative in some stages of the disease
Diagnosis Quantitative determination of hepatic copper:
o may be necessary for final diagnosiso can be performed on routinely processed paraffin-
embedded tissue11 Great variety of possible lesions:
o creates problems for histopathologisto consider in differential diagnosis of hepatocellular
disease at all ages, but especially if young Young and asymptomatic:
o hepatic copper levels high, but difficult to demonstrate histochemically due to diffuse distribution in hepatocyte cytoplasm
Older and signs of disease: o copper metal diffusely distributed and intralysosomal
Advanced disease: o all copper confined to lysosomes:12
more easily recognized granular pattern Cirrhotic stage:
o parenchymal nodules may vary strikingly in copper content (see Fig. 1)
Other investigations Liver biopsy:
o useful for: diagnosis monitoring
Differential Diagnosis- Steatohepatitis- Cirrhosis- Drug Induced and Toxic Liver Injury- Cholestasis- Chronic Hepatitis
Copper and metallothionein may accumulate in other diseases e.g.:
o cholestasiso Indian childhood cirrhosis
Neonatal liver usually contains high levels of copper13
Genetics Autosomal recessive:
o gene mutation on chromosome 13q14–211
Management Penicillamine or zinc acetate:
o may arrest diseaseo prevent development in siblings
IRON OVERLOADDefinitionDeposition of iron in the liver secondary to chronic anemia, blood transfusion, chronic renal failure and porphyria cutanea tarda.
Clinical Features Demonstrable iron in tissues Causes:
o genetic hemochromatosiso chronic anemia including thalassemia:
often termed secondary hemochromatosiso neonatal iron overload:
rareo blood transfusiono hemolysiso chronic renal failureo porphyria cutanea tardao ingestion of excessive amounts of iron e.g. due to:1
self-medication with iron compounds use of iron containers by South African
blacks for brewing traditional beers
Pathogenesis Neonatal iron overload:
o etiology unknowno no relationship with genetic hemochromatosiso putative environmental agents suspected to interact
with one or more factors intrinsic to developing fetal liver2
HistopathologyIron Distribution
Varies according to cause Exogenous siderosis loads Kupffer cells first (Fig. 1)
Fig. 1: Secondary siderosis. Hemosiderin (blue) is located exclusively in Kupffer cells, sparing the hepatocytes. (Perls' iron stain)
Always most pronounced in periportal hepatocytes Predominantly parenchymal in:
HEMOCHROMATOSISDefinitionAutosomal recessive disorder of iron metabolism most common in Northern Europeans where there is increased iron deposition in liver, heart, pancreas and gonads. The most common mutation is missense (C282Y) of the HFE gene on chromosome 6p.
Clinical Features Autosomal recessive:
o heterozygosity rarely associated with liver damage due to iron alone1
Most common inherited disorder in white Caucasians2 Risk of hepatocellular carcinoma:
o incidence ≈15%: predominantly in males
o not prevented by removal of iron3
Pathogenesis In Northern Europe:
o >90% of cases homozygous for missense mutation (C282Y) in HFE gene on short arm of chromosome 6:
o mutation leads to dysregulation of intracellular iron homeostasis in enterocytes:
results in inappropriately high iron absorption
o role of a second mutation (H63D) in HFE gene unclear:4
C282Y mutation alone leads to mild hepatic siderosis, with exception of H63D/C282Y compound heterozygotes5
Histopathology Progressive iron accumulation in:
o livero hearto pancreaso other organs
Rate of accumulation varies: o even within same family
If Young Stainable iron in periportal hepatocytes:
o positivity in males generally greater than in females of same age
o first abnormality
With Advancing Age Progressive deposition of hemosiderin toward centrilobular area:
o usually maintains decreasing portal–central gradient Some Kupffer cells and occasional portal macrophage may
become iron positive: o overwhelmed by almost exclusive parenchymal storage
Hepatocellular iron appears as pericanalicular granules representing lysosomal storage (Fig. 1)
Fig. 1: Parenchymal siderosis in genetic hemochromatosis. Detail of lobular parenchyma showing marked parenchymal siderosis in typical lysosomal (pericanalicular) localization. There was a decreasing portal–central gradient in lobular siderosis (not shown). (Perls' iron stain)
With Progressing Siderosis Fibrosis with:
o expansion of portal tracts: carry iron-laden macrophages
o small fibrous spurs conferring spiked contour to portal tracts
o some increase in ductular profiles: usually without marked inflammation
Further advancement: o results in diffuse micronodular pattern with portal-
based septal fibrosis: resembles secondary biliary cirrhosis
Excessive alcohol consumption: o induces shift of hemosiderin from parenchymal to:
Kupffer cells macrophages in fibrous septa7
In later stages of heavy iron overload: o occasional small areas:
without or with little parenchymal siderosis and only some Kupffer cell iron load
most often seen in established cirrhosis represent preneoplastic lesion8
After Therapeutic Phlebotomies Steady disappearance of stainable iron:
o pattern reverse of accumulation: periportal hepatocytes remain Perls'
positive longer: iron removal unmasks brown
lipofuscin-resembling pigment in hepatocytes and portal mesenchyme
o portal collagen most resistant to iron removal
Special Stains and ImmunohistochemistryPerls' Stain Using Acid Ferrocyanide
Best demonstrates siderosis Gives Prussian blue reaction with ferric compounds:
o ferritino hemosiderin
Ferritin dispersed in hyaloplasm: o gives diffuse bluish tint to the cell's cytoplasm
Intense blue granules: o correspond to ferritin and hemosiderin packed
together within siderosomes (iron-laden lysosomes)9 Evaluation requires attention to:
o extent (grade or amount) of stainable iron: semiquantitative assessment of stored
tissue iron achieved in different ways: simplest system grades from 1
(minimal) to 4 (massive deposits) grades 2 and 3 indicate
intermediate amountso distribution in different cell types of portal tract and
lobule
Diagnosis Important:
o cirrhosis can be prevented by appropriate treatment of patient and homozygous relatives, with return of life expectancy to normal3
Usually based on clinical, biochemical, genetic, and histopathologic data
Genetic diagnosis a reality:16o but phenotypic diagnosis remains important17
Unexplained small amounts of iron in hepatocytes should always raise suspicion of early stage:
o calculation of (H)HII and further serum biochemistry may help establish diagnosis
Other investigations Chemical determination of tissue iron:
o performed on: liver tissue separated from specimen taken
for histology block deparaffinized after histopathologic
study: ensures tissular composition of
sample known10 Hepatic iron index (HII):11
o chemically measured hepatic iron concentration (μmol/g dry weight)/patient's age in years
o enables distinction of genetic hemochromatosis (HII ≥1.9) from heterozygous individuals and patients with siderosis from other causes
Chemically measured HII correlates well with histological hepatic iron index (HHII) (dividing by the age in years)12
Also grading system for estimation of iron in hepatocytes, mesenchymal cells, cholangiocytes, blood vessels, and connective tissue, generating a score between 0 and 60:13
o together with HHII14 helpful in assessment of genetic hemochromatosis
Microscopic evaluation: o may allow blocked tissue to be preservedo can be used to quantitate when chemical iron
determination is not possible Computerized image analysis:
o correlates well with classical assayso additional technique
Differential Diagnosis- Iron Overload- Cirrhosis
Genetics In Northern Europe:
o >90% of cases homozygous for missense mutation (C282Y) in HFE gene on short arm of chromosome 6:
o mutation leads to dysregulation of intracellular iron homeostasis in enterocytes:
results in inappropriately high iron absorption
o role of second mutation (H63D) in HFE gene unclear4 C282Y mutation alone leads to mild hepatic
siderosis, with exception of H63D/C282Y compound heterozygotes5
DefinitionNon-cirrhotic non-neoplastic nodular transformation of the liver parenchyma. It consists of nodular regenerative hyperplasia thought to be caused by portal venous thrombosis, the closely related partial nodular transformation which is limited to the perihilar region near the porta hepatis, and focal nodular hyperplasia due to arterial hyperplasia with nodular parenchymal hyperplasia and cholestasis.
Clinical Features Accompanies limited number of disorders, such as:
o congestive heart failureo Felty's syndromeo lymphoproliferative disorderso drug-induced reactions, usually associated with portal
hypertension May be:
o part of early noncirrhotic stages of primary biliary cirrhosis1
o in liver containing metastatic or primary liver tumor2 Sometimes:
o portal hypertensiono elevated:
alkaline phosphatase γ-glutamyl transpeptidase
Pathogenesis Basic lesion postulated to be portal venous thrombosis, resulting
in: o parenchymal atrophyo compensatory hyperplasia3
Arterial lesions, particularly age-associated arteriosclerosis, may contribute3
Gross Pathology Non-neoplastic nodules not delimited by fibrous septa3
Histopathology Nodules of hyperplastic hepatocytes:
o in plates > one cell thicko adjacent parenchymal cells (usually centrilobular
areas): compressed:
sometimes with perisinusoidal fibrosis
atrophico portal tracts:
generally in centero interface with other nodules:
not defined by fibrous septa: differentiates lesion from
cirrhosis (Table 1)
Table 1. Differential diagnosis of nodular regenerative hyperplasia
Disease Diffuse involvement of the liver
Septa
Nodules
Cirrhosis + + +Nodular regenerative hyperplasia
+ – +
Focal nodular hyperplasia
– + +
Generally: o no or minimal inflammationo no liver cell damage
Vascular changes: o may be subtle and inconspicuous in needle biopsies
May be aberrant ‘paraportal shunt’ vessels of noncirrhotic portal hypertension (portal phlebosclerosis):4
o in portal hypertensiono without portal hyperpressure (or possibly subclinical
stage) Nodularity better revealed on reticulin stain5
Diagnosis Histopathologic diagnosis:
o easier on surgical specimenso possible on needle biopsies
LIVER DISEASE IN PREGNANCYACUTE FATTY LIVER OF PREGNANCYDefinitionRare but serious metabolic disorder affecting primigravidae and multipara women in the last weeks of gestation characterized by fatty replacement of liver. Believed to be caused by a fatty acid transport and mitochondrial oxidation disorder of the fetus.
Clinical Features Rare Most serious pregnancy-associated disease Develops in last weeks of gestation Both primigravidae and multipara Unexplained jaundice in late pregnancy Usually does not recur in subsequent pregnancies1
Pathogenesis Fatty acid transport and mitochondrial oxidation (FATMO)
disorder of fetus2
Gross Pathology Yellow Frequently small due to substantial loss of parenchyma
Histopathology Microvesicular steatosis:
o most characteristic featureo usually involves entire liver lobuleo sometimes spares narrow periportal rim of
Fig. 1: Acute fatty liver of pregnancy. Detail of lobular parenchyma characterized by microvesicular steatosis and a small number of lymphocytes. (H&E)
Fibrin thrombi: o occasionally in hepatic sinusoids
Sometimes: o cholestasiso hepatocellular necrosiso extramedullary hematopoiesiso giant mitochondria3,4
Diagnosis In routinely stained sections:
o hepatocytes containing very fine fat droplets <1μm diameter:
may not be recognized as steatotic may appear as ballooned hepatocytes:
mimic hydropic swelling of liver cells in acute viral hepatitis:
may cause problems of diagnosis in the 10–20% of cases with a lymphoplasmacytic infiltrate and acidophil bodies3,5
Histochemical fat stains on frozen section:4o make diagnosis clear
Differential Diagnosis- Toxemia of Pregnancy- Drug Induced and Toxic Liver Injury- Steatohepatitis- Acute Hepatitis
Management Termination of pregnancy Supportive care for hepatic encephalopathy and extrahepatic
complications
Prognosis Has improved dramatically over past couple of decades
TOXEMIA OF PREGNANCY
Definition
Complication of pregnancy characterized by hypertension with proteinuria, peripheral edema and coagulation abnormalities (pre-eclampsia) and convulsions and coma (eclampsia). HELLP syndrome (hemolysis, elevated liver enzymes and low platelet count) can also occur in pre-eclamptic women.
Clinical Features 5% of pregnancies:
o incidence increased in: primigravidae acute fatty liver of pregnancy1
Generally during third trimester Hypertension induced or aggravated by pregnancy Association with:
o proteinuriao peripheral edema
Occasional coagulation abnormalities May be convulsions and coma2 If severe:
o hepatocellular dysfunction with elevated: serum transaminases alkaline phosphatase
o may lead to: liver failure two rare often fatal complications:
liver rupture preceded by subcapsular hematoma
infarction of liver3
Gross Pathology Diffuse, fine or blotchy hemorrhages over capsule and on cut
surface2,3 Intravascular coagulation due to endothelial injury and disruption
Histopathology Fibrin thrombi in:
o portal vesselso periportal sinusoids
Hemorrhage Hepatocellular necrosis
Special Stains and Immunohistochemistry Fibrin identified by:
o phosphotungstic acid–hematoxylin (PTAH) stainingo immunohistochemistry
Differential Diagnosis- Drug Induced and Toxic Liver Injury- Acute Fatty Liver of Pregnancy
LIVER INVOLVEMENT IN OTHER ORGAN SYSTEMS AND SYSTEMIC DISEASESGRANULOMASDefinitionGranulomas are seen in 3-15% of liver biopsies. Some causes include sarcoidosis, primary biliary cirrhosis, infections such as Q-fever, tuberculosis and fungi.
Clinical FeaturesEpithelioid Granulomas
In 3–15% of liver biopsies1,2Sarcoidosis
Incidence in established sarcoid 21–79% If clinical evidence of hepatic disease:
Lipogranuloma Focal response to rupture of lipid-laden hepatocytes
HistopathologyEpithelioid GranulomasSarcoidosis
Three broad categories of abnormalities besides granulomatous inflammation:3
o cholestatic (58%)o necroinflammatory (41%)o vascular (20%)
Histologic mimics of several other disorders, including: o primary biliary cirrhosiso primary sclerosing cholangitiso drug-induced liver diseaseo bile duct obstructiono viral hepatitis
Hepatic fibrosis (in 21%), including 6% with cirrhosis: o sometimes progressive liver disease
Epithelioid granulomas: o may be differing ageso typically:
greatest frequency in portal and periportal areas, often in clusters
heal with fibrosis: so often in same biopsy varying
numbers and degrees of: epithelioid cells inflammation giant cells scarring
o sometimes masses of granulomas and fibrosis (sarcoidoma):
raise clinical suspicion of neoplasm3Fibrin-ring Granulomas
Distinctive ring pattern Fibrin deposited circumferentially within or at margin Composed of:
o epithelioid cellso giant cellso neutrophilso central fat vacuole (Fig. 1)
Fig. 1: Q fever. Detail of lobular parenchyma with some steatosis and two fibrin ring granulomas. The granuloma is composed of a central fat vacuole, a layer of histiocytes and lymphocytes, a fibrin ring, and additional accumulation of inflammatory cells. (H&E)
Lipogranuloma Focal lesion May be:
o abundant: especially in alcohol-induced steatosis
o confluent Contains:
o macrophageso occasional lymphocyteso eosinophilso sometimes giant cells (Fig. 2)
Fig. 2: Hepatic steatosis in patient with alcohol abuse. The picture shows a mixture of macrovesicular and microvesicular steatosis and a lipogranuloma (upper right corner). (H&E)
Special Stains and ImmunohistochemistryEpithelioid Granulomas
Stains for microorganisms: o Ziehl–Neelseno silver methenamine for fungio immunostaining
Polarizing microscopy for inclusions X-ray microanalysis e.g. for:
o goldo bariumo silicon4
DiagnosisEpithelioid Granulomas
Careful histologic evaluation of: o granulomaso associated changes e.g.:
o coexists with amyloido intrahepatic cholestasis1
HistopathologyAmyloidosis
Amyloid: o homogeneous eosinophilic extracellular material (Fig.
1)
Fig. 1: Amyloidosis. Detail of lobular parenchyma with massive amyloid deposition in the space of Disse and corresponding marked atrophy of liver cell plates. (H&E)
o Amyloid deposition:o usually:
in hepatic artery branches along sinusoids in space of Disse:
leads to: atrophy of liver cell plates narrowing of sinusoids:
Fig. 2: Light chain deposition disease. Detail of lobular parenchyma with kappa chain deposition in the space of Disse. (Immunostain for kappa light chain)
DiagnosisAmyloidosis
Primary myeloma-associated (AL) amyloidosis vs reactive (AA) amyloidosis:
o cannot be reliably distinguished by topographic distribution pattern of deposits
LIVER PATHOLOGY IN ORGAN TRANSPLANTATIONLIVER TRANSPLANTDefinitionHepatic pathology associated with transplantation includes preservation injury, hyperacute, acute and chronic allograft rejection. Diseases such as hepatitis B, C, PBC, PSC, autoimmune hepatitis and tumors can also recur in the allograft.
Clinical FeaturesPreservation injury
Appears early: o first 2 weeks post transplant
Regresses spontaneously over several weeks1Humoral Rejection
Rare Within first few hours after transplantation Results in coagulative and hemorrhagic necrosis in a few days
Acute Rejection Most common form of rejection Mean incidence ≈50%2 Generally within first 3 weeks after transplantation:
o median onset 7–10 days3o late presentations usually related to decreased
immunosuppression4Chronic Rejection
History of acute cellular rejection Progressive cholestasis
Other Complications Following TransplantationBile Duct Stricture
At site of anastomosis or elsewhereHepatic Artery Thrombosis
Alone or in combination with portal vein thrombosis More common in children Results in infarction
Infections Common
Drug-induced Injury Several drugs in immunosuppressive therapeutic regimen capable
of causing hepatic damage May be difficult to incriminate a specific drug due to numerous
confounding featuresRecurrent Disease
Risk highest if: o neoplastico chronic viral hepatitis
HCV Recurrence Severe progressive cholestatic syndrome:
o incidence 2–10%Primary Biliary Cirrhosis
Antimitochondrial antibodies: o persisto do not correlate with disease recurrence
Neoplastic Disease Malignancies after liver transplantation comprise:
o hepatocellular carcinoma: recurrent5 or de novo6,7 mainly in recipients transplanted for chronic
viral hepatitis B and Co post-transplant lymphoproliferative disease
Primary or metastatic malignant tumorPreservation injury
Surgical necroses: o quite commono often observed in any surgical specimen26o clusters of neutrophils and scattered acidophil bodies
(Fig. 1)
Fig. 1: Surgical necroses consist of focal necrosis of hepatocytes and accumulation of clusters of neutrophil polymorphs. Originally described in specimens taken at the end of abdominal surgical interventions, they are now also recognized as a marker of ‘preservation damage’ in donor livers after revascularization during liver transplantation. (H&E)
Functional cholestasis: o bilirubin stasis in:
hepatocytes canaliculi27
o distinguish from cholestasis associated with: acute rejection drug toxicity hepatitis bile duct obstruction sepsis
Hepatocellular ballooning: o diffuse or centrilobular28,29o by itself, does not carry a bad prognosis29o possibly associated with bilirubin stasis
Centrilobular hepatocyte necrosis: o a more severe preservation injuryo due to hypoperfusiono a differential diagnostic problem because confluent
necrosis in: vascular complications drug-induced injury as poor prognostic sign in acute and chronic
allograft rejection30Acute Rejection (Fig. 2)
Fig. 2: Acute (cellular) rejection of liver allograft. Detail of portal tract showing dense mixed infiltrate (including lymphocytes, more immature lymphoid type cells, and eosinophils), mild endotheliitis (from center to lower right), and bile duct involvement (center left and center bottom). (H&E) (Courtesy of Prof. T Roskams, Leuven)
Triad of: o portal infiltrationo bile duct damage:o usually endotheliitis
Portal Infiltration Mixture of inflammatory cells:
o small lymphocytes predominateo larger lymphoid type cellso immunoblastso macrophageso plasma cellso neutrophilso eosinophils:
sometimes abundant and a helpful diagnostic feature31
o typically expands portal tracto may be focal and unevenly distributedo occasionally:
extends beyond limits of portal tract leads to portal–portal bridging necrosis32
Bile Duct Damage Bile ducts infiltrated by:
o lymphocyteso lymphoid-type cells (lymphocytic cholangitis)
Bile duct epithelial damage reflected in: o anisonucleosiso cytoplasmic vacuolizationo areas of cell stratification or occasional dropouto irregularities in duct outlines
Endotheliitis Portal or central veins Supraendothelial and subendothelial lymphocytes Endothelial damage Lifting off of endothelium from underlying layers Indicative of severe cellular rejection of:
o centrilobular veinso necrosis of centrilobular hepatocytes
Periportal extension of portal inflammatory infiltrate33A Less Frequent Form Of Cellular Rejection
Endothelial predominance: o isolated central venulitis in adult and pediatric liver
allograft recipients34,35o may result in:
perivenular fibrosis a veno-occlusive syndrome36
Grading Systems Several proposed:2
o to predict unfavorable clinical outcomeso consensus document33
Additional features less consistently present: o bilirubin stasiso some lobular inflammatory mononuclear infiltrateo if severe rejection:
centrilobular confluent parenchymal necrosis
Chronic Rejection (Fig. 3)
Fig. 3: Chronic ‘ductopenic’
rejection of liver allograft. Portal tract without bile duct and very sparse lymphocytic infiltration. (H&E)
Minimal diagnostic criteria: o bile duct atrophy/pyknosis:
affects majority of bile ducts with or without bile duct loss
o convincing foam cell obliterative arteriopathy, oro bile duct loss of >50% of portal tracts
Arteries with pathognomonic changes: o predominate in hilar regiono rarely in needle biopsy specimens
Considerable significance placed on damage and loss of small bile ducts
Changes mainly affect: o portal tracts:
loss of small bile ducts small branches of hepatic artery
o centrilobular areasEarly Bile Duct Changes
Uneven nuclear spacing Nuclear:
o enlargemento hyperchromasia
Interrupted epithelial lining of ductsEarly Arterial Lesions
Accumulation of subintimal, medial, and adventitial foamy macrophages
Late Bile Duct And Arterial Damage Mainly evaluated by extent of loss:
o bile duct loss when <80% of portal tracts contain bile ducts
o arterial loss when <77% of portal tracts contain hepatic artery branches17
Early lesions In Centrilobular Area Subendothelial and perivenular mononuclear inflammation of
‘Transitional Hepatitis’ Sometimes difficult to distinguish from viral hepatitis May occur during evolution to late stages37
Late Chronic Rejection Severe (bridging) perivenular fibrosis At least focal central–central or central–portal bridging Occasional obliteration of terminal hepatic venules
Other complications following transplantationBile Duct Strictures
Histologic features of any biliary obstructionDrug-induced Injury
Azathioprine: o associated with:
sinusoidal congestion centrilobular necrosis38
Ciclosporin: o may cause:
canalicular bilirubin stasis hepatocyte ballooning vacuolization of bile duct epithelial cells39
Recurrent Disease Some have histopathologic features that overlap with those in:
May cause: o acute and chronic hepatitiso cirrhosiso minimal histologic changes (carrier state)o in a minority of cases, fibrosing cholestatic hepatitis:18
perisinusoidal bands of fibrosis around plates of ductular-type epithelium
prominent bilirubin stasis ground glass hepatocytes hepatocellular ballooning with
cell loss mild mixed inflammatory
reaction18HCV Recurrence
As defined by histologic injury almost universal Sometimes severe graft injury resulting in graft loss20,41,42
Primary Biliary Cirrhosis Liver biopsy:
o gold standard for diagnosis of recurrence:43 most helpful features:
florid bile duct lesions epithelioid granulomas
granulomatous cholangitis also observed in chronic viral hepatitis C44
less helpful features that may occur in chronic hepatitis C and allograft rejection:
portal lymphoid aggregates ductopenia
other useful features: ductular reaction progressive cholate stasis
(including copper deposition) suggested early marker:
plasma cells in portal infiltrate45Primary Sclerosing Cholangitis46
Requires well-defined cholangiographic and histologic criteria42 Features resemble those of complications of transplant procedure
Autoimmune Hepatitis Based on clinical, biochemical, serologic, and histologic criteria:43
o portal and periportal inflammation (interface hepatitis) containing plasma cells47
Diagnosis Percutaneous liver biopsies:
o obtained when symptoms of deterioration of liver function
Protocol biopsies: o biopsies obtained on planned schedule irrespective of
liver chemistry48,49 Fine needle aspiration biopsy:
o may be adequate in experienced hands50 Several pathologic conditions may coexist in liver allograft such as:
o drug toxicityo viral hepatitiso disease recurrenceo rejection
Preservation injury Time zero biopsies:
o for evaluation
o obtained at transplantation directly after revascularization of graft51
Chronic Rejection Diagnosis based on combination of clinical, radiological,
laboratory, and histopathologic findings Defining features not uniformly present:
o bile duct loss can occur without arteriopathyo arteriopathy can occur without bile duct losso severe (bridging) centrilobular fibrosis may be present
without significant bile duct loss or obliterative arteriopathy
o may be late features of one component (e.g. bile duct loss) and early features of another component (e.g. perivenular necrosis)17
Working formulation for histopathologic staging and reporting of chronic liver allograft rejection proposed:
o early chronic rejection: if no more than one of the target structures
shows late changeso late chronic rejection:
at least two or more target structures show late changes
o may be duct destructiono lymphocytic infiltration of duct epitheliumo mild portal inflammation
Early biopsies (<35 days): o less bile duct damageo marked hepatocellular apoptosis3
Other lesions: o endotheliitiso siderosiso veno-occlusive disease4
Chronic GVHD Similar to acute GVHD, but more severe Dense portal infiltration:
o sometimes: periportal extension interface hepatitis
Lobular changes include: o bilirubin stasiso apoptotic bodies
When advanced: o ductopenia5o cholate stasiso progressive periportal fibrosiso cirrhosis
Differential Diagnosis- Acute Hepatitis- Drug Induced and Toxic Liver Disease- Cholestasis
Acute Hepatic GVHD Picture in early biopsies (<35 days) easily confused with viral
hepatitis C
ECHINOCOCCUS CYST (Hydatid Cyst)DefinitionInfection of the liver by the larval or cystic stage of echinococcus tapeworms. The most common is E. granulosus, but the most aggressive is E. multilocularis.
Clinical FeaturesEchinococcus granulosus
Most frequent cause of echinococcus cysts: Commonly communication with biliary tract and superimposed
infection1 May rupture:
o into peritoneal cavity and result in: fatal anaphylactic reaction formation of innumerable small granulomas
grossly resembling peritoneal tuberculosis: fragments of germinal
membrane or scolices in center points indicate diagnosis
o inside gallbladdero through diaphragm into pleural space and lung
Echinococcus multilocularis Compared with E. granulosus:
o less commono more aggressive clinical disease
Pathogenesis Result of hydatid disease caused by larval or cystic stage of
Echinococcus tapewormsEchinococcus granulosus
Adults in dogs and jackals in all continents2 Ingested eggs hatch into larval oncospheres, which enter liver by
portal vein
Gross PathologyEchinococcus granulosus
Hepatic cyst (Fig. 1):
Fig. 1: Echinococcosis of the liver.
o one or more in 75% of infected individualso slow growtho typically sphericalo may be >30cm diametero usually right lobeo may be multiple, involving all lobes3,4
DefinitionHepatic abscesses are due to the following in descending order: biliary obstruction and infection, systemic bacteremia, direct extension from contiguous infection, trauma and pylephlebitis. Tuberculous and anaerobic infections have been increasing while amebic and culture negative cases have been decreasing.
Clinical Features Mortality rate 10–20%1,2 In US usually:
o older adults, oro HIV-infected or other immunocompromised young
individualsAmebic Abscess
Usually adult3,4
Pathogenesis In past usually:
o amebic, oro secondary to pylephlebitis
Today in US: o usually due to enteric bacteria
o increasing number of tuberculous ‘abscesses’5,6 in immunocompromised
Predisposing factors, in descending order of frequency: o biliary tract obstruction/infectiono systemic bacteremiao direct extension from contiguous infectiono penetrating or nonpenetrating traumao pylephlebitis7,8
Specific causes: o secondary bacterial infection of metastatic tumor
Fig. 1: Large liver abscess surrounded by a thick fibrous wall.
May be multiple: o ≈50% of pyogenic abscesseso ≈25% of amebic abscesses13
Communication between abscess and intrahepatic biliary system slightly <50% of cases14
Amebic Abscess Usually:
o singleo right sidedo close to liver dome15 (Fig. 2)
Fig. 2: Amebic abscesses occupying most of the right lobe of the liver. Three distinct lobules are seen. (Courtesy of Dr RA Cooke, Brisbane, Australia; from Cooke RA, Stewart B: Colour Atlas of Anatomical Pathology. Edinburgh, Churchill Livingstone, 2004).
Greater tendency for multicentricity if immunocompromised Necrotic center:
o usually contains odorless, pasty, chocolate brown fluid May be: