PRESENTED BY: DR. KALPAJYOTI BHATTACHARJEE SAIVARY GLAND TUMORS
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PRESENTED BY:DR. KALPAJYOTI BHATTACHARJEE
SAIVARY GLAND TUMORS
Introduction
Epidemiology
Etiology
Histogenesis
Morphogenesis
Genetics
Classification
Benign tumours
CONTENTS
Tumors of the salivary glands are:
-Most heterogeneous group of tumors.
-Greatest diversity of morphologic features.
Relatively uncommon.The majority of these neoplasms are benign 80% and only 20%
are malignant.
The various types of salivary gland tumors are best
distinguished by their histologic patterns.
INTRODUCTION
A broad morphologic spectrum exists between different tumor types and sometimes even within an individual tumor mass.
Certain neoplastic processes have obvious histologic, functional, immunohistochemical, and/or ultrastructural markers that allow pathologists to assemble nonologic groupings that function somehow like a taxonomic system.
The inherent complexity, together with the relative infrequency of salivary gland tumors, contributes to a situation in which diagnostic dilemmas are almost inevitable and unfortunately occur all too frequently.
uncommon neoplasms2%-6.5% of all head and neck neoplasms. Global annual incidence varies from 0.4-13.5 cases per 100000
people.Most salivary gland tumors originate in the parotid glands
(64%-80%), malignancy (15%- 32%).7-11% occur in the submandibular glands, malignancy (37%-
45%). less than 1% in the sublingual glands, malignancy (70%-90%)
EPIDEMIOLOGY
9%-23% in the minor glands. Benign tumors account for 63% to 78% of all salivary gland
neoplasms. Most common benign tumor: Pleomorphic adenoma-53%-77% of all cases occurs in parotid glands.Warthin’s tumor- 6%-14% of all casesMost common malignancy- Mucoepidermoid carcinoma.
Most common minor salivary gland tumor site: Palate, (42%-54%).
The proportion of malignant tumors varies significantly by site and is the greatest in the sublingual glands, tongue, floor of the mouth, and retromolar area.
Most common among children: Mucoepidermoid carcinoma.
Rule of 80’s:
-80% of parotid tumors are benign
-80% of parotid tumors are Pleomorphic adenomas
-80% of salivary gland Pleomorphic adenomas occur in the
parotid
-80% of parotid Pleomorphic adenomas occur in the superficial
lobe
-80% of untreated Pleomorphic adenomas remain benign
Viruses- EBV, CMV, Polyoma virus, Ionizing radiation. Increased occupational risks- asbestos, nickel compounds or
silica dust.Employment in the woodworking, rubber industries and beauty
saloons.Lifestyle- Warthin’s tumors showed a strong association with
cigarette smoking. Endogenous hormones.
ETIOLOGY
Definition: Cell of origin for a neoplasm rather than the
developmental process underlying the tumorThe formation or development of tissue from the
undifferentiated cells of the germ layers of the embryo.
HISTOGENESIS
Basal cells of both excretory and intercalated duct responsible for differentiation of functional units.
BASAL RESERVE CELL THEORY
Theories …….
PLURIPOTENT UNICELLULAR RESERVE CELL THEORY
BatsakisBasal cells of excretory duct responsible for development of all
remaining salivary gland units.
The outer (basal) layer of cells give rise to the inner (luminal)
layer.
Eversole in 1971, refined by Batsakis and colleagues.2 Cells- excretory duct reserve cells intercalated duct reserve cells.- were presented as the hypothetical cells of origin for salivary gland
neoplasm.
SEMIPLURIPOTENT BICELLULAR RESERVE CELL THEORY
From Excretory duct - Mucoepidermoid carcinoma, Primary SCC and Salivary duct carcinoma From Intercalated duct- Pleomorphic and monomorphic adenoma Polymorphous low grade adenocarcinoma, Basal cell adenocarcinoma (BCA), Adenoid cystic carcinoma (AdCC) and Acinic cell carcinoma (ACC).
Adenocarcinoma, not otherwise specified (NOS) (AdC NOS) - arise from either of these reserve cells.
carcinoma ex pleomorphic adenoma - uncertain histogenesis.
Myoepithelial cells were responsible in part for the wide histologic variation of these neoplasms.
Acinar secretory cell play a minimal role in the parencymal renewal and thus, was incapable of a significant role in tumor induction.
Differentiated cells at all levels of the gland, including acinar and basal cells, are capable of cell division and metaplastic alterations.
MULTICELLULAR THEORY
Taxonomic classification of salivary gland tumors
Definition: The process of differentiation inherent in the neoplasms and
the resulting histopathology characteristic for that particular tumor.
The evaluation and development of form, as the development of the shape of a particular organ or part of a body or developments undergone by individuals who attain the type to which the majority of the individuals of the species approximate.
MORPHOGENESIS
Salivary gland
Luminal (acinar and ductal cells)
Abluminal (myoepithelial and basal cells).
Ducto-acinar concept:
Patterns of tumor differentiation reflect the bilayered cells composed of luminal or acinar cells and outer basal and/or myoepithelial cells.
Cell differentiation results in three basic models of benign or malignant salivary gland neoplasms.
1) In one form of differentiation, tumor cell population results in a dual population that combines recognizable luminal and/or acinar cells with myoepithelial and/or basal cells
2) A second pattern results primarily in luminal/glandular cells that resemble to some extent normal duct epithelial and/or acinar cells
3) The third process produces tumor cells resembling normal myoepithelial and/or basal cells.
Salivary ducto-acinar unit showing potential fordifferentiation of three salivary gland tumour pathways
Myoepithelial cells :
Physiologically and functionally modified epithelial cells
located between the luminal cells and basement membrane.
Stellate shaped with cytoplasmic processes embracing the
acini, or spindle shaped surrounding the intercalated ducts.
Possess a dual epithelial and smooth muscle phenotype.
Produce an extracellular matrix.
Exert an anti-invasive effect in a neoplasm promoting
epithelial differentiation, secreting proteinase inhibitor and
suppressing angiogenesis
P-63, high molecular weight cytokeratin (CK-14) are positive for myoepithelial cells.
Other myoid markers are calponin, actin, myosin, S-100 and Glial Fibro Acidic Protein (GFAP).
CD117/c-kit is negative in the normal salivary gland cells, however, is interestingly positive in the luminal (glandular) cells of various types of salivary gland tumors.
Luminal cells:Readily highlighted by immunostaining for cytokeratin,
carcinoembryonic antigen (CEA), and epithelial membrane antigen (EMA).
Abluminal cells :Basal cells that differs ultastructurally from myoepithelial cells
in the absence of myofilaments. Maintain the capacity of multidirectional differentiation and
play an important role in regeneration and metaplastic changes. Immune reactive for p-63 and high molecular weight
cytokeratin.
Pleomorphic Adenoma
Adenoid cystic carcinoma
Mucoepidermoid carcinoma
Monomorphic adenomas
1) Chromosomes 3p21, 8q12 and 12q13-15 rearrangements and the PLAG-1 and HMGI-C genes in pleomorphic adenomas
2) Translocations of chromosomes 11q21 and 19p13 in both Warthin tumour and mucoepidermoid carcinoma.
3) Structural and molecular alterations at 6q, 8q, 12q in adenoid cystic and carcinoma ex-pleomorphic adenoma.
4) Elevated HER-2 gene expression and gene amplification in mucoepidermoid, salivary duct and adenocarcinomas
GENETICS IN SALIVARY GLANDS NEOPLASM
CLASSIFICATION OF SALIVARY GLAND TUMORS
Sebaceous adenoma
Ductal papilloma
-Inverted ductal papilloma
-Intraductal papilloma
-Sialadenoma papilliferum
Cystadenoma
-Papillary cystadenoma
-Mucinous cystadenoma
1. WORLD HEALTH ORGANIZATION, 1991
AdenomasPleomorphic adenoma
Myoepithelioma
Basal cell adenoma
Warthin tumor
(adenolymphoma)
Oncocytoma (oncocytic
adenoma)
Canalicular adenoma
Carcinomas
Acinic cell carcinoma
Mucoepidermoid carcinoma
Adenoid cystic carcinoma
Polymorphous low-grade
adenocarcinoma
Epithelial-myoepithelial carcinoma
Basal cell adenocarcinoma
Sebaceous carcinoma
Papillary cystadenocarcinoma
Mucinous adenocarcinoma
Oncocytic carcinoma
Salivary duct carcinoma
Adenocarcinoma
Malignant myoepithelioma
Carcinoma in pleomorphic
adenoma
Squamous cell carcinoma
Small cell carcinoma
Undifferentiated carcinoma
Other carcinomas
Nonepithelial tumors
Malignant lymphomas
Secondary tumors
Unclassified tumors
Tumor-like lesions Sialadenosis
Oncocytosis
Necrotizing sialometaplasia (salivary gland infarction)
Benign lymphoepithelial lesion
Salivary gland cysts
Chronic sclerosing sialadenitis of the submandibular gland (Küttner tumor)
Cystic lymphoid hyperplasia in acquired immunodeficiency syndrome
Malignant epithelial tumors Acinic cell carcinoma Mucoepidermoid carcinoma Adenoid cystic carcinoma Polymorphous low-grade
adenocarcinoma Epithelial-myoepithelial carcinoma Clear cell carcinoma not otherwise
specified Basal cell adenocarcinoma Sebaceous carcinoma Sebaceous lymphadenocarcinoma Cystadenocarcinoma Low-grade cribriform
cystadenocarcinoma Mucinous adenocarcinoma
2. WHO HISTOLOGIC CLASSIFICATION, 2005
• Oncocytic carcinoma• Salivary duct carcinoma• Adenocarcinoma, not otherwise
specified• Myoepithelial carcinoma• Carcinoma ex pleomorphic
adenoma• Carcinosarcoma• Metastasizing pleomorphic
adenoma• Squamous cell carcinoma• Small cell carcinoma• Large cell carcinoma• Lymphoepithelial carcinoma• Sialoblastoma
Benign epithelial tumors
Pleomorphic adenoma
Myoepithelioma
Basal cell adenoma
Warthin tumour
Oncocytoma
Canalicular adenoma
Sebaceous adenoma
Lymphadenoma
-Sebaceous
-Nonsebaceous
• Ductal papillomas
-Inverted ductal papilloma
-Intraductal papilloma
-Sialadenoma papilliferum
• Cystadenoma
Soft-tissue tumors
Hematolymphoid tumors
Secondary tumors
Name suggested by Willis.Most common neoplasm of salivary gland
tumor.Benign neoplasm- consisting of cells
exhibiting the ability to differentiate to epithelial (ductal and nonductal) cells and mesenchymal (chondroid, myxoid, osseous) cells.
Other names: Branchioma, enclavoma, teratoma, cyindroma, myxochondrocarcinoma.
Salivary gland tumor origin: EPITHELIAL
PLEOMORPHIC ADENOMA/ MIXED TUMOR
Shows cytogenic abnormalities in chomosomes- 12q13-15.
Putative pleomorphic adenoma gene(PLAG1) has been mapped to chromosomes 8q12.
Most common tumor.Rate of occurance: 60-70%- parotid glands 40-60%- submandibular glands 40-70%- minor salivary glands seldomly- sublingual glandsAge: 30-50 yearsSex: female> male – 3:1 – 4:1 In parotid- presents in the lower lobe of the superior
lobe as a mass over the angle of the mandible, below and infront of the ear.
Clinical feature:
Clinical presentation: painless, slow growing, firm mass, initially small in size and begins to increase in size.
Initially movable but with continued growth become more nodular and less movable.
Recurrent tumor- multinodular, fixed on palpation.
Palate – intraorally common site.Seldom ulcerated- unless secondarily
traumatized.
Slowly growing tumor of The parotid gland.
Tumor of the submandibular gland
Firm mass of the hardpalate lateral to the midline.
Tumor of the pterygomandibular area.
MRICT SCAN
INVESTIGATION
Benign mixed tumor demonstrating a firm, whitish tan, well-encapsulated mass
The cut surface of the tumor is tan-colored and interspersed with brown areas. Glossy quality of the tumor.
GROSS PATHOLOGY
HALLMARK: Morphologic Diversity.Charecterized by- Variable, Diverse, Structural & histologic
patterns. It demonstrate glandular epithelium and mesenchyme like
tissue and the proportion of each component varies widely.Typically a well-circumscribed encapsulated tumorThe epithelium often forms ducts and cystic structures or may
occur as islands or sheets of cells , anastomosing cords and foci of Keratinizing squamous cells and spindle cells .
MICROSCOPIC FEATURES
Foote and Frazell (1954) categorized PA into:a) Primarilly myxoid (36%)b) Myxoid and cellular component in equal
proportions (30%)c) Predominantly cellular (22%)d) Extremely cellular (12%)
Myoepithelial cells are major component of PA.Have variable morphology- sometimes appearing
as angular or spindled, some with eccentric nucleus resembling plasma cells.
Are responsible for characteristic mesenchyme like changes.
Vacuolar degeneration of myoepithelial cells can produce a chondroid appearance.
the stroma exhibits areas of an eosinophilic hyalinized change,
fat or osteoid also is seen.
Mixed tumor with prominent cartilaginous differentiation and surrounding ducts and myoepithelial cells.
Plasmacytoid myoepithelial cells.
Ductal structures (left) with associated myxomatous background (right) .
Chondroid material (right) with adjacent ductal epithelium and myoepithelial cells
Cellular mixed tumor :
Because of its extreme cellularity, this tumor may be mistaken for a malignant tumor
Pleomorphic adenoma showing bone forming by osseous metaplasia in stroma.
Many of the ducts and myoepithelial cells are surrounded by a hyalinized. Eosinophilic background alteration.
Pleomorphic adenoma showing afocus of mucous metaplasia.
Focal squamous differentiation with keratinization is seen amidst complex glandular structures.
Polymorphous low grade adenocarcinoma, PLGA
Adenoid cystic carcinoma, AdCC
Epithelial myoepithelial carcinoma, EMC
Squamous cell carcinoma, SCC
Mucoepidermoid carcinoma, MEC
Differential Diagnosis
Surgical excision
Superficial parotidectomy with preservation of the facial nerve
Local enucleation should be avoided - resulting in seeding of
the tumor bed.
Deep lobe of the parotid- total parotidectomy is usually
necessary also with preservation of the facial nerve.
TREATMENT AND PROGNOSIS
Submandibular tumors - Total removal of the gland with the tumor.
Malignant degeneration is a potential complication, resulting in
a carcinoma ex pleomorphic adenoma.
The risk of malignant transformation is probably small, but it
may occur in as many as 5% of all cases.
Term used by Sheldon in 1943.
Uncommon- <1% of all salivary gland tumors.
it represents “one-sided” varient at the opposite end of the
spectrum from Pleomorphic adenoma
Defined as a tumor composed entirely or predominantly of
myoepithelial cells.
MYOEPITHELIOMA
Clinical Features
Similar to Pleomorphic Adenoma
Seen among adults
equal frequency in males and females.
Site: parotid most common, palate most common intraorally.
typically present as slowly enlarging, asymptomatic masses.
Masses usually 1 to 5 cm in diameter.
Well encapsulated.Composed exclusively or almost exclusively of
neoplastic myoepithelial cells.Microscopically, the neoplastic cells are arranged in sheets,
irregular collections, nests, interconnecting trabeculae, or ribbons, giving solid, myxoid, reticular, microcystic, and cribriform growth patterns.
The component cells may be spindle shaped, plasmacytoid , clear, polygonal, epithelioid, basaloid, or oncocytic
Histologic Features
A, The typical plasmacytoid pattern contains eccentric nuclei and abundant eosinophilic cytoplasm.B, The spindle cell pattern is made up of a uniform population of interlacing bundles of spindle cells with moderate amounts of light eosinophilic cytoplasm.
A B
C, The reticular type is composed of numerous interconnecting ribbons of myoepithelial cells. D, The clear cell variant is composed of a somewhat uniform sheet of cells with a moderate amount of clear cytoplasm
C D
Myoepithelial carcinoma
Pleomorphic adenoma
Nodular fasciitis
solitary fibrous tumor
fibrous histiocytoma
leiomyoma
Schwannoma
Differential Diagnosis
Treatment
complete excision with a rim of normal surrounding tissue.
Primary Salivary Tumors with Myoepithelial Cell Participation
Benign
Pleomorphic adenoma
Myoepithelioma
Basal cell adenoma
Malignant
Adenoid cystic carcinoma
Polymorphous low-grade adenocarcinoma
Epithelial-myoepithelial carcinoma
Myoepithelial carcinoma (malignant myoepithelioma)
Carcinoma ex pleomorphic adenoma
Benign tumor composed of large epithelial cells known as
oncocytes- with granular eosinophilic cytoplasm and a large
number of atypical mitochondria.
It is a rare neoplasm, representing approximately 1% of all
salivary tumors.
Except salivary gland oncocytes are also seen thyroid,
parathyroid, kidney.
ONCOCYTOMA(ONCOCYTIC ADENOMA/ OXYPHILIC ADENOMA/ ACIDOPHILC ADENOMA)
Age: predominantly a tumor of older adults, 50-80 years.
Sex: slight female predilection
Site: primarily in the major salivary glands, parotid gland- 85% to
90%
Oncocytomas- minor salivary glands are exceedingly rare.
C/P- The tumor appears as a firm, slowly growing, painless mass
that rarely exceeds 4 cm in diameter.
Parotid oncocytomas usually are found in the superficial lobe and are
clinically indistinguishable from other benign tumors.
bilateral tumors can occur.
CLINICAL FEATURES
Gross appearance of oxyphilic adenoma. The tumor is well circumscribed, solid, and light brown.
well-circumscribed tumor that is composed of sheets of large polyhedral cells (oncocytes), with abundant granular, eosinophilic cytoplasm.
Arranged in sheets, nests or cords which form an alveolar or glandular pattern
cells have centrally located nuclei that can vary from small and hyperchromatic to large and vesicular.
little stroma is present, usually in the form of thin fibrovascular septa.
lymphocytic infiltrate
Histopathologic Features
Granularity of the cells is created by an overabundance of mitochondria
These granules also can be identified on light microscopic examination with a phoshotungstic acid -hematoxylin (PTAH) stain.
The cells also contain glycogen- periodic acid-Schiff (PAS) technique
variable numbers of cells with a clear cytoplasm. – clear cell oncocytoma.
Oncocytoma is composed of a sheet of oncocytic cells with uniform, predominantly centrally located nuclei and abundant eosinophilic
Clear cell oncocytoma composed predominantly of sheets of clear cells, usually with focal areas containing typical oncocytic cells .
Differential diagnosis
Mucoepidermoid carcinoma (MEC)
pleomorphic adenoma (PA)
prominent oncocytic metaplasia may also be seen in
-epithelial-myoepithelial carcinoma
-myoepithelioma
-basal cell adenoma (BCA)
-acinic cell carcinoma (ACC)
surgical excision
The prognosis after removal is good with a low rate of
recurrence.
Oncocytomas of the sinonasal glands can be locally aggressive
and have been considered to be low-grade malignancies
TREATMENT AND PROGNOSIS
Second most common tumor in salivary glands.
First recognized by Albrecht in 1910.
Quoted by Ellis and Auclair in 1991
Later described by Warthin in 1929
Occurs exclusively in the parotid gland.
WARTHIN'S TUMOR(PAPILLARY CYSTADENOMA LYMPHOMATOSUM, ADENOLYMPHOMA)
Accepted theory: Tumor arises in the salivary gland tissue entrapped within paraparotid or intraparptid lymph nodes during embryogenesis.
According to Allerga, it is most likely delayed hypersensitivity diseases, lymphocytes being an immune reaction to the salivary ducts which undergo oncocytic change.
According to Hsu and coworkers, lymphoid component of the tumor is an exaggerated secretory immune response.
Histogenesis
studies that have found cytogenetic abnormalities in the
epithelial component
Smokers- eight fold greater risk for Warthin’s tumor than do
nonsmokers.
Epstein-Barr virus also has been implicated in the pathogenesis
Clinical FeaturesAppears as a slowly growing, painless, nodular mass of the parotid
gland
firm or fluctuant to palpation.
occurs in the tail of the parotid near the angle of the mandible
occur bilaterally, 5% to 14% of cases.
bilateral tumors do not occur simultaneously but are metachronous
(occurring at different times).
In rare instances, submandibular gland or minor salivary glands.
lymphoid component is often less pronounced in these extraparotid
sites.
Age: 60-80 years
Lower in blacks than in whites
Sex: male>female predilection
Warthin tumors have been associated with cigarette smoking.
This association with smoking also may help explain the frequent
bilaterality of the tumor because any tumorigenic effects of
smoking might be manifested in both parotids.
Gross appearance of Warthin tumor of parotid gland. The presence of multiple large cystic spaces is characteristic of this lesion.
Histopathologic FeaturesThe tumor is composed of a mixture of ductal epithelium and a
lymphoid stroma.
Exhibit cyst formation, with projection into the cystic space and a
lymphoid stroma showing germinal centers.
Arranged in two layers.
The inner luminal layer consists of tall columnar cells, finely
granular eosinophilic cytoplasm with centrally placed, palisaded and
slightly hyperchromatic nuclei.
The outer layer cells are oncocytic triangular and occasionally
fusiform basaloid cells.
Focal areas of squamous metaplasia or mucous cell prosoplasia
may be seen.
Eosinophilic coagulum present within cystic spaces.
Lymphoid stroma- germinal center formation.
Warthin’s tumor showing papillary cystic tumor with dense lymphoid stroma
The papillae and glands are typically lined by columnar oncocytic luminal cells in which the nuclei are often polarized towards the lumen. Beneath the luminal cells is a layer of basal cells, which are sharply demarcated from the underlying lymphoid stroma.
Occasionally, foci of prominent squamous metaplasia (left inset) and mucinous metaplasia (right inset) may be seen within this tumor
Differential diagnosis
Oncocytic papilary cystadenoma.
lymphoepithelial cystic lesions such as
simple benign lymphoepithelial cyst (unrelated to AIDS),
AIDS-related parotid cyst,
lymphoepithelial sialadenitis,
MALT (mucosa-associated lymphoid tissue)
Treatment and Prognosis
Surgical removal
local resection with minimal surrounding tissue
superficial parotidectomy to avoid violating the tumor capsule .
6% to 12% recurrence rate
Malignant Warthin tumors (caretnoma ex papillary cystadenoma
Iymphomatosum) have been reported but are exceedingly rare.
Neoplasm of uniform population of basaloid epithelial cells
arranged in solid, trabecular, tubular or membranous pattern.
1st reported by: Kleinsasser and Klein in 1967
Histological source: Intercalated duct or reserve cell.
Monomorphic adenomas- term should be avoided. Because
ultrastructural and immunohistochemical studies have shown that
basal cell adenomas are not necessarily composed of only one
cell type but sometimes of a combination of salivary ductal
epithelium and myoepithelial cells.
BASAL CELL ADENOMA
Clinical features:
Age: middle aged- 57.7 yearsSex: F:M=2:1Site: Parotid – 75%- superficial lobe. Intraorally- Upper lip & Buccal mucosa.C/p- Slowly growing, freely movable mass, less than3cm in
size- firm in consistency which may be cystic and compressible.
One subtype, Membranous BCA- Appears hereditary.Often occurs in combination with skin appendage tumors- Dermal
Cylindromas & Trichoepitheliomas.Multiple bilateral tumors- Because these tumors often bear a
histopathologic resemblance to the skin tumors- Dermal analogue tumors.
Gross pathology:
Round to ovoid, well-circumscribed, with smooth surface capsule, firm in consistency- similar to lymph node.
Membranous Basal cell adenoma- Multinodular.Cut surface- homogenous, solid appearance that may be
interrupted by cysts of varying sizes, filled with brown/ red mucinous or blood, gray white to pink red or brown in color.
Histological features:Basal cells that make up this lesions are uniform and
regular.2 morphological forms: 1) small cells- scanty cytoplasm, round deeply basophilic
nucleus. 2) large cells- amphophilic to eosinophilic cytoplasm,
ovoid pale staining nucleus. larger (pale) cells predominates with the small (daker)
cells, located in the peripheral portion of the epithelial tumor nests, cords or islands.
4 morphologic pattern: a) solid b) trabecular c) tubular d) membranous.
2 consistant features seen:Sharp demarcation between the neoplastic
epithelial cells and the surrounding connective tissue
Palasiding of peripheral cuboidal or slightly columnar cells that accentuates epithelioconnective tissue interface.
Solid type :
Large sheets & broad bands of basaloid cells demonstrating palasiding pattern, Cells demarcated from the connective tissue stroma by a basement membraneInner portion- Epithelial cells-parallel to basal cells- tends to produce scattered whorled eddies.Eddies mature into squamous cells- produce keratin to give appearance of keratin pearl.Detail of a squamous differentiation frequently found in the solid variant (inset).
(a)Clinical examination: Small nodule behind the left ear. (b)basaloid cells in nests sheets and trabeculae (PAP stain; ×100). (c) peripheral palisading of cells (red arrows) and bare nuclei in
background (PAP, x400)); (d) basement membrane material around cell clusters (green arrows) (PAP,
x400
Trabecular type :
Narrow epithelial islands forming an interconnecting cord-like architecture- reticular pattern.
Tubular type.
Prominent multiple duct-like structures with intraluminal eosinophilic secretion occurs in conjugation with trabecular pattern to form a trabeculotubular patternLeast common
Inner cuboidal ductal cells
Outer layer of basaloid cells 2
cells
Membranous type.
Presence of thick, hyaline, basement membrane like material surrounds large lobules. This material is also present within the epithelial nests forming coalescing, hyaline droplets.Epithelial islands produce JIGSAW PUZZLE PATTERNHyaline material- PAS STAIN POSITIVE.
Differential diagnosis:
Mixed tumors Adenoid cystic carcinomaCutaneous basal cell carcinomaBasal cell adenocarcinoma
Treatment and Prognosis
similar to that of pleomorphic adenoma, complete surgical removal
Recurrence is rare
membranous subtype has a 25% to 37% recurrence rate
malignant counterpart - basal cell adenocarcinoma
A number of salivary gland tumors can be characterized
microscopically by a papillomatous pattern.
The sialadenoma papilliferum, intraductal papilloma , and
inverted ductal papilloma are three rare salivary tumors
that also show unique papillomatous features.
viral - human papillomavirus
DUCTAL PAPILLOMAS (SIALADENOMA PAPILUFERUM; INTRADUCTAL PAPILLOMA; INVERTED DUCTAL PAPILLOMA)
on occasion, the common squamous papilloma of the oral
mucosa will arise at the site where a minor salivary gland
merges with the surface epithelium.
Because of this location, such squamous papillomas also
contain scattered mucous cells within the exophytic
papillary growth, and these lesions - "ductal papillomas”
Clinical Features
Sialadenoma Papilleferum- minor salivary glands, especially on the palate,
among major glands- parotid gland. older adults., M:F-1.5:1
Biphasic growth pattern exophytic papillary and endophytic components. exophytic, papillary surface growth that is clinically similar to the common
squamous papilloma.
Intraductal Papilloma- ill- defined lesion that often has been confused with
the papillary cystadenoma.
occurs in adults, minor salivary glands- lower lip
No gender predilection
c/p- submucosal swelling, appears to arise from excretory duct.
Inverted Ductal Papilloma- rare tumor that has been described
only in the minor salivary glands of adults.
Site: most common lower lip and mandibular vestibule
Appears to arise from excretory duct near mucosal surface.
asymptomatic submucosal nodule, may show a pit or
indentation in the overlying surface mucosa.
Histopathologic Features
Sialadenoma papilliferum is somewhat similar to the squamous
papilloma , exhibiting multiple exophytic papillary projections that are
covered by parakeratotic stratified squamous epithelium.
This epithelium is contiguous with a proliferation of papillomatous
ductal epithelium found below the surface and extending downward into
the deeper connective tissues.
Sialadenoma papilliferum demonstrating the typical exophytic papillary surface and deeper ductal components.
Multiple ductal lumina are formed, which characteristically are lined
by a double- rowed layer of cells consisting of a luminal layer of tall
columnar cells and a basilar layer of smaller cuboidal cells.
These ductal cells often have an oncocytic appearance. infiltrate of
plasma cells, lymphocytes, and neutrophils is present.
The bland surface squamous epithelium communicates with the underlying columnar epithelium lining the ductal structures.
Sialadenoma papilliferum . Low-power view showing a papillary surface tumor with associated ductal str uctures in the superficial lamina propria.
Sialadenoma papilliferum. High-power view of cystic areas lined by papillary, oncocytic epithelium
Differential diagnosisSquamous papillomaCondyloma acuminatumPapillary cystadenomaVerrucous carcinomaMucoepidermoid carcinoma
Inverted ductal papilloma is composed primarily of a proliferation of squamoid
epithelium with multiple thick, bulbous papillary projections that fill the ductal
lumen.
Well defined tumor mass within the lamina propria that has an epidermoid
appearance.
Basaloid and squamous cells are arranged in thick, bulbous proliferation that
project in papillary configuration into a luminal cavity.
Pushing interface with the connective tissue stroma of the lamina propria and the
submucosa.
Lumina is often narrow.
Small microcysts within the epithelium is evident.
Inverted ductal papilloma.
This tumor is continuous with the overlying surface epithelium and grows in an inverting pattern, forming a smooth-edged, broad-based mass. It is composed of immature squamous or basaloid epithelium
In addition, numerous mucinous goblet cells are often intermixed with the basaloid and squamous cells.
Intraductal papilloma exhibits a dilated, unicystic structure
that is located below the mucosal surface.
Papilloma appears to arise in the duct system more distant from
the mucosal surface.
Cyst wall is lined by a single or double row of cuboidal or
columnar epithelium, which has multiple arborizing papillary
projections into the cystic lumen.
Extending into the lumen of the cystic space are fronds of columnar epithelium supported by a central fibrovasacular core.
Treatment and Prognosis
conservative surgical excision.
Recurrence is rare.
Transformation of ductal and acinar cells to oncocytes.
Uncommon before the age of 50
oncocytes are a common finding in the salivary glands
Oncocytosis refers to both the proliferation and accumulation of
oncocytes within salivary gland tissue.
It may mimic a tumor both clinically and microscopically.
Considered to be a metaplastic process rather than a neoplastic
one.
ONCOCYTOSIS (NODULAR ONCOCYTIC HYPERPLASIA)
Clinical Features
Site: parotid gland, in rare instances, it may involve the
submandibular or minor salivary glands.
may be extensive enough to produce clinical swelling.
proliferation is multifocal and nodular, sometimes entire gland can
be replaced by oncocytes- Diffuse hyperplastic oncocytosis.
oncocytosis occurs most frequently in older adults
Histopathologic FeaturesFocal nodular collections of oncocytes with in the salivary gland
tissue
Enlarged cells are polyhedral and demonstrate abundant granular,
eosinophilic cytoplasm as a result of the proliferation of mitochondria
These cells may have a clear cytoplasm from the accumulation of
glycogen
The multifocal nature of the proliferation may be confused with that
of a metastatic tumor, especially when the oncocytes are clear in
appearance.
Oncocytosis. Multifocal collections of clear oncocytes (arrows) in the parotid gland
Treatment and Prognosis
Oncocytosis is a benign condition and often is discovered only as
an incidental finding.
No further treatment is necessary, and the prognosis is excellent.
CANALICULAR ADENOMA
Uncommon tumor
exclusively in the minor salivary glands
Defined as- tumor composed of columnar epithelial cells arranged
in thin, anastomosing cords often with a beaded pattern and a
characteristic paucicellular stroma.- WHO
Clinical Features Age: older people, 7th decade
Sex: F:M- 1.2-1.8:1
Site: upper lip , 75% occurring in this location.
Buccal mucosa is the second most common site. c/p: slowly growing, pain less mass that usually ranges from several
millimeters to 2 cm, firm or somewhat fluctuant to palpation. - The overlying mucosa may be normal in color or bluish and can be
mistaken for a mucocele. - In some instances. the lesion has been noted to be multifocal.
Gross pathology:Varies from discrete encapsulated nodule to lesions that
are circumscribed but encapsulated.Sometimes multifocalPink-tan to tan, brown or yellowSometimes cystic spaces with gelatinous material seen
Histopathologic Features
Monomorphic in nature, single- layered cords of columnar or cuboidal
epithelial cells with deeply basophilic nuclei, adjacent parallel rows of
cells may be seen, resulting in a bilayered appearance of the tumor cords,
showing ‘party wall’.
These cells enclose ductal structures, form of long canals, larger cystic
spaces
Epithelium may demonstrate papillary projections into the cystic lumina.
Tumor cells are supported by a loose connective tissue stroma with
prominent vascularity.
A thin fibrous capsule often surrounds the tumor, although satellite
islands are observed in the surrounding salivary gland tissue .
Differential diagnosis
Basal Cell Adenoma
Pleomorphic adenoma (PA)
Polymorphous low-grade adenocarcinoma (PLGA)
Adenoid cystic carcinoma (AdCC) and
Treatment and Prognosis
local surgical excision.
Recurrence is uncommon and actually may represent cases that are
multifocal in nature.
Cystadenoma “Rare benign epithelial tumour characterized by
predominantly multicystic growth in which the epithelium demonstrates adenomatous proliferation”.
2 morphologic varients- 1) papillary 2) mucinous Papillary cystadenoma- cystic space is filled with papillary
projections Mucinous cystadenoma- mucous cells predominate.
Clinical feature:Age: 8th decadeSex: F:M- 2:1Site: major- parotid minor- lips, buccal mucosa, palate,
tonsillar area. c/p: slow growing, painless slightly
compresssible swelling, nodules are similar to mucocele.
Histologic features:Epithelial proliferations result in various cystic structures.Lining of cyst- varies from flattened to tall columnar cells, and
cuboidal, mucous, and oncocytic cells seen.Lining thickness- 1-3 epithelial cellsLimited papillary growth with central connective tissue core
seen.Eosinophilic or slightly hematoxyphilic secretions are seen in
the stromaDense fibrous connective tissue stroma with scattered
inflammatory cells seen.
Cystadenoma.
Well-circumscribed tumor composed of variably sized, multiple cysts with focal papillary configurations.
The cyst lining epithelium consists of columnar or cuboidal cells.
The cysts contain eosinophilic, proteinaceous material
Treatment:Conservative surgical procedureRecurrence- low
Most common malignant salivary gland neoplasm.
2nd most frequent of occurence of all salivary gland neoplasm
Term was 1st used by Stewart, Foote and Becker in 1945.
5% of all salivary gland neoplasm
MUCOEPIDERMOID CARCINOMA
Etiology:Therapeutic RadiationLipoidal installationPresence of other foreign material
Origin:Cells of the salivary gland excretory and
intercalated duct
Clinical features:
Age: 3rd – 5th decadeSex: females> maleSite: parotid is most commonly affected Intraorally: palateMost common salivary gland neoplasm in children.
c/p: Low grade: slowly enlarging, painless mass, seldom
exceeds 5cm in diameter in low grade. - not completely encapsulated, often contains cysts- filled
with viscoid, mucoid material. - may be mistaken as mucocele. High grade: grows rapidly, facial nerve paralysis -ulceration, trismus, draining from the ear, dysphagia. - metastasis to regional lymph node, lung, bone, brain,
suncutaneous tissue.
Blue-pigmented mass of the posterior lateral hard palate.
Mucoepidermoid carcinoma. Mass of the tongue
Genetics:Infrequent genetic loss at chromosomes 9q21, 8q, 5p, 16
q, 12p.H-ras gene have been shown mutation at codon 12 or 13
Brandwein Mucoepidermoid Carcinoma Criteria
Cut surface of the tumor shows gray white, solid mass accompanied by multiple small cystic structures and infiltrative borders.
Low-grade mucoepidermoid carcinomas may have a distinctly cystic gross appearance.-Cystic spaces- viscid, mucoid material-Areas of hemorrhage seen.
Gross pathology
Histopathological features:Characterized by: variety of cell types and growth
patternsComposed of- a)mucous secreting cells b)epidermoid cells c)intermediate cells d)columnar or clear cellsGrades: a) low grade b) intermediate grade c) high grade
Mucous cells- vary in shape, abundant pale foamy cytoplasm that stains positive for mucin stains.
- relatively large, may assume round, cuboidal, ovoid, columnar or goblet shapes.
- stains positive for mucicarmine and PAS stain.Epidermoid cells- squamous features, polygonal shape.Intermediate cells- larger than basal cell, smaller than
squamous cell. Proginitor of epidermoid and squamous cells.
Clear cells- larger, polygonal and defined cytoplasmic borders.
Histopathological Grades are based on- Amount of cyst formation Degree of cytoplasmic atypia Relative number of mucous, epidermoid & intermediate
cells.
Low grade: Hallmark- prominent cystic structures accompanied by the presence of numerous mature cellular element including mucous cells and extracellular matrix.
- Mucous cell predominate- squamous cell lining the cystic spaces seen.- Size, shape & staining characteristics of cells are
uniform Intermediate grade: intermediate cells predominate
with scattered mucous cells and zones of epidermoid cells forming large, solid islands of tumor.
- Mitotic figures- rare.
Low-grade mucoepidermoid carcinoma: with a prominent cystic component.
Mucus cells - mucicarmine stain,
Clear cells - PAS
Intermediate-grade mucoepidermoid carcinoma with few mucuscells and prominent population of intermediate and epidermoid cells
High grade: nearly solid cellular proliferation of epidermoid & intermediate cells
-Noticiable degree of cellular atypia-N:C ratio altered-nucleoli prominent, mitosis- numerous
2 differentiation pattern:a)Resemble a MDSCCb) variety of cell types that are most often dominated by
intermediate cells.
High-grade mucoepidermoid carcinoma with poorly differentiated,irregular nests of tumor cells and very focal mucinous differentiation.
Mucoepidermoid carcinoma.
Clear cell variant
Oncocytic variant.
Mucoepidermoid carcinoma.
Abundant hyalinized stroma is evident.
Extensive secondary lymphoid cellinfiltration, referred to as tumor-associated lymphoid proliferation.
1)Sclerosing MEC:Extremely rare, characterized by intense central sclerosis
that occupies the entirety of an otherwise typical tumor, frequently with an infiltrate of plasma cells, eosinophils, and/or lymphocytes at its peripheral region.
2 mechanism: Tumor infarction and extravasation of mucins resulting in reactive fibrosis.
varients
2) Intraosseous MEC:Primary intraosseous mucoepidermoid carcinoma (PIOC)
of the jaw bones is an extremely rare malignant salivary gland tumor, comprising 2–3% of all mucoepidermoid carcinomas reported.
commonly seen in the posterior part of the mandibleHistologically low-grade cancersRadiographically seen as uniocular or multiocular
lesions.
Differential diagnosis:Necrotizing sialomataplasiaPleomorphic adenomaInverted ductal papillomaCystadenomaMatastatic SCCSebaceous carcinomaClear cell tumorsAdenosquamous carcinoma
Treatment and prognosis:Conservative excision with preservation of facial nerveSubmandibular gland- removal of the glandMinor salivary gland- surgicalMatastatis- 12% of casesPrognosis- fairly good.
The acinic cell adenocarcinoma is a salivary gland malignancy with cells that show serous acinar differentiation.
Abrams and his coworker, concluded – tumor of this type have atleast a low grade malignant potential.
Defined by cytologic differentiation towards serous acinar cells whose characteristic feature is cytoplasmic PAS positive Zymogen type secretory granules.
17% of primary salivary gland malignancy6% of all salivary gland neoplasm
ACINIC CELL ADENOCARCINOMA
Histogenic theory: By Eversole, later by Regezi and Batsakis,
hypothesizes that ACC develops from stem or reserve epithelial cells located at the tubuloacinar terminal of salivary gland duct unit, i.e, intercalated duct region.
Clinical features:Age: Middle age, 44 yearsSex: female>male (3:2)Site: parotid- 80% Intraorally- lips & buccal mucosac/p: slow growing, mobile or fixed mass of
variable duration.- Asymptomatic usually, pain and tenderness
seen over a third of patient.- Facial muscle weakness can be seen- Bilateral synchronous tumors have been
reported
Acinic cell adenocarcinoma. Small, nodular mass of the hard palate.
Sections through a superficial parotidectomy reveal a sharply demarcated tumor with a partially cystic appearance.
Gross pathology:Primary ACC –mononodular, well circumscribed, 2-4 cm in
diameter
Multinodularity is not infrequent
Color: Grayish white or reddish gray
May be solid or cystic,
Consistency- firm to soft, somewhat friable.
Histopatholgic feature
Highly variable morphologic featureWell circumscribed and encapsulated, may exhibit
infiltrative growth pattern Characteristic cell: serous acinar cells, with abundant
granular basoplilic cytoplasm and round and darkly stained eccentric nucleus.
Mitotic figures- uncommon
Morphologic growth patterns:1. Solid2. Microcystic3. Papillary – cystic4. Follicular
Individual cell can be categorized as:5. Acinar6. Intercalated duct like7. Vacuolated8. Clear9. Nonspecific glandular
Solid growth pattern:Most easily recognisedContain large number of Well Differentiated acinar cells
and most closely resemble normal parotid gland parenchyma.
Composed of sheets of tumor cells that frequently have an organoid configuration.
Groups of tumor acinar cells are separated and surrounded by very thin fibrous septa that contain small, nearly invisible capillaries.
Clear cells often grow
Acinic cell adenocarcinoma. Parotid tumor demonstrating sheet of granular, basophilic serous acinar cells
Acinic cell adenocarcinoma. High-power view of serous cells with basophilic, granular cytoplasm.
Acinic cell carcinoma.
The cells have an abundant cytoplasm filled with basophilic zymogen granules
Acinic cell carcinoma.
Periodic acid Schiff stain highlighting zymogen granules on the luminal aspect
Microcystic pattern:Extensive in 1/3 of ACCNumerous small cystic spaces.Acinar cells still frequent, may be dominating type.Vacuolated and intercalated duct like cells are prominentMucinous material may pool in the cystic space
Papillary- cystic pattern: Cystic structure that contain proliferations of the
epithelium, projecting into lumina. Some epithelial projections have fibrovascular cores, where
as others appear to be masses of epithelium without apparent supporting stroma.
Epithelial proliferations vary in thickness Intercalated duct like and non specific glandular cells
predominate, vacuolated cells also seen. Apical portion of the lumen lining cells bulge into lumen-
produce a hobnail like configuration.
Follicular pattern:Less frequentVariable size- ovoid to round cystic spaces lined by cuboidal to
low columnar epithelial cells.Cystic space- contain proteinaceous material that stimulate the
appearance of colloid Intercystic areas –usually occupied by epithelial cells that are
nonspecific glandular cells with some vacuolated and acinar type cells.
Curious feature- frequent association with a lymphoid infiltrate in the supporting stroma, geminal centres may be evident.
Arise within intraparotid lymph node.
Acinic cell carcinoma with extensive psammoma body formation
Acinic cell carcinoma showing focal clear cell change.
This otherwise typical acinic cell carcinoma shows an area (upper) of higher grade carcinoma with small-cell features.
This phenomenon has been referred to as “dedifferentiation.”
Differential diagnosisNormal salivary glandSialadenitis/ sialadenosisMEC- microcystic typePapillary cystadenocarcinomaClear cell oncocytoma
Treatment and prognosisSurgicalTotal excision with preservation of facial nerve- parotidLymph node dissectionSurgical excision- intraoral tumorsPrognosis- poor
The adenoid cystic carcinoma is one of the more common and best- recognized salivary malignancies.
Slow growing but aggressive neoplasm with a remarkable capacity of recurrence.
Marked propensity for perineural invasion.Adenoid cystic carcinoma is a “basaloid tumour consisting of
epithelial and myoepithelial cells in variable morphologic configurations, including tubular, cribriform, cystic and solid patterns
ADENOID CYSTIC CARCINOMA
Clinical features:Age: 5th- 7th decadeSex: F>MSite: 50-60% within minor salivary gland- palate>
tongue, buccal mucosa.c/p: slowly growing mass. - Pain is a common and important finding- Patients often complain of a constant , low-grade, dull
ache, which gradually increases in intensity. - Facial nerve paralysis may develop with parotid
tumors.- Palatal tumors can be smooth surfaced or ulcerated. - Tumors arising in the palate or maxillary sinus may
show radiographic evidence of bone destruction
Adenoid cystic carcinoma. Painful mass of the hard palate and maxillary alveolar ridge.
Adenoid cystic carcinoma of the parotid gland has deceptively well-delineated outlines. Microscopically, the tumor extends well beyond the grossly apparent edges of the tumor.
White or grayish white color, firm, invasive tumor.Areas of hemorrhage seen.
Gross pathology
Histopathologic features:The adenoid cystic carcinoma is composed of a mixture
of myoepithelial cells and ductal cells that can have a varied arrangement.
Three major patterns are recognized; (1) cribriform , (2) tubular, and (3) solid.Usually a combination at these is seen, and the tumor is
classified based on the predominant pattern.
Cribriform pattern:The cribriform pattern is the most classic and best recognized
appearance, characterized by islands of basalaid epithelial cells that contain multiple cylindrical, cyst like spaces resembling Swiss cheese or honeycomb pattern.
These spaces often contain a mildly basophilic mucoid material a hyalinized eosinophilic product , or a combined mucoid hyalinized appearance.
Sometimes the hyalinized material also surrounds these cribriform islands.
Tubular pattern:Tubular structure that are lined by stratified cuboidal
epithelium.Longitudinal section- ductal structures are viewed as ducts or
tubules.Lumina contains mucinous substance- PAS positiveCribriform pattern may exist with tubular pattern.
Adenoid cystic carcinoma.
Tubular variant showing morphologically clear abluminal cells.
Solid pattern:Solid groups of cuboidal cells with little
tendency towards ducts or cyst formation.Arranged in nests or sheets of varying size
and shape.Areas of necrosis seenCellular pleomorphism, mitosis observed.
Adenoid cystic carcinoma.
Solid variant higher power showing scattered duct-like structures within the tumor sheet.
Adenoid cystic carcinoma. The tumor cells aresurrounded by hyalinized material
Adenoid cystic carcinoma. Perineural invasion.
Dedifferentiation of adenoid cystic carcinoma- Recently defined, rare varient.- characterized histologically by 2 component1. Conventional low grade adenoid cystic carcinoma2. high grade dedifferentiated carcinoma. Because of frequent recurrence and matastasis, the
clinical course is short, similar to AdCC with a predominant solid growth pattern.
Histologically low grade AdCC merges gradually into extensive dedifferentiated component that is composed of solid sheets and cords of anaplastic tumor cell with focal gland formation..
p53 gene alteration plays a pivotal role.
Varients
Differential diagnosis:Basal cell adenomaPolymorphous low grade adenocarcinomaBasaloid squamous carcinomaBasal cell adenocarcinoma
Treatment and PrognosisSurgical excisionAdjunct radiation therapy may slightly
improve patient survival in some cases.Prognosis- poor
Epithelial myoepithelial carcinoma (EMEC) is a rare low-grade malignant salivary gland neoplasm.
less than 1% of all salivary gland neoplasms.ORIGIN: intercalated ductA malignant tumor composed of variable proportions of two
cell types, which typically form duct-like structures.The biphasic morphology is represented by an- Inner layer of darker cells, that represent intercalated duct
epithelial component- Outer layer of clear, myoepithelial-type cells.
EPITHELIAL MYOEPITHELIAL CARCINOMA
Clinical feature:
Age: older, 6th- 7th decade of life.Sex: F>MSite: parotid- 75%> submandibular gland intraorally: palate, tongue.c/p: Asymptomatic, or painful salivary gland swelling with
a history of steady increase in size over an extended period of time.
Facial paralysis & Localized swellings Locally infiltrative, destructive growth pattern & frequent
rate of recurrence. Facial deformity & nasal obstruction- incase of maxillary
involvement Increased risk of secondary primary tumor- either in
salivary gland or in separate site
Extra oral swelling on the left side of face
Gross pathology:Single, well circumscribed, firm, lobulated neoplasm that
ranges from 2-8 cmOn cross section- multinodular growth pattern with
irregular cystic spaces.Recurrent tumors- multicentric growth with irregular
tumor borders and central areas of necrosis.
Histopathological features:
Multinodular growth pattern with islands of tumor cells
separated by dense band of fibrous connective tissue.
Islands of tumor cells composed of small ducts lined by
cuboidal epithelium that is surrounded by clear cells that
interface with thickened hyaline like basement membrane.
Inner- luminal cuboidal cells have finely granular, dense, eosinophilic cytoplasm and central or basally located round nuclei.
- Columnar cells and squamous foci may also be seen proliferating within cystic and microcystic space that often contain material that reacts positivity to PAS stain.
Outer- clear myoepithelial cell vary in shape from columnar to ovoid, well defined cell borders, eccentrically located vesicular nuclei located towards the basement membrane.
- Clear myoepithelial predominates mitotic figures- rareVascular invasion & neurotropism may be seen.
Higher magnification showing luminal intercalated Duct like cells and abluminal clear cells.
Another area Showing luminal cuboidal cells and abluminal clear cells and dense hyalinised basement membrane (Original magnification,)
Epithelial-myoepithelial carcinoma with trabecular arrangement & predominantly non-canalized ducts.
Epithelial-myoepithelial carcinoma.
Not uncommonly some glandular structures have dilated lumens or are thrown into papillary folds. This feature is practically never seen in adenoid cystic carcinoma.
S – 100 immunohistochemistry
p63 immunohistochemistry
Differential diagnosis:Pleomorphic adenomaClear cell tumorsClear cell oncocytomaMyoepithelial carcinomaClear cell myoepitheliomaMucoepidermoid carcinomaMalanoma Adenoid cystic carcinoma
Treatment
Wide surgical excisionRecurrence rate- 30-50%
Recently recognized type of salivary malignancy that was first
described in 1983.
Evans and Batsakis first used the term
PLGA occurs almost exclusively in the minor salivary glands
Characterized by: Bland, uniform nuclear feature, diverse by
characteristic architecture, infiltrative growth and perineural
invasion.
POLYMORPHOUS LOW-GRADE ADENOCARCINOMA (LOBULAR CARCINOMA; TERMINAL DUCT CARCINOMA)
Clinical features:Age: 50-80 yearsSex- F:M=2:1Site: 50-60%- palate, 16%- buccal mucosa, 12%-
upper lip, major SG- parotidc/p- Most often appears as a pain less mass that
may have been present for a long time with slow growth.
- Associated with bleeding, discomfort, telangiectasia, ulceration.
- Tumor can erode or infiltrate the underlying bone.
Polymorphous low-grade adenocarcinoma. Ulcerated mass of the posterior lateral hard palate
Gross pathology:Firm, circumscribed, but non-encapsulated, yellow tan
lobulated nodule, average size 2.2cms.Bony invasion may be seem in large lesion in the hard patate,
may impinge upon the maxillary bone and cause bone resorption and laterally medullary invasion
Gross image shows bone invasion in a large tumor in the hard palate
Histopathologic features:
Characterized by: Infiltrative growth with diverse morphology
& Uniform nuclear appearance
At low power, the tumor sometimes appears well circumscribed.
peripheral cells are usually infiltrative, invading the adjacent
tissue in a single- file fashion.
Difference growth pattern- hence the name polymorphous.
Variety of growth patterns- solid, ductal, cystic, tubular or
cribriform
Tumor stroma- varies from mucid to hyaline and in some areas
separated by fibrovascular stroma.
In some tumors, a cribriform pattern can be produced that
mimics adenoid cystic carcinoma .
Mitotic figures are uncommon.
Perineural invasion common.
Histopathological image shows uniform nuclei, round to ovoid, with ground-glass type nuclear chromatin
Histopathological image shows whorling around small neurovascular bundles; a targetoid appearance
Polymorphous low-grade adenocarcinoma . Thismedium-power view shows a cribriform arrangement of uniformtumor cells with pale-staining nuclei
Polymorphous low-grade adenocarcinoma.Pale-staining cells which infiltrate as single-file cords.
Tubular structures are predominantly lined by a single layer of small cuboidal cells.
Multiple pseudocystic spaces with pale staining amphophilic mucoid contents resulting in a cribriform appearance
Differential diagnosis:Pleomorphic adenomaAdenoid cystic carcinoma
Treatment and PrognosisThe polymorphous low-grade adenocarcinoma is best
treated by wide surgical excision, sometimes including resection of the under lying bone.
Metastasis to regional lymph nodes is relatively uncommon, occurring in just under 10% of patients.
Therefore, radical neck dissection seems unwantedDistant metastasis is rare.
Surgical pahology of the salivary glands, Gary L Ellis, Paul L Auclair.
Shafer’s textbook of oral pathology, 6th edition.
Oral and maxillofacial pathology, 3rd edition, Neville.
Color/Atlas text of salivary gland tumor pathology, Irving Dardick.
Gnepp, diagnostic surgical pathology of the head and neck
References
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