Biopsypathologyof acquired immune deficiency syndrome(AIDS)

J Clin Pathol 1987;40:1-8

Biopsy pathology of acquired immune deficiencysyndrome (AIDS)A W BOYLSTON,* H T COOK, N D FRANCIS, R D GOLDIN

From the Department of Pathology, St Mary's Hospital Medical School, London

SUMMARY Between January 1982 and May 1986 279 biopsy specimens from 82 patients withacquired immune deficiency syndrome (AIDS) were examined. A wide variety of infectious condi-tions were diagnosed, the commonest being Pneumocystis pneumonia (n = 36), cytomegalovirus(n = 21), a variety of fungi (n = 8), mycobacteria (n = 7). Kaposi's sarcoma was the commonesttumour (n = 40), and there were two cases of extranodal lymphoma.

Striking features were the unusual sites of disease and the occasional paucity of organisms.

The acquired immune deficiency syndrome (AIDS) isone of the manifestations of infection with a humanretrovirus that has been given at least four names. Itis known variously as lymphadenopathy associatedvirus (LAV), human T lymphocytotrophic virus typeIII (HTLV III), AIDS related virus (ARV), or humanimmunodeficiency virus (HIV).' 2 As defined by theCentre for Disease Control (CDC) in Atlanta,Geogia, the syndrome is the appearance of Kaposi'ssarcoma or opportunistic infection in the presence ofserological evidence of infection by the causativevirus.34 It has long been apparent that AIDS is notsynonymous with HIV infection and that manypatients infected by this virus are healthy or have lessdevastating symptoms, such as persistent generalisedlymphadenopathy, which are sometimes lumpedtogether as the "AIDS related complex" or "minorAIDS".5

This paper describes the biopsy pathology of agroup of 100 consecutive patients with AIDS seen inone hospital between 1982 and mid 1986. Onlypatients who fulfilled the CDC criteria for the fulldiagnosis of AIDS were included. The study coversabout 30% of the registered patients with AIDS in theUnited Kingdom during the study period.At present AIDS is largely confined to subjects in

certain clearly defined risk groups, particularly malehomosexuals, haemophiliacs, and users of intra-venous drugs.3 Outside western Europe and NorthAmerica, however, the syndrome is common in bothsexes, and evidence of probable heterosexual trans-mission is abundant.67 This means that AIDS mayoccur in migrants or visitors from areas with adifferent distribution of the disease. It may eventually

Accepted for publication 16 September 1986

spread into the general population of the UnitedKingdom as well. Thus all surgical pathologists mayeventually have to deal with biopsy specimens fromthose with AIDS, and in at least some instances thediagnosis may not have been suspected on clinicalgrounds. While most of the diagnoses that were madein our patients are familiar to pathologists in centreswith transplantation units or haematological oncol-ogy departments, they are not common outside thesespecialised centres.The purpose of this report is to outline the spec-

trum of unusual diagnoses encountered and to indi-cate that in many instances the appearances differfrom those found in classical reference works.

Material and methods

One hundred patients with AIDS were seen in thishospital during the interval 1982 to mid May 1986. Ofthese, 82 had at least one tissue biopsy. The 19patients who did not have biopsies were diagnosed ashaving AIDS on the basis of characteristic clinical orradiological signs of processes such as cerebral toxo-plasma abscess (n = 2) or cytomegalovirus (CMV)retinopathy (n = 2) or both. In addition, 11 patientswith oral or oesophageal candidiasis did not have abiopsy. Three patients had Pneumocystis carinii pneu-monia and one patient had cryptosporidium infec-tion, which had been diagnosed at another hospital;the biopsy material was not available for review. Atotal of 279 biopsy specimens were available for thisstudy. All the specimens from all the patients wereincluded in this study.

Specimens from patients suspected of having AIDSwere received in appropriately packaged 10% formolsaline, with a biohazard warning label. They were

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fixed for a minimum of 12 hours, except for urgentbronchial biopsy specimens, which were fixed for onehour at 37°C. They were processed and embedded bystandard methods, cut, and stained as describedbelow.LUNGThese were sectioned at a minimum of three levelsand stained with haematoxylin and eosin, periodicacid Schiff, Ziehl-Neelsen and Grocott's methena-mine silver. The urgent bronchial biopsy specimenswere rapidly processed so that three levels stainedwith Grocott's methenamine silver were available forexamination within five hours of receiving the biopsy.GUTThese were sectioned at a minimum of three levelsand stained with haematoxylin and eosin, periodicacid Schiff, Ziehl-Neelsen and May-Grunwald-Giemsa.

SKINThese were sectioned at a minimum of three levelsand stained with haematoxylin and eosin, periodicacid Schiff, Ziehl-Neelsen and Grocott'smethenamine silver.LIVERThese were serially sectioned and stained with hae-matoxylin and eosin, periodic acid Schiff withdiastase, silver impregnation for reticulin, iron vanGieson, Ziehl-Neelsen, Masson's trichrome, andGomori's aldehyde fuchsin.

LYMPH NODESThese were serially sectioned and stained with hae-matoxylin and eosin, periodic acid Schiff, reticulin,May-Grunwald-Giemsa and methyl green pyronin.OTHER SPECIMENSThese were initially stained with haematoxylin andeosin and other stains, as indicated.

ResultsAll but one of the patients were male and their agesranged from 19 to 54 years at the time of diagnosis.Table 1 lists all the sites from which the biopsy speci-mens were obtained. In tables 2-6 these are furtheranalysed by site and diagnosis. Figs 1 to 7 show thehistological findings in different infections.Table 1 Sites ofbiopsies obtainedfrom patients with AIDS

Site No ofpatients No ofbiopsies

All 82 279Skin 35 55Respiratory tract 56 92Gastrointestinal tract 46 84Liver 16 21Lymphoreticular 18 23Other 4 4

Boylston, Cook, Francis, Goldin

Table 2 Skin biopsy diagnoses in patients with AIDS

Diagnoses No ofpatients No of biopsies

Kaposi's sarcoma 25 33Fungi* 4 4Vasculitis 10 I1Other 5 8t

*Cryptococcus neoformans (figs 5a and Sb) and histoplasmacapsulatum (figs 6a and 6b). In two cases the type of fungus couldnot be identified.tOne molluscum contagiosum, one dermatofibroma, one naevus,one milia, two acne, and two abscesses.

Table 3 Diagnoses on respiratory tract biopsy specimens inpatients with AIDS

Diagnoses No ofpatients No of biopsies

Pneumocystis carinii 28 36Fungi 2 2Cytomegalovirus 4 5Mycobacteria 4 4Acute bacterialpneumonia 3 3

Non-specific 22 40Other 5 6*

*One each of acute bronchitis, Kaposi's sarcoma, laryngeal dys-plasia, nasal papilloma, and two of malaria.

Table 4 Gastrointestinal tract biopsy specimensfrompatients with AIDS

Diagnoses No ofpatients No of biopsies

Mouth and pharynx:Kaposi's sarcoma 2 2Lymphoma 1 INon-specific 2 4

Oesophagus and stomach:Cytomegalovirus 2 3Kaposi's sarcoma I ICandida I INon-specific 2 4

Small bowel:Cryptosporidium I IMycobacterium 1 INormal 2 2

Colon, rectum, and anus:Cytomegalovirus* 8 13Herpes* 2 2Mycobacteriwn I IOedema or ulceration,

or both 30 48Kaposi's sarcoma 1 2Lymphoma I IAbscess I I

*Illustrated in fig 7a.

Biopsy pathology ofAIDS

Table 5 Liver biopsy specimensfrom patients with AIDS

Diagnoses No ofpatients No of biopsies

Acute viral hepatitis 5 5Non-specific hepatitis 3 3Cytomegalovirus 3 4Granulomas 1 2Mycobacteriwn 1 1Cirrhosis 1 1Fatty infiltration 2 2Malaria 1 1Histoplasma 1 1Peliosis 1 2Normal 1 I

3Table 6 Biopsy diagnoses oflymphoreticular system inpatients with AIDS

Diagnoses No ofpatients No of biopsies

Lymph nodes:Follicular hyperplasia 6 6Lymphocyte depleted 4 4Castleman's disease 1 IKaposi's sarcoma I IMycobacteria 1 1

Bone marrow:Normal 6 6Non-specific 4 4

Discussion Kaposi's sarcoma in patients with AIDS hascharacteristic appearances that have been well

In our series 82% of patients had at least one tissue described.8 9 While necropsy studies suggest thatbiopsy, and the average number of biopsies was 3.4 widespread dissemination of Kaposi's sarcoma isper patient. A wide range of variation was disguised common,10 systemic disease was found in biopsyby these figures; one patient had had 13 biopsies dur- specimens from only four of 28 patients, and in theseing a long and complex course. patients previous skin biopsies showing Kaposi's sar-

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Biopsy pathology ofAIDS

Fig 4a Lung biopsy specimens showing amorphous granular periodic acid Schiffpositive material in alveolar spaces.x 250.Fig 4b Cysts ofPneumocystis carinii in alveolar exudate shown in fig4a. (Grocott.) x 1000.X tv -* Kx . pFig 5a Skin biopsy specimen showing both granulomatous and mucoid types ofcryptococcal infection (Haematoxylinand eosin.) x 250.Fig 5b Cryptococcal organisms shown in mucoid areas offig Sa. (Grocott.) x 400.

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6

coma had been obtained. Thus presentation of AIDSas the unexpected finding of Kaposi's sarcoma in anorgan other than the skin was rare.

Fourteen different micro-organisms were identifiedin biopsy material. The presence of more than oneorganism in a biopsy specimen was not uncommon,and in one specimen four separate infections wereidentified. Table 7 summarises the range of multipleinfections in single biopsy specimens. Because of theTable 7 Multiple infectious agents seen in tissue biopsies

Site Organisms identified

Lung Pneumocystis carinii pneumonia, CMVAnal skin Herpes, CMVLung Pneumocystis carinii pneumonia, CryptococcusLung Pneumocystis carinii pneumonia, CMVLung Pneumocystis carinii pneumonia, AFB, CMV,

malariaLung Pneumocystis carinii pneumonia, CMVLung Pneumocystis carinii pneumonia, AFBLung Pneumocystis carinii pneumonia, acute

pneumonia with Gram positive diplococci

Boylston, Cook, Francis, Goldindiverse infections encountered, we evolved a protocolfor the stains routinely used on biopsy specimensfrom various sites.

In patients with AIDS some of the infections haveappearences different from those commonly encoun-tered. This is particularly true of mycobacteria andcytomegalovirus (CMV). In most of our biopsy speci-mens in which mycobacteria were identified theorganisms were present in large numbers inside mac-rophages. The appearances varied from a singlemycobacteria stuffed cell in the lamina propria of alarge bowel biopsy specimen, which mimicked amuciphage in the periodic acid Schiff stain (figs I a andb) to a solid sheet of bacteria filled cells replacing anabdominal lymph node (figs 2a and b). ` These speci-mens resembled the appearances seen in lepromatousleprosy. Caseating granulomas were not found in ourpatients, probably reflecting their immunodeficiency(figs 3a and b).

Cytomegalovirus infection was most commonlyidentified by the presence of a single cell containing

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Fig 6a Skin biopsy specimen showing cutaneous inflammatory infiltrate in disseminated histoplasmosis, (Haematoxylinand eosin,) x 40.Fig 6b Histoplasma organisms intracellular and extracellularfrom lesion shown infig 6a. (Periodic acid Schiff.) x 1000.

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Biopsy pathology of AIDS

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Fig 7a Ulceratedperianal skin and underlying inflammatory infiltrate. (Haematoxylin and eosin.) x 125.Fig 7b Multinucleated squamous cells characteristic ofherpes infectionfrom ulcerated lesion infig 7a. (Haematoxylinand eosin.) x 400.Fig 7c Mononuclear cell containing intranuclear inclusion body characteristic ofCMV in inflammatory infiltrate shown infig 7a. (Haematoxylin and eosin.) x 530.

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8 Boylston, Cook, Francis, Goldinthe characteristic intranuclear inclusion. This cell wasusually not related to small blood vessel endothelium,as commonly described, but occurred anywhere.'2In particular, cells with the appearances of luminalepithelium or lying free in the lamina propria of thegastrointestinal tract mucosa were found. Cellsresembling either monocytes or desquamatedpneumocytes containing inclusions were seen in lungbiopsy specimens. We did not observe evidence ofCMV infection in lesions of Kaposi's sarcoma.

Pneumocystis carinii pneumonia also showed bothtypical and atypical features.'3 Characteristically thealveoli contained foamy eosinophilic material, whichwas strongly periodic acid Schiff positive (fig4a). Inmost cases large clusters of cysts, appearing as roundor oval concave discs with refractile margins, wereseen in the Grocott's methenamine silver stained sec-tions (fig 4b). They were similar in size to red cells andin overstained sections may be difficult to distinguish.The use of a control positive section stained in paral-lel with the biopsy specimen was a very usefulapproach to the successful diagnosis. In many suchspecimens, however, cysts were sparse and could beseen in only one of multiple levels. The absence oftypical clusters of cysts did not exclude the diagnosisof Pneumocystis carinii pneumonia.The large numbers of rectal biopsies performed on

this group of patients reflected the incidence of diar-rhoea. The cause of this symptom is often obscure.3The commonest specific organisms that have beenidentified are CMV and mycobacteria. A large pro-portion of the biopsy specimens did not yield aspecific agent; only 16 of the 68 large bowel and analspecimens showed an organism. None of the rectalbiopsy specimens, however, was completely normal.The changes observed ranged from mild oedemaassociated with a slight increase in chronicinflammatory cells and lymphoid follicle involution tointense oedema, superficial ulceration, and an appar-ent decrease in cells in the lamina propria. Occasionalnecrotic glands and crypt abscesses were also noted.An interesting observation was that none of thesespecimens showed evidence of spirochaetosis.The changes observed in the small number of

lymph nodes examined were similar to those seen inother studies.`4 The appearances ranged from fol-licular hyperplasia through follicular involution tolymphocyte depletion. Although it has been suggestedthat these changes can be used to generate a three tierstaging scheme for AIDS lymphadenopathy, ourexperience is that the changes overlap and one nodemay show areas of both follicular hyperplasia andinvolution. It is worth emphasising that there are nospecific diagnostic features of AIDS in lymph nodes,apart from Kaposi's sarcoma or an opportunisticorganism.There were two lymphomas, and both were diffuse

high grade large cell lymphomas showing plas-macytoid differentiation arising in extranodal sites.Similar tumours have been observed by others inpatients with AIDS.`5 The atypical presentation ofthese tumours, one as an ulcerating lesion on theneck, and the other as an anal fistula, should beemphasised.Our experience of the biopsy pathology of patients

with AIDS closely resembles that reported fromNorth America. 16 All biopsy specimens from patientswith suspected AIDS should be examined at multiplelevels and routine special stains used. This will pickup small numbers of organisms that may occur inunexpected sites and may produce atypical histologi-cal and clinical pictures. The possibility of multipleinfections in one patient or a single biopsy specimenshould always be considered.References

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2 Marx JL. "AIDS virus has new name-perhaps. [Editorial]. Sci-ence 1986;232:699-700.

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4 Centre for Disease Control. Update on acquired immunedeficiency syndrome. MMWR 1982;31:507-8.

5 Marthur-Wagh V, Enlow RW, Spigland Z, et al. Longitudinalstudy of persistent generalized lymphadenopathy in homo-sexual men: relation to acquired immune deficiency syndrome.Lancet 1984;i:1033-8.

6 Harris C, Small CB, Klein RS, et al. Immunodeficiency in sexualpartners of men with the acquired immune deficiency syn-drome. New Engi J Med 1983;308:1 181-4.

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8 Francis N, Parkin J, Weber J, Boylston A. Kaposi's sarcoma inacquired immune deficiency syndrome (AIDS). J Clin Pathol1986;39:469-74.

9 Gottleib GJ, Ackerman AB. Kaposi's sarcoma: an extensivelydisseminated form in young homosexual men. Hum Pathol1982;13:882-92.

10 Niedt GW, Schinella RA. Acquired immune deficiency syn-drome. Arch Pathol Lab Med 1985;109:727-34.

11 Gillin JS, Urmacher C, West R, Shike M. DisseminatedMycobacterium avium-intracellulare infection in the acquiredimmune deficiency syndrome mimicking Whipples disease.Gastroenterology 1983;8S: 1187-91.

12 Meiselman MS, Cello JP, Margaretten W. Cytomegalovirus col-itis. Report of the clinical, endoscopic and pathological findingsin two patients with the acquired immune deficiency syndrome.Gastroenterology 1985;88: 171-5.

13 Marchevsky A, Rosen MJ, Chrystal G, Kleinerman J. Pulmonarycomplications of the acquired immune deficiency syndrome.Hum Pathol 1985;16:659-70.

14 Ewing EP, Chandler FW, Spira TJ, Brynes RK, Chan WC. Pri-mary lymph node pathology in AIDS and AIDS relatedLymphadenopathy. Arch Pathol Lab Med 1985;109:977-81.

15 Ioachim HL, Cooper MC, Hellman GC. Lymphomas in men athigh risk for AIDS. Cancer 1985;56:2831-42.

16 Amberson JB, DiCarlo EF, Metroka CE, Koizumi JH, Mou-radian JA. Diagnostic pathology in the acquired immuno-deficiency syndrome. Arch Pathol Lab Med 1985;109:345-51.

Requests for reprints to: Dr AW Boylston, Department ofPathology, St Mary's Hospital Medical School, LondonW12, England.