84 Clin Pathol 1996;49:844-847

Aluminium and injection site reactions

G A Culora, A D Ramsay, JM Theaker

AbstractAims-To alert pathologists to the spec-trum ofhistological appearances that maybe seen in injection site reactions relatedto aluminium.Methods-Four cases of injection sitereaction were examined microscopicallyusing routine staining with haematoxylinand eosin, electron microscopy and byelectron probe microanalysis.Results-As in previous reports, all fourcases included collections of histiocyteswhich contained faint granular brownishrefractile material within their cytoplasm;ultrastructural examination showed thisto be aluminium. Two cases showed aprominent inflammatory reaction withnumerous lymphoid follicles and a notableeosinophilic infiltrate. Two cases showedunusual features not described previously.In one, there was a sclerosing lipo-granuloma-like reaction with unlinedcystic spaces containing crystalline mate-rial. The other case presented as a largesymptomatic subcutaneous swelling whichmicroscopically showed diffuse and wide-spread involvement of the subcutis by alymphoid infiltrate with prominent lym-phoid follicles.Conclusions-This report highlights thechanges encountered in aluminium injec-tion site reactions and emphasises that thelesions have a wider range of histologicalappearances than described previously.(7 Clin Pathol 1996;49:844-847)

Keywords: aluminium, injection site, skin.

after injection of aluminium adsorbedvaccines"-" Most of the reported cases haveoccurred in children under three years of age,but reactions have been seen in adults up to 51years old.'2

Histologically, the classic appearance ofthese injection site reactions consists of anodular inflammatory infiltrate with lymphoidfollicles within the deep dermis and subcutane-ous tissue.' 1" Large collections of macro-phages are seen and an eosinophil polymorphinfiltrate is usual. In some cases scattered giantcells and areas of eosinophilic necrosis arepresent. Finely granular refractile material canusually be found within macrophages and thediagnosis can be confirmed using electronprobe microanalysis.We searched our files over the past five years

for patients who developed subcutaneous nod-ules following vaccination and describe a vari-ety of histological appearances, two of whichare outside the range of patterns describedpreviously. In addition, one case had anunusual clinical presentation and course.

Case historiesCASE 1A two year old boy developed a tender subcu-taneous lump on the right buttock, which hadincreased in size over six months and measured10 mm in diameter at excision. He hadreceived diphtheria, tetanus and pertussis vac-cination at this site when he was one year old.This lesion was excised and did not recur.

As a result of its ability to heighten the immuneresponse,' aluminium hydroxide is used as anadjuvant in a wide range of vaccines, includingthose for diphtheria, tetanus, pertussis, hepati-tis A, and hepatitis B. However, hypersensitiv-ity reactions to aluminium compounds are wellknown and include allergic contact sensitivitydeveloping after desensitisation of hay feverwith aluminium precipitated allergens,2 reac-tions to antiperspirant sticks,3 and reactions tothe empty Finn chamber aluminium discs usedfor patch testing of potential allergens. Factoryworkers using recycled aluminium have devel-oped a pruritic dermatitis from dust composedof a mixture of aluminium and possibly othermetals4 and eczematous lesions have developedin aircraft workers exposed to aluminiumfilings.5 Transient inflammatory reactionscausing little discomfort but lasting for up to afew weeks occasionally complicate vaccina-tion26 and, rarely, painful subcutaneous nod-ules develop at vaccination sites up to two years

CASE 2A 48 year old woman developed a diffuse 70mm diameter subcutaneous swelling over theleft deltoid and upper arm, which was itchyand tender. The patient believed this to berelated to an insect bite and the initialhistopathological opinion supported this. Shewas treated with topical steroids, antifungalagents and antibiotics but with no improve-ment. The correct nature of the reactionbecame apparent at a clinicopathological re-view meeting some months later. She hadreceived tetanus vaccination at that site threemonths prior to the development of symptomsand she was subsequently shown to have apositive reaction to empty aluminium Finnchambers used for patch testing. She under-went a total of three excisions over a two yearperiod in an attempt to alleviate symptoms.Although there is no current visible swelling orinduration the patient still complains of itchingalong and around the scar.

Department ofHistopathology,SouthamptonUniversity Hospitals,Tremona Road,Southampton,Hampshire S016 6YD

Correspondence to:Dr J M Theaker.

Accepted for publication27 June 1996

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Aluminium and injection site reactions

Figure 1 Macrophages containing cytoplasmic refractile granular material.

Figure 2 Case 2. Lymphoidfollicles, sheets of macrophages and occasionalfibrous tissuestrands can be seen diffusely extendinzg through the subcutaneous fat.

CASE 3

A three year old boy developed a tender subcu-taneous lump in the left thigh which had beenenlarging over the previous six months. He hadreceived diphtheria, tetanus and pertussis vac-

cination at this site one year previously. Onexcision, the mass was a firm 10 mm nodulecontaining cystic spaces. There was no recur-rence after excision.

CASE 4

A 26 year old woman presented with a painfulsubcutaneous nodule on the right upper armwhich had developed gradually over six monthsfollowing tetanus vaccination. There was norecurrence after excision.

MethodsTissue from all patients was examined micro-scopically after rountine staining with haema-toxylin and eosin, by electron microscopy andby electron probe microanalysis. Tissue sub-mitted for the latter was sent as 1 mm thick

slices fixed in 3% cacodylate buffered glutaral-deyde. Each slice was treated further with 2%cacodylate buffered osmium tetroxide and theblock stained with 2% aqueous uranyl acetate.Tissue slices were then embedded in Spurr'sepoxy resin.

Semi-thin 0.5 gm sections were cut andstained with toluidine blue for light micros-copy, from which suitable areas for thepreparation of ultra-thin 100 nanometre sec-tions were selected. These sections weremounted on formuar coated grids. Tissue wasthen examined by transmission electron micro-scopy and an x ray spectrum was acquired overa period of 100 seconds at 60 KV using aHitachi H7000 electron microscope equippedwith a link PXA1 x ray analysis system.

ResultsLIGHT MICROSCOPYCase 1This lesion consisted of a fibrous nodule withinwhich were lymphoid follicles and sheets ofmacrophages containing granular slightly re-fractile brownish material (fig 1). Numerouseosinophils were seen. There was no evidenceof necrosis and giant cells were not present.The vessels around the edge of the lesionshowed a perivascular lymphocytic infiltrate.

Case 2This case showed a more diffuse histologicalpicture extending into subcutaneous fat. Theinfiltrate consisted of lymphoid follicles andsheets of histiocytes, some containing faintgranular material. An abundance of eosi-nophils was present, but only occasionalstrands of fibrous tissue extended through thelesion (fig 2). A subsequent biopsy specimentaken from the edge of the lesion showed onlya perivascular lymphocytic and eosinophilicinfiltrate. The most recent excision biopsyspecimen showed similar features to the firstone.

Case 3In this case, the subcutaneous fat contained awell circumscribed inflammatory mass with asclerosing lipogranuloma-like appearance withsurrounding fibrosis (figs 3 and 4). Theinflammatory infiltrate consisted of lym-phocytes and histiocytes containing granularmaterial, shown to be aluminium on electronprobe microanalysis. In addition, occasionalcrystalline deposits were seen within the wallsof pseudocystic spaces with an associatedforeign body giant cell reaction. These crystalsdid not stain with solochrome-azurin (foraluminium). Foci of dystrophic calcificationwere also present. Neither lymphoid folliclesnor an eosinophil infiltrate was present in thiscase.

Case 4This specimen consisted of subcutaneous fatcontaining a nodular collection of chronicinflammatory cells and sheets of histiocyteswith faint granular cytoplasmic material. Verylittle fibrous tissue was present within or

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Figure 3 Case 3. A well circumscribed nodule of inflammatory tissue with associatedfibrosis. Occasional deposits of crystalline substance within the lumen and walls of cysticspaces can be seen.

Figure 4 Case 3. Sclerosing lipogranuloma-like areas are present.

Figure 5 Macrophage containing granular aluminium deposits (original magnificationx8000).

around the lesion. There were no giant cells,lymphoid follicles nor an eosinophil infiltrate.

ELECTRON MICROSCOPY AND ELECTRON PROBEMICROANALYSISAll four cases showed characteristic granularelectron dense deposits within histiocytes (fig5), and these were confirmed as aluminium onelectron probe microanalysis.The crystalline deposits in the third case dis-

solved on tissue processing for electron micros-copy and it was not possible to assess theirnature by electron probe microanalysis.

DiscussionThe clinical site and the knowledge of a recentvaccination may alert the clinician to thecorrect diagnosis of an injection site reaction toaluminium. However, if the reaction developssome time after the vaccination, then thepatient and the clinician may attribute thelesion to another cause. To make a correctdiagnosis, the histopathologist should be awareof the range of appearances of this condition,otherwise the histological picture may be easilymistaken for those of a non-specific inflamma-tory reaction, infection or an insect bite. Mostcases present as a tender or itchy subcutaneousnodule which may be gradually enlarging;eczema and hypertrichosis may be noted in theskin overlying the lesions.'" 13 The single mostimportant diagnostic histological feature is thepresence of collections of histiocytes contain-ing faint granular brownish refractile material,which can be shown to be aluminium by elec-tron probe microanalysis. Previous studieshave highlighted two common histological pat-terns seen in addition to the histiocyte sheets inbiopsy specimens." There may be a necrotisinggranulomatous reaction with associated fibro-sis and chronic inflammation or a mixedinflammatory reaction with fibrosis and ahistiocytic or lymphocytic proliferation. Aneosinophil polymorph infiltrate is also com-monly present.Our cases show a wider variation in appear-

ances than other reports, with two of the casesshowing features not described previously.

In one (case 3) there was a sclerosinglipogranuloma-like reaction with pseudocysticspaces within dense fibrous tissue, somecontaining crystalline aggregates with an asso-ciated foreign body giant cell reaction. At-tempts at identifying the nature of thissubstance failed, but they may have repre-sented deposits of crystallised vaccinationmaterial. What induced this lipogranuloma-tous reaction is unclear. We are not aware of an'oily' base in current vaccines used routinely,and this has been confirmed on personalenquiry to the manufacturers.

Case 2 was unusual both clinically andhistologically. Not only was the lesion consid-erably larger and more diffuse than in previ-ously described cases but the patient sufferedsevere symptoms. Histologically, the lesioninvolved the subcutaneous fat and consistedpredominantly of lymphoid follicles and thecharacteristic histiocyte sheets with a promi-nent eosinophil infiltrate. Attempts to excise

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the area completely for symptom relief havenot been fully successful. The patient remainssymptomatic and the histological inflamma-tory changes have extended to the margins ofthe final wide excision. Injection site reactionstypically present as a relatively localised mass,whereas this patient had very widespread anddiffuse changes, far outside the area of vaccina-tion. The patient was sensitive to aluminiumon patch testing, and her severe symptoms anddiffuse and widespread inflammatory responsepresumably relate to this.The combination of a prominent eosinophil

infiltrate in the background of lymphoidfollicles has provoked some discussion aboutthe relation between such reactions andangiolymphoid hyperplasia with eosinophilia.Occasional irregularly shaped capillaries withconspicuous endothelial cells were present inour cases, but they were not a prominentfeature. Although the aetiology and pathogen-esis of angiolymphoid hyperplasia are notknown, it typically presents as multiple cutane-ous nodules on the head and neck region ofyoung adults.'4 The striking lymphoid andeosinophil reaction in both settings presumablyreflects continued antigenic stimulation. Caseswhich have been diagnosed as angiolymphoidhyperplasia and which were associated withprevious vaccinations should be examinedcarefully for the presence of the typical granu-lar histiocytes which should permit confidentdistinction between the two conditions. Adiagnosis of angiolymphoid hyperplasia shouldonly be made if the typical capillaries withconspicuous endothelial cells are a prominent

feature and no aluminium laden histiocytes arefound.

In summary, we report these cases to alerthistopathologists to the changes encounteredin aluminium injection site reactions and toemphasise that the lesions have a wider rangeof histological appearances than hitherto de-scribed.

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2 Clemmensen 0, Knudsen HE. Contact sensitivity toaluminium in a patient hyposensitized with aluminium-precipitated grass pollen. Contact Dermatitis 1980;6:305-8

3 Fischer T, Rystedt R. Case of contact sensitivity toaluminium. Contact Dermatitis 1982;8:343.

4 Johannessen H, Bergan-Skar B. Itching problems amongpotroom workers in factories using recycled alumina. Con-tact Dermatitis 1980;6:42.

5 Hall AF. Occupational contact dermatitis among aircraftworkers.JAMA 1974;125:179-85.

6 Medical Research Council Committee on the Clinical Trialof Influenza Vaccine. Second progress report: antibodyresponses and clinical reactions with saline and oil adjuvantvirus vaccine. BMJ 1955;2:1229-33.

7 Orell SR. Subcutaneous granulomata following inoculationof influenza vaccine. Acta Pathol Microbiol Immunol Scand1962;56: 127-34.

8 Slater DN, Underwood JC, Durrant TE, Gray T, HopperIP. Aluminium hydroxide granulomas: light and electronmicroscopic studies and x-ray microanalysis. Br3 Dermatol1982;107: 103-8.

9 Kaabar K, Nielsen AO, Veien NK. Vaccination granulomasand aluminium allergy: course and prognostic factors. Con-tact Dermatitis 1992;25:304-6.

10 Pembroke AC, Marten RH. Unusual cutaneous reactionsfollowing diphtheria and tetanus immunization. Clin ExpDermatol 1979;4:345-8.

11 Miliauskas JR, Mukherjee T. Postimmunization (vaccina-tion) injection-site reactions. A report of four cases andreview of the literature. Am J Surg Pathol 1993;17:516-24.

12 Akosa AB, Ali MH, Khoo CT, Evans DM. Angiolymphoidhyperplasia with eosinophilia associated with tetanustoxoid vaccination. Histopathology 1990;16:589-93.

13 Cox N, Moss C, Forsyth A. Allergy to non-toxoid constitu-ents of vaccines and implications for patch testing. ContactDermatitis 1988;18:143-6.

14 Mehregan AH, Shapiro L. Angiolymphoid hyperplasia witheosinophilia. Arch Dermatol 197 1;103:50-7.

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