LETTER TO THE EDITOR

Fine-Needle Aspiration Cytologyin Neurilemoma (Schwannoma)of the Breast:Report of Two Cases in a Man and a Woman

Dear Dr. Bedrossian:Schwannoma (neurilemoma) is a slow-growing tumor and

is commonly found in the neck, head, and flexor surfaces of theextremities. Its occurrence in the breast is very unusual,1–9 anda diagnosis using fine-needle aspiration cytology (FNAC) hasonly been reported in a few studies in female patients5,7–9andin a single case report in a male patient.6 In this communicationwe report on 2 cases of schwannoma (neurilemoma) of thebreast in a male and a female with immunocytochemicalfindings (Table I). The aspirate was obtained using a dispos-able 10-ml syringe and 22-gauge disposable needle, usingmultiple passes in the mass, maintaining negative pressure.The aspirated material was collected as needle and syringewashings in 30% ethyl alcohol in physiologic saline. From halfof this material, filter preparations were made on 3-mm sizeSchleicher and Schuell filters and stained by the Papanicolaoumethod. The remainder of the needle and syringe washingswere centrifuged, and cell blocks were made, fixed, embedded,cut at 5mm, and stained with hematoxylin-eosin. Sections ofcell block were further utilized for immunostaining for S-100protein by the immunoperoxidase method, using a commer-cially purchased kit. Known positive and negative controlswere used during the immunostaining procedure. Papanico-laou-stained filter preparations in both cases showed oval,elongated, and interlacing spindle-shaped cells that were dis-sociated or in small clusters, with suggestion of nuclear pali-sading with faintly eosinophilic cytoplasm and ill-defined cy-toplasmic borders (Fig. 1A). Sections of cell blocks showedinterlacing bundles of spindle-shaped cells, arranged in a pal-isading pattern with occasional Verocay bodies (Fig. 1B).Immunopositivity for S-100 protein antibody was noted inboth cases.

Since the utility of FNAC in the preoperative diagnosis ofsoft-tissue tumors is documented,10,11it would appear that acytodiagnosis of schwannoma may be possible on observingdissociate and clusters of interlacing bundles of spindle-shaped cells, arranged in a palisading pattern in cytologicpreparations and sections of cell blocks from the aspiratewith Verocay bodies. This was true in both cases presented

here. However, in the absence of Verocay bodies, the cy-todiagnosis can present difficulty, since some mesenchymalneoplasms comprising smooth cells and with fibromatousfeatures can show spindle cells and nuclear palisading.12,13

Breast enlargement due to an intramammary schwannomacan also present diagnostic difficulties clinically and cytolog-

Fig. 1. A: Papanicolaou-stained filter preparation, showing spindle-shapedcells arranged in a palisading pattern (3250). B: Hematoxylin-eosin-stained section of a cell block, showing histological features of schwan-noma with palisading of nuclei and some Verocay bodies (3125).

76 Diagnostic Cytopathology, Vol 24, No 1 © 2001 WILEY-LISS, INC.

ically when spindle cells are found in an aspirate, since suchenlargement may be mistaken for some benign and malignanttumors. In differential diagnoses, phylloides tumor, fibromato-sis, neurofibroma, myoepithelioma, leiomyoma, metaplasticcarcinomas, and low-grade malignant spindle-cell tumors withatypias may need to be considered. These have been ade-quately discussed in other studies with which we are in agree-ment.5–8 Other possible clues which have been considereduseful for the diagnosis of schwannoma include lack of epi-thelial elements within the tumor, absence of mitotic activity,nuclear palisading, and positivity of S-100 protein. In both ourcases such findings were noted. We also agree with Silvermanet al.11 that ancillary studies are especially useful in differen-tiating spindle-cell lesions of the breast.

In conclusion, we feel that in an aspirate sample from abreast mass with spindle-cell features, the diagnosis of aschwannoma should be considered. Also, the lack of mitoticactivity, palisading features, positive staining for S-100 pro-tein, and use of cell blocks showing histologic features withVerocay bodies are useful in determining the correct diagnosis.

Raj K. Gupta,M.D., F.I.A.C.

Sarla Naran,B.Sc., C.F.I.A.C.

Sharda Lallu,B.Sc., C.F.I.A.C.

Robert Fauck,C.T. (I.A.C.)

Cytology UnitDepartment of Laboratory ServicesWellington Hospital and School of MedicineWellington, New Zealand

References1. Collins R, Gau G. Neurilemoma presenting as a lump in the breast.

Br J Surg 1973;60:242–243.2. Majumdar B. Neurilemoma presenting as a lump in the breast. South

Med J 1976;69:463–464.

3. Krishnan MMS, Krishnan R. An unusual breast lump: neurilemoma.Aust N Z JSurg 1982;52:612–613.

4. Van der Walt JD, Reid HAS, Shaw JHF. Neurilemoma appearing as alump in the breast. Arch Pathol Lab Med 1982;106:539–540.

5. Fisher PE, Estabrook A, Cohen MB. Fine needle aspiration biopsy ofintramammary neurilemoma. Acta Cytol 1990;34:35–37.

6. Matinez-Onsurbe P, Fuentes-Vammonde E, Gonzalez-Estecha A, Her-nandez-Oritz MJ, Raiz-Villaespesa A. Neurilemoma of the breast in aman. A case report. Acta Cytol 1992;36:511–513.

7. Bernardello F, Caneva A, Bresada E, Mombello A, Zamboni G,Bonetti F, Lannucci A. Breast solitary schwannoma: fine-needle aspi-ration biopsy and immunocytochemical analysis. Diagn Cytopathol1994;10:221–223.

8. Galant C, Mazy S, Berliere M, Mazy G, Wallon J, Marbix E. Twoschwannomas presenting as lumps in the same breast. Diagn Cyto-pathol 1997;16:281–283.

9. Matsuda M, Sone H, Ishiguro S, Kabato T, Hayashi H. Fine needleaspiration cytology of malignant schwannoma metastatic to the breast.Acta Cytol 1989;33:372–376.

10. Layfield LJ, Anders KH, Glasgow BJ, Mirra JM. Fine needle aspira-tion of primary soft tissue lesions. Arch Pathol Lab Med 1986;110:420–424.

11. Silverman J, Geisinger KR, Frable WJ. Fine-needle aspiration ofmesenchymal tumors of the breast. Diagn Cytopathol 1988;4:50–58.

12. Harkin JC, Reed RJ. Tumours of peripheral nervous system. In: Atlasof tumor pathology, second series, fascicle 3. Washington, DC: ArmedForces Institute of Pathology; 1969. p 29–65.

13. Neifer R, Nguyen GK. Aspiration cytology of solitary schwannoma.Acta Cytol 1985;29:12–14.

Table I. Summary of Findings in Two Cases of Neurilemoma of the Breasta

Case Age (yr), sex Clinical findingsClinical

diagnosisFNA and histologicdiagnosis (F and C)

Immunostainingresults

1 35, M Discrete thickening 23 1.5 cm in uppermedial left breast of 4 wk duration

Gynecomastia? Schwannoma S1001

2 56, F Discrete 33 2 cm lump right (lateral)breast for 2 wk

Fibroadenoma? Schwannoma S1001Carcinoma?

aF, filter preparation; C, cell block;1, positive.

NEURILEMOMA (SCHWANNOMA) OF THE BREAST

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