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BACKGROUND: It is well known that subcutaneouslumps in the breast may create diagnostic confusion. Wereport, for the first time inthe cytologic literature, thefeatures of a pleomorphiclipoma in the breast.CASE: Pleomorphic lipomaof the breast was aspirated,showing typical floret cellsand mononuclear, hyper-chromatic cells with scal-loped nuclei, masqueradingas malignancy.CONCLUSION: Pleomorphic lipoma has rather typicalcytologic features that may allow its recognition whenthey are present in the proper clinical setting. This reportillustrates another diagnostic pitfall in fine needle aspi-ration biopsy of the breast. (Acta Cytol 2000;44:255–258)

Keywords: lipoma, pleomorphic; breast neoplasms;aspiration biopsy.

Fine needle aspiration (FNA) biopsy plays an im-portant role in the diagnosis of breast masses, but

there are considerable lim-itations when the neo-plasms are of mesen-chymal origin.5-7,9,11,12,14

Although the main pur-pose of soft tissue FNA isto separate benign andmalignant lesions, pleo-morphic lipoma (PL) hascharacteristic cytologic

features that may allow its recognition.In this paper we report an apparently unique PL

located in the subcutaneous breast tissue.

Case Report

A 53-year-old female presented with a four-yearhistory of a slowly growing mass in the upper outerquadrant of the left breast. Her past medical historywas not contributory. The axillary lymph nodeswere not palpable. Laboratory investigations werewithin normal limits. The lesion was considered be-nign after clinical and mammographic examina-tion. FNA biopsy of the mass was performed with a

From the Department of Pathology, Hospital Universitario “12 de Octubre” and Hospital “Severo Ochoa,” Madrid, Spain.

Drs. López-Ríos, Alberti and Pérez-Barrios are Staff Pathologists.

Dr. de Agustín is Chief, Cytology Service.

Address reprint requests to: Pedro P. de Agustín, M.D., Ph.D., F.I.A.C., Departamento de Anatomía Patológica, Hospital Universitario“12 de Octubre,” Carretera de Andalucía km. 5,400, 28041 Madrid, Spain.

Financial Disclosure: The authors have no connection to any companies or products mentioned in this article.

Received for publication December 21, 1998.

Accepted for publication March 2, 1999.

Aspiration Biopsy of Pleomorphic Lipoma ofthe BreastA Case Report

Fernando López-Ríos, M.D., Nuria Alberti, M.D., Ph.D., Andrés Pérez-Barrios, M.D.,M.I.A.C., and Pedro P. de Agustín, M.D., Ph.D., F.I.A.C.

Acta Cytologica

0001-5547/00/4402-0255/$19.00/0 © The International Academy of CytologyActa Cytologica

The need for extreme caution indiagnosis, particularly when thetumor is not in the usual clinical

setting,...cannot be overemphasized.

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22-gauge needle. The smears were fixed in 95%ethanol and stained with Papanicolaou stain. Sub-sequently the nodule was excised. The patient wasin good health when last seen, 12 months after theoperation.

Morphologic Findings

Smears contained fibrous and adipose tissue inter-spersed with clusters of hyperchromatic cells (Fig-ure 1) of two types: (1) mononuclear cells withscanty cytoplasm, showing occasional elongatedand indented nuclei (Figure 2); and (2) less frequentmultinuclear giant cells, exhibiting nuclei arrangedin a wreathlike configuration (“floret cells”) (Figure

3). The background was clean, without a significantnumber of inflammatory cells. Due to the presenceof these atypical cells, surgical excision was recom-mended.

The excised tumor was 3 × 2.5 cm, firm, well cir-cumscribed, yellow and solid. Histopathology re-vealed a typical PL (Figure 4) with numerous floretcells (Figure 5). No mitotic activity, mammary ele-ments, areas of necrosis or spindle cells were seen.

Discussion

PL is a distinct type of lipoma fully delineated byEnzinger in 1981. Its most common location is the

256 Acta CytologicaLópez-Ríos et al

Figure 1 Low-power view of the smears showing clusters ofdark cells attached to fragments of fibrous tissue (Papanicolaoustain, × 40).

Figure 3 Floret cell. Overlapping nuclei surround the cytoplasm, resembling the petals of a flower (Papanicolaou stain,× 400).

Figure 2 Some of the mononuclear cells exhibited an oval, scalloped nucleus (arrows) (Papanicolaou stain, × 100).

Figure 4 Pleomorphic lipoma. In addition to mature adipose tissue, there were a significant number of hyperchromatic cells(hematoxylin-eosin, × 40).

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shoulder and neck region. Local excision is thetreatment of choice, and the prognosis is excel-lent.2,15

To the best of our knowledge, only two otherwell-documented cases of PL had been reported inthe cytologic literature.3,13 Table I summarizes theirclinicopathologic findings. All the cases were con-sidered suspicious/positive for malignancy, main-ly because the smears contained no adipose tissue,or scarce or fragmented floret cells.3,13 The presenceof mononuclear cells with indented nuclei has beenunderscored in the literature since they are an im-portant clue.1,17-19 In addition, two more commentsmay be helpful to avoid pitfalls. First, the diagnosisof PL should not be rendered in deep-seated or rap-idly growing tumors, for liposarcoma and manyother malignant tumors may contain floretlike giantcells.3 Second, other nonneoplastic disorders show-ing multinuclear cells must be excluded, basedmainly on clinical data: tuberculosis, sarcoidosis,granulomatous mastitis, foreign-body granuloma,and so forth.8 Note that PL exhibits a clean back-ground.

In 1993 Lew reported on the cytologic features ofa breast tumor with floret and spindle cells; hecalled it “spindle cell lipoma.”10 The author consid-

ered the case identical to the entity described byToker et al in 1981 as “benign spindle cell breasttumor.”16 We think that the latter neoplasm mightrepresent examples of spindle cell lipoma arising inthe subcutaneous tissue of the breast. In this regard,our case must be viewed as a conventional PL lo-cated at an unusual site. It is necessary to rememberthat as Enzinger stated, “Transitional forms be-tween spindle cell and pleomorphic lipomas are notuncommon.”4

A specific diagnosis of “pleomorphic lipoma”should be suggested only when there is a good clin-ical and radiologic correlation. One should alwayskeep in mind that floretlike multinucleated giantcells are also present in malignant tumors. There-fore, the need for extreme caution in diagnosis, par-ticularly when the tumor is not in the usual clinicalsetting (a circumscribed, small mass in the subcuta-neous tissue that had been present for years), can-not be overemphasized.

References1. Åkerman M, Rydholm A: Aspiration cytology of lipomatous

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3. Dundas KE, Wong MP, Suen KC: Two unusual benign le-sions of the neck masquerading as malignancy on fine-nee-dle aspiration cytology. Diagn Cytopathol 1995;12:272–279

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5. González-Cámpora R, Muñoz-Arias G, Otal-Salaverri C,Jorda-Heras M, García-Álvarez E, Gómez-Pascual A, Garrida-Cintado A, Hevia-Vázquez A, Sánchez-Gallego F,Galera-Davidson H: Fine needle aspiration cytology of pri-mary soft tissue tumors: Morphologic analysis of the mostfrequent types. Acta Cytol 1992;36:905–917

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Volume 44, Number 2/March–April 2000 257Pleomorphic Lipoma of Breast

Figure 5 Floret cell. Hyperchromatic nuclei arranged at the periphery of the cell in a wreathlike fashion (hematoxylin-eosin,× 400).

Table I FNA Biopsy of Pleomorphic Lipoma: Summary of Reported Cases

Author (yr) Age/sex Site Size (cm) Duration Cytologic diagnosis Treatment

Rigby et al (1993)13 68/M Left supraclavicular area 1.2 6 mo Anaplastic carcinoma ExcisionDundas et al (1995)3 66/M Left supraclavicular area 3 6 mo Anaplastic carcinoma Excisional biopsyPresent case (1999) 53/F Left breast 3 4 yr Suspicious for malignancy Excisional biopsy

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13. Rigby HS, Wilson YG, Cawthorn SJ, Ibrahim NBN: Fine nee-dle aspiration of pleomorphic lipoma: A potential pitfall ofcytodiagnosis. Cytopathology 1993;4:55–58

14. Ryan M: Cytology and mesenchymal pathology?: How farwill we go? Am J Clin Pathol 1996;106:561–564

15. Shmookler BM, Enzinger FM: Pleomorphic lipoma: A be-nign tumor simulating liposarcoma. Cancer 1981;47:126–133

16. Toker C, Tang CK, Whitely JF, Berkheiser SW, Rachman R:Benign spindle cell breast tumor. Cancer 1981;48:1615–1622

17. Walaas L, Kindblom LG: Lipomatous tumors: A correlativecytologic and histologic study of 27 tumors examined by fineneedle aspiration cytology. Hum Pathol 1985;16:6–18

18. Willén H, Åkerman M, Carlén B: Fine neede aspiration(FNA) in the diagnosis of soft tissue tumors: A review of 22years experience. Cytopathology 1995;6:236–247

19. Woyke S, Kapila K, Goswami KC: Atypical lipoma as a po-tential pitfall in the cytodiagnosis of subcutaneous tumors: Areport of two cases. Acta Cytol 1997;41:897–902

258 Acta CytologicaLópez-Ríos et al

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