Primary Stromal Sarcoma of Breast With Malignant Fibrous Histiocytoma-like Features Causing Diagnostic Dilemma on Fine-Needle Aspiration Cytology in a Patient With Squamous Cell Carcinoma of Cervix: A Case Report

A variety of malignant spindle-cell tumors are known to occur in the breast, which are collectively referred to as "breast spindle-cell tumors.'' Their interpretation on fine-needle aspiration cytology (FNAC) can be highly tricky. Here, we report a case. A 47-year-old female presented with a hard, mobile lump in the right breast for 4 months. Five years previous to this, she was treated with radiotherapy for squamous-cell carcinoma (SCC) of cervix. FNA of the breast lump showed high-cell yield with clusters, fascicles, and dissociated cells displaying spindle-cell morphology, with marked pleomorphism, many bizarre uninucleate/multinucleate giant cells, and a striking mitotic activity. At places, the cells in a necrotic background simulated keratinized squamous cells. Considering the past history of SCC of cervix, the first possibility of metastatic SCC with a differential diagnosis of metaplastic carcinoma, malignant phylloides, and a primary sarcoma of the breast was considered. Subsequent trucut/excision biopsy with appropriate immunomarkers revealed it to be a case of primary stromal sarcoma of the breast with malignant fibrous histiocytoma (MFH)-like features. Malignant spindle-cell tumor of breast in a patient with SCC of cervix (which also has a tendency to manifest with spindle cell morphology) can cause genuine diagnostic difficulty. In such patients, use of appropriate panel of markers is mandatory for dis-tinguishing between the metastatic SCC from cervix and other more commonly occurring spindle-cell malignancies of the breast. Diagn. Cytopathol. 2011;39:223-228. (C) 2010 Wiley-Liss, Inc.