Primary pleomorphic rhabdomyosarcoma of breast: Report of a rare neoplasm.

Primary sarcoma of the breast is very rare and constitutes less than 1% of all breast cancers. Herein, we report a case of pleomorphic rhabdomyosarcoma (PRMS) of the right breast in a 49-year-old female patient presented with a mass (7 cm × 6.5 cm). Mammography and ultrasonography suspected a malignant lesion and a diagnosis of poorly differentiated carcinoma was made on fine needle aspiration cytology. Modified radical mastectomy was carried out. Histopathological examination revealed a high grade stromal sarcoma with rhabdoid morphology and multinucleated tumor giant cells. The tumor cells were strongly positive for desmin, vimentin and Myo D1 focally. The tumor cells were immunonegative for cytokeratin, epithelial membrane antigen (EMA), CD34, CD45, SMA, S100, CD68 and HMB45. A final diagnosis of PRMS was rendered. Surgical margins were free and no metastasis was seen in axillary lymph nodes. Neither post-operative radiotherapy nor adjuvant chemotherapy was given and the patient has remained disease free 12 months post-operatively.