Spindle cell carcinoma of male breast: Report of a rare case

We report a rare case of spindle cell carcinoma, a histological subtype of metaplastic breast carcinoma, in a 40-year-old male who presented with an ulcero-proliferative lump in the right breast. Fine-needle aspiration cytology of the lesion showed poorly cohesive clusters of pleomorphic spindle-shaped cells, suggestive of malignant spindle cell tumor. Right mastectomy along with ipsilateral lymph node dissection was performed. Microscopic evaluation revealed a neoplasm comprising interlacing fascicles of oval to spindled pleomorphic cells with brisk mitosis and areas of necrosis. There was no nodal metastasis. Immunohistochemistry revealed a triple-negative phenotype along with diffuse positivity for CK5/6, vimentin, and smooth muscle actin. p63, beta-catenin, and CD34 were negative. The patient subsequently received adjuvant chemotherapy with 5-fluorouracil, adriamycin, and cyclophosphamide regimen and was disease-free at 1-year follow-up.