Triple-negative metaplastic breast carcinoma with extensive squamous differentiation in a 55-year-old woman: A rare entity

The World Health Organization in 2003 classified the metaplastic breast carcinomas into, pure epithelial metaplastic carcinomas and mixed epithelial/mesenchymal metaplastic carcinomas, which comprises of squamous cell carcinoma, adenocarcinoma with spindle cell metaplasia, adenosquamous carcinoma, and mucoepidermoid carcinoma in the former and only mixed types in the latter. Metaplastic carcinoma is a rare form of cancer which accounts for <1% of invasive breast cancer and is characterized by areas of metaplasia typically with squamous, spindle, osseous, or chondroid differentiation in the background of adenocarcinoma. We are presenting a case of a 55-year-old female with a fungating, ulceroproliferative mass involving her whole breast including the nipple areola complex which turns out to be a rare form metaplastic breast carcinoma with extensive squamous differentiation.