[A case of spindle cell carcinoma of the breast]

A forty-year-old woman noticed a mass in her right breast. In April, 1984, a radical mastectomy was performed and the specimen was subjected to histopathological and ultrastructural study. The well-localized tumor revealed atypical spindle cell nests in the desmoplastic stroma. Based upon a squamous differentiation of the cancer cell nests, the tumor was diagnosed as spindle cell carcinoma. The histogenesis and prognosis of this rare tumor are discussed and the myoepithelial origin is suggested.