Angiosarcoma of breast skin and parenchyma is a rarely reported complication of irradiation for breast carcinoma. We report a case of a subareolar epithelioid angiosarcoma arising 8 years subsequent to lumpectomy and irradiation of the ipsilateral breast for infiltrating carcinoma. The epithelioid appearance of the neoplastic cells on fine-needle aspiration biopsy (FNA) biopsy suggested a recurrence of the primary carcinoma. Careful attention to certain cytomorphologic features and cell block immunohistochemistry were useful in the distinction from recurrent carcinoma. Cytologic features that identified this neoplasm as an angiosarcoma included marked cell discohesiveness, elongate cytoplasmic processes or ''pseudopodia,'' heterogeneous cell size, large nucleoli or macronucleoli, and cytoplasmic lumina. Immunohistochemical markers, including Factor VIII antigen, CD31, and CD34, were positive, confirming the vascular nature of the neoplasm. Other markers ruled out morphologically similar neoplasms such as recurrent carcinoma and melanoma. Epithelioid angiosarcoma should be included in the differential diagnosis of a suspected recurrence of breast carcinoma several years postirradiation therapy. Diagn.