[A case of metastatic breast tumors due to extraskeletal Ewing's sarcoma].

A 14 year-old woman was admitted to Tokyo Women's Medical College Daini Hospital complaining of lumps in bilateral breasts and right supraclavicular region. An excisional biopsy of right breast lump was done. Light- and electron-microscopic examination demonstrated abnormal cells containing many PAS-positive granules shich disappeared after diastase treatment. The diagnosis of Ewing's sarcoma was made immunohistologically using NSE, S-100, keratin, prekeratin, cytokeratin, desmin, epithelial membrane antigen and neurofilament. Whole body CT scan revealed large mass in the pelvic cavity considered as primary lesion. CYVADIC therapy was very effective. Breasts and supraclavicular lesions almost disappeared and pelvic lesion decreased in size.