An Unusual Case of Fibromatosis of the Axilla

Abstract

because of pure osteosarcomatous component without epithelial elements and no connection between this tumor and underlying skeleton in imaging methods.We thought that there was a simple and unusual coexistence of benign CSP in one breast and pure osteosarcoma in the contralateral breast in our patient.A 36-year-old female presented with an enlarging left axillary mass and otherwise normal examination. Mammography was normal and a trucut biopsy inconclusive. Magnetic resonance imaging scan (a) (b) Figure 2. (a) Hypercellular tumor with osteoid deposits is seen in the lower half of the field. Normal breast ductal elements compressed by the tumor bulk are noted above (H&E, 100·). (b) Osteosarcomatous component with atypical osteoblastic proliferation, nuclear pleomorphism, and osteoid deposits (arrows) separated from compressed mammary parenchyma and ductal structures (H&E, 400·).(a) (b) Figure 3. (a) Benign cystosarcoma phyllodes. Ductal elements with narrow lumens compressed in hypocellular uniform stroma are seen (H&E, 100·). (b) High-power view of benign cystosarcoma phyllodes. Breast ductules are seen in fibroblastic stroma consisting of fusiform cells with no cellular atypia and no mitoses (H&E, 200·).