Extra-abdominal desmoid mimicking malignant male breast tumor

A rare case of extra-abdominal desmoid tumor is reported. A palpable mass was detected in the right breast of a 47-year-old man. Mammography showed a stellate mass without calcification, and breast ultrasound examination revealed a solid, inhomogeneous, non-calcified lesion. The result of cytological examination of the fine-needle aspiration biopsy specimen was equivocal. Histology of the surgical specimen showed extra-abdominal desmoid tumor. Extra-abdominal presentation of this semimalignant tumor is rare and may mimic malignant breast tumor. Differential diagnosis is difficult and usually based on the result of the histological examination.