Presented is an unusual case of a benign mesenchymal stromal tumor of the breast in an 81-yearold male. The basic appearance of the lesion simulated benign schwannoma and was misinterpreted as a low-grade myxoid liposarcoma initially. Well-circumscribed, gray-white mass measuring 35 mm in maximum diameter was discovered deep in the parenchyma of the completely removed breast. Microscopically, the lesion consisted of myxoid, richly vascular background where dominated oval or spindle cells with impressive palisading replicating that of benign schwannoma. Rarely, the large multinucleated (floret-like type) cells were visible; no nuclear atypia or mitotic figures were found. Immunohistochemical examination confirmed expression of estrogen and progesterone receptors, antigen Bcl2 and also focal desmin positivity. Clinical examinations disclosed no objective reason for possible hyperestrinism; no other therapy followed and the patient is free of disease 19 months after operation. On the background of both detailed review and differential diagnosis of benign, so-called stromal tumor of the female breast, the rarity of this microscopic finding in male is documented.

        Key words: male breast – mesenchymal lesion – benign stromal tumor – myofibroblastoma - schwannoma