Myofibroblastoma associated with bilateral gynecomastia: a case report and literature review.

Myofibroblastoma of the breast is a recently recognized benign mesenchymal mammary tumor that typically occurs as a unilateral, solitary lesion. Myofibroblastomas are well-circumscribed, unencapsulated tumors characterized by spindle cells in fascicles which exhibit varying degrees of myogenic and fibroblastic differentiation. Our case reports a mammary myofibroblastoma occurring in an 82-year-old male with gynecomastia and reviews the reported incidence of this benign spindle cell tumor in the world literature.