Myofibroblastoma: a potential pitfall in core needle biopsy of breast lesions.

Myofibroblastoma (MFB) is a benign neoplasm arising most frequently in the adult breast, but it may occur in any other tissue with the exception of the central nervous system. Adequate treatment of this neoplasm consists of local excision. MFB shows characteristic histological features and a clear immunohistochemical profile and usually does not cause any diagnostic difficulties [1-4]. A rare variant of MFB such as the epithelioid subtype with sclerotic stroma, however, can resemble lobular carcinoma in routinely stained histological sections.