title: Mammary epithelioid myofibroblastoma arising in bilateral gynecomastia: case report with immunohistochemical profile.
abstract: Myofibroblastoma of the breast is a rare benign neoplasm, which has rarely been reported in association with gynecomastia. We report a case of a 25-year-old male patient with an epithelioid myofibroblastoma arising in a context of bilateral gynecomastia. The lesion was composed of nests and cords of epithelioid cells, with round to oval nuclei, granular chromatin, and distinct nucleoli dispersed in a myxoid to collagenous stroma with marked vascular proliferation. Immunohistochemical profile showed diffuse positivity for vimentin and focal immunoreactivity for desmin, whereas cytokeratins (CAM5.2 and AE1/AE3), EMA, alpha smooth muscle actin, actin HHF35, CEA, S100, factor VIII, neuron-specific enolase, CD31, and CD34 were all negative. We emphasize that this diagnosis is difficult to establish, owing to the rarity of this variant and clinical presentation.
authors.affiliation: Institute of Molecular Pathology and Immunology of University of Porto, Portugal.
authors.forename: J S
authors.initials: JS
authors.lastname: Reis-Filho
authors.forename: L N
authors.initials: LN
authors.lastname: Faoro
authors.forename: E L
authors.initials: EL
authors.lastname: Gasparetto
authors.forename: J T
authors.initials: JT
authors.lastname: Totsugui
authors.forename: F C
authors.initials: FC
authors.lastname: Schmitt
mesh_terms: D000328:Adult; D018567:Breast Neoplasms, Male / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D003893:Desmin / Q000378:metabolism; D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology; D006177:Gynecomastia / Q000150:complications*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D015674:Mammary Neoplasms, Animal / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D009379:Neoplasms, Muscle Tissue / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D014746:Vimentin / Q000378:metabolism
chemical_list: D003893:Desmin; D014746:Vimentin