Male Mammary Myofibroblastoma Masquerading as Malignancy.

We report a case of myofibroblastoma (MFB) of the breast in a 58-year-old man who presented with a large painless lump in the left breast. Radiologic breast imaging showed a well-circumscribed mass with no microcalcifications. Microscopic examination revealed fascicles of spindle cell neoplasm with intervening thick bundles of hyalinized collagen and interspersed vessels. Pertinent immunohistochemistry markers showed positivity for CD34, estrogen receptor, progesterone receptor and androgen receptor. A diagnosis of MFB of the breast was rendered. It is crucial to differentiate MFB from other entities in the breast like fibroadenoma, phyllodes tumor, gynecomastia, carcinoma and sarcoma for its appropriate management.