From the radiologic pathology archives: diseases of the male breast: radiologic-pathologic correlation.

Male breast disease includes a variety of benign and malignant conditions, many of which are hormonally influenced. Gynecomastia and skin lesions account for the majority of conditions in symptomatic men with a palpable abnormality, and these conditions should be accurately recognized. Imaging patterns of gynecomastia include nodular, dendritic, and diffuse patterns. Histopathologically, the nodular and dendritic patterns correlate with the florid and quiescent (fibrotic) phases of gynecomastia, respectively. The diffuse pattern may have features of both phases and is associated with exposure to exogenous estrogen. Benign-appearing palpable masses in male patients should be approached cautiously, given the overlapping morphologic features of benign and malignant tumors. In addition to gynecomastia, other benign male breast tumors include lipoma, pseudoangiomatous stromal hyperplasia, granular cell tumor, fibromatosis, myofibroblastoma, schwannoma, and hemangioma. Male breast cancer accounts for 1% of all breast carcinomas. Invasive ductal carcinoma accounts for the majority of cases in adult males and typically appears as a subareolar mass without calcifications that is eccentric to the nipple. Other epithelial and mesenchymal tumors that may occur, albeit not as commonly as in women, include papillary carcinoma, invasive lobular carcinoma, adenoid cystic carcinoma, liposarcoma, dermatofibrosarcoma, pleomorphic hyalinizing angiectatic tumor, basal cell carcinoma of the nipple, hematopoietic malignancies, and secondary tumors. Knowledge of the natural history, clinical characteristics, and imaging features of tumors that occur in the male breast will help narrow the radiologic differential diagnosis and optimize treatment.