The etiology of GM is frequently ascertained simply by comprehensive clinical evaluation, including history and physical examination. Attention must be given to a complete review of systems and medication evaluation. Frequently in long-standing GM no further evaluation is necessary. Gynecomastia of recent onset typically presents as a tender, smooth, mobile, rubbery mass centrally within the breast with a normal appearance to the overlying skin, nipple, and areola. In contrast, breast cancers are hard, ill-defined masses, and they may be associated with skin flattening or retraction. Nipple bleeding or discharge may be present in up to 10% of men with breast cancer.7 Gynecomastia can be unilateral or bilateral, and although unilateral GM must be differentiated from breast cancer, the overwhelming proportion of unilateral breast masses in men are benign. However, the physical findings of GM and early breast cancer may be quite similar, and any persistent breast mass of recent onset requires further evaluation.