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Gynecomastia (GM) is a benign proliferation of the glandular component of the male breast caused by an increase in the ratio of estrogens to androgens. It presents as a palpable, concentric, and often painful subareolar mass and may be unilateral or bilateral. Although the finding of breast enlargement may be embarrassing or distressing to the patient, surgery for GM is rarely indicated, and cancer is present in less than 1% of patients. Gynecomastia is common. Two historical case series report 57% of healthy older men have GM, which increases to nearly 70% in hospitalized older men.1,2 Further, autopsy series found GM in 40% to 55% of unselected cases.3

Gynecomastia occurs physiologically with 3 natural peaks—in the neonatal period, puberty, and senescence. During the neonatal period, 60% to 90% of infants have transient breast enlargement due to maternal estrogen influence. By puberty, 50% to 75% of boys experience breast enlargement as estrogen concentrations peak earlier than the nearly 30-fold increase in testosterone concentrations.4 Most GM related to puberty spontaneously regresses within 2 years. Finally, as men age, free testosterone levels decline and obesity becomes more prevalent, increasing relative estrogen concentrations and therefore the incidence of GM.

Although GM is often physiologic, it may be idiopathic or associated with more serious disease, congenital syndromes, and/or medications (Tables 70-1 and 70-2).5 All result in either an increase in estrogen, decrease in androgen, or a deficit in androgen receptors. Nearly 75% of men seeking evaluation have idiopathic GM, persistent GM after puberty, or drug-induced GM.6

Table 70-1 Pathologic Causes of Gynecomastia
Table 70-2 Pharmacologic Causes of Gynecomastia

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 ...

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