Gynecomastia

Nolan S. Karp

Gynecomastia is enlargement of the male breast and is caused by an increase in ductal tissue, stroma, and/or fat. Most frequently, the changes occur at the time of hormonal change: infancy, adolescence, and old age.

The term gynecomastia was introduced by Galen during the 2nd century AD and the surgical resection was first described by Paulis of Aegina1^,2 in the 17th century AD.

ETIOLOGY

The most common cause of gynecomastia is unknown (idiopathic). The other common causes of gynecomastia are listed in Table 57.1. Gynecomastia often appears transiently at birth. The process is thought to be related to an increased level of circulating maternal estrogens. After birth, the estrogen level decreases, the gynecomastia resolves, and treatment is rarely necessary.

TABLE 57.1 COMMON CAUSES OF GYNECOMASTIA

Idiopathic
Obesity
Physiologic
	Birth
	Puberty
	Old age
Endocrine
	Testis: hypogonadism, Klinefelter syndrome
	Adrenal: Cushing syndrome, congenital adrenal hyperplasia
	Thyroid: hypothyroid, hyperthyroid
	Pituitary: pituitary failure
Neoplasms
	Adrenal
	Testis
	Pituitary
	Bronchogenic
Systemic diseases
	Renal failure
	Cirrhosis
	Adrenal
	Malnutrition
Drug-induced
	Hormones: estrogens, androgens
	Antiandrogens: spironolactone, cimetidine, ketoconazole, ranitidine, flutamide
	Cardiovascular drugs: amiodarone, digoxin, nifedipine, reserpine, verapamil
	Abused drugs: Alcohol, heroin, marijuana

Gynecomastia is said to occur in almost two-thirds of adolescent boys.3 This is thought to be due to an imbalance of estradiol and testosterone. The adolescent gynecomastia also resolves in the vast majority of cases.2 In some cases, a degree of gynecomastia remains, but is not problematic enough to warrant medical attention. In the adolescent male, obesity is frequently associated with enlarged breasts. This may be due to the elevated levels of estrogen.4 The initial treatment is weight loss, but if this is not successful, surgical correction may be indicated.

The incidence of gynecomastia rises again in older men (age > 65 years). This is thought to be due to a decline in testosterone and a shift in the ratio of testosterone to estrogen.

In all three age groups (neonatal, adolescent, and older men), gynecomastia appears to be related to either an increase in estrogens, a decrease in androgens, or a deficit in androgen receptors.2 There are also numerous drugs and medications that cause gynecomastia (Table 57.1). Systemic causes include adrenal diseases, liver diseases, pituitary tumors, thyroid disease, and renal failure. Tumors of adrenal, pituitary, lung, and testis can be associated with hormonal imbalance resulting in gynecomastia.

In any male patient with breast enlargement, breast cancer must be considered since 1% of all breast cancers occur in men. There is no increased risk of breast cancer in patients with gynecomastia when compared with the unaffected male population.5 The exception is patients with Klinefelter syndrome. These patients have an approximately 60 times increased risk of breast cancer.

PATHOLOGY

Three types of gynecomastia have been described: florid, fibrous, and intermediate.6 The florid type is characterized by an increase in ductal tissue and vascularity. A minimal amount of fat is mixed with the ductal tissue. The fibrous type has more stromal fibrosis with few ducts. The intermediate type is a mixture of the two. The type of gynecomastia is usually related to the duration of the disorder. Florid gynecomastia is usually seen when the breast enlargement is of new onset within 4 months. The fibrous type is found in cases where gynecomastia has been present for more than 1 year. The intermediate type is thought to be a progression from florid to fibrous and is usually seen from 4 to 12 months.6^,7

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