ESSENTIALS OF DIAGNOSIS
Palpable enlargement of the male breast, often asymmetric or unilateral.
Glandular gynecomastia: typically tender.
Fatty gynecomastia: typically nontender.
Must be distinguished from carcinoma or mastitis.
Gynecomastia is defined as the presence of palpable glandular breast tissue in males. Pubertal gynecomastia develops in about 60% of boys; the swelling usually subsides spontaneously within a year. It is particularly common in teenagers who are very tall or overweight. The causes are multiple and diverse (Table 26–13). About 20% of adult gynecomastia is caused by drug therapy. It can develop in HIV-infected patients treated with antiretroviral therapy, especially in men receiving efavirenz or didanosine; breast enlargement resolves spontaneously in 73% of patients within 9 months. Gynecomastia develops in about 50% of athletes who abuse androgens and anabolic steroids. Fatty pseudogynecomastia is common among elderly men, particularly when there is associated weight gain. However, true glandular gynecomastia can be the first sign of a serious disorder in older men (Table 26–13).
Table 26–13.Causes of gynecomastia. |Favorite Table|Download (.pdf) Table 26–13. Causes of gynecomastia.
Neonatal period, puberty
Androgen insensitivity syndrome
Aromatase excess syndrome (sporadic or familial)
Diabetic lymphocytic mastitis
Hyperthyroidism or hypothyroidism
Male hypogonadism (primary or secondary)
Partial 17-ketosteroid reductase deficiency
Chronic liver disease
Chronic kidney disease
Refeeding after starvation
Spinal cord injury
Ectopic hCG: CNS germinoma, lung, hepatocellular, gastric, renal carcinomas
Testicular hCG-secreting tumors
Drugs (partial list)
Alkylating chemotherapeutic agents
Antipsychotics (first- and second-generation)
Calcium channel blockers (rare)
Estrogens (oral or topical)
Lavender oil and fragrances (topical)
Proton pump inhibitors (uncommon)
Selective serotonin reuptake inhibitors (SSRIs)
Tea tree oil (topical)
The male breasts must be palpated carefully to distinguish firm true glandular gynecomastia from softer fatty pseudogynecomastia in which only adipose tissue is felt. The breasts are best examined both seated and supine. Using the thumb and forefinger as pincers, the subareolar tissue is compared to nearby adipose tissue. Fatty tissue is usually diffuse and nontender. True glandular enlargement beneath the areola may be tender. Pubertal gynecomastia is characterized by tender discoid enlargement of breast tissue 2–3 cm in diameter beneath the areola. The following characteristics are worrisome for malignancy: asymmetry; location not immediately below the areola; unusual firmness; or nipple retraction, bleeding, or discharge. The examination must also include an assessment of masculinization, examination of the testes ...