A 14-year-old boy is brought to the office due to right breast enlargement. The patient says that he developed mild tenderness of the area 3 months ago and is distressed by its appearance. He is otherwise healthy and takes no daily medications. The patient does not use alcohol or recreational drugs. Height and weight are at the 80th and 60th percentile, respectively. Temperature is 36.7 C (98.1 F) and blood pressure is 112/62 mm Hg. Physical examination shows mild facial acne and the presence of hair on the upper lip and in the axillae. The right breast is enlarged with a 2-cm, firm, mildly tender mass under the nipple-areolar complex. There is no associated erythema or adenopathy. No palpable masses are present on the left. External genitalia are consistent with sexual maturity rating (Tanner stage) 4. The remainder of the examination is unremarkable. Which of the following is the best next step in management of this patient's condition?
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This adolescent most likely has physiologic gynecomastia, a benign condition affecting approximately half of boys during midpuberty (eg, sexual maturity ratings 2-4). Characteristic features include unilateral or bilateral breast enlargement that is directly under the nipple-areolar complex, is often tender, and measures <4 cm.
The mechanism of physiologic gynecomastia is likely multifactorial:
Imbalance of estradiol and testosterone: During early male puberty, adrenal androgens increase (ie, adrenarche) and are converted by aromatase to estrogens, which stimulate growth of glandular breast tissue. Testosterone, which is produced by the testes and inhibits the development of breast tissue, typically remains low until full maturation of the hypothalamic-pituitary-gonadal axis. This may cause a transient estrogen excess, and some patients may be prone to gynecomastia because of a greater local concentration of aromatase.
Higher insulin-like growth factor 1 (IGF-1) levels: Boys with physiologic gynecomastia have higher serum IGF-1, which stimulates glandular breast tissue, than those without, resulting in a further imbalance of prostimulatory hormones.
Diagnosis is clinical, but all adolescents should also be screened for substance use (eg, marijuana, alcohol, anabolic steroids), as was done in this patient, because it may contribute to gynecomastia. Management of physiologic gynecomastia includes observation and reassurance that it typically self-resolves within a year; frequent follow-up may be required for patients with psychosocial stress (eg, low self-esteem).
(Choices A, C, and D) Pathologic gynecomastia should be suspected in patients who develop breast tissue outside of midpuberty or who have rapidly enlarging tissue or tissue >4 cm. Evaluation may include a serum hormone panel (eg, hCG, LH, estradiol, testosterone) to evaluate for pathologic hormone imbalance. For example, low testosterone levels suggest hypogonadism and may warrant karyotyping to evaluate for Klinefelter syndrome (47,XXY) and/or serum prolactin to assess for a prolactin-secreting tumor. This patient's stage 4 pubic hair and otherwise normal examination make physiologic gynecomastia much more likely.
(Choice B) Mammography may be indicated for findings concerning for breast cancer, such as a fixed, nontender mass outside of the nipple-areolar complex with associated skin dimpling, nipple discharge, or adenopathy. Breast cancer is exceedingly rare in adolescent boys, and this patient has no red-flag findings.
Educational objective:
Physiologic gynecomastia is a benign condition caused by a transient proestrogenic hormonal imbalance during midpuberty; it presents in adolescent boys with unilateral or bilateral tender breast enlargement. Patients should be reassured that the condition typically self-resolves within a year.