Gynecomastia in the pubertal male

- 2/3 of teen males
- mean age of onset: 13
- usually unilateral, 75% may develop bilateral
- less than 4 cm
- usually resolves 12-18 mos
- PE, look for size of testes, masses. Doughnut sign.

Pubertal gynecomastia is a benign and self-limited increase in glandular and stromal tissue that is believed to result from a temporary alteration in the ratio of estrogen to testosterone. Approximately two thirds of adolescent males develop pubertal gynecomastia. The mean age of onset is 13 years, and 50% of patients are at Sexual Maturity Rating (Tanner) stage 3 development when breast enlargement begins. Although the condition initially is unilateral, more than 75% of affected boys eventually develop bilateral gynecomastia.

Physical examination reveals a mobile, firm, rubbery nodule located beneath the areola, as described for the boy in the vignette. In some affected boys, breast tissue extends beyond the areolar border, but it is rare for glandular tissue to exceed 4 cm in diameter. Pubertal gynecomastia usually resolves within 12 to 18 months; in only 8% of boys does it persist beyond 2 years.

Many other conditions may produce gynecomastia or physical findings that mimic breast enlargement. Most of these can be differentiated from pubertal gynecomastia by associated symptoms or signs and the results of physical examination, including evaluation of the genitalia. Adolescents who have Klinefelter syndrome (46 XXY) exhibit gynecomastia, but unlike the patient presented in the vignette, are tall and have small testes. A testicular carcinoma can secrete estrogens or increase the conversion of androgen precursors to estrogen, resulting in gynecomastia, but this diagnosis should be suspected based on the finding of a testicular mass. Although chest wall lipomas may mimic gynecomastia, they usually are not located directly beneath the areola. In obese patients, adipose tissue may be confused with breast tissue. On palpation, this "pseudogynecomastia" can be distinguished from breast tissue because adipose tissue has a less "ropy" feel than breast tissue. In addition, when adipose tissue is present, palpation in the supine position often reveals a subareolar depression surrounded by firm tissue (the "doughnut  sign").

References:
Braunstein GD. Gynecomastia. N Engl J Med. 1993;328:490-495
Neinstein LS. Gynecomastia. In Adolescent Health Care. A Practical
Guide. 3rd ed. Baltimore, Md: Williams & Wilkins; 1996:210-214