At puberty various processes contribute to the development of gynaecomastia:
- a surge of gonadotrophins induces testicular activity
- oestrogen production by the Leydig cells of the testicle reaches adult levels before that of testosterone
- also the peripheral aromatization of weak testicular and adrenal androgens to oestrone and oestradiol, this leads to a relatively low androgen to oestrogen ratio, and development of gynaecomastia development
Pubertal gynaecomastia is a common finding in boys:
- seen in 38 % of boys aged 10-16 years; reaching a peak of 65% in 14-year-olds (1)
- the gynaecomastia is generally transitory - pubertal gynaecomastia resolves in 73% of boys after 2 years and 92% after 3 years (1)
- 25% or more of pubertal gynaecomastia are unilateral, and where bilateral, are normally of different degrees - this finding is suggestive of a variation in local factors, possibly related to hormone receptors or local hormone conversion.
Several types of pubertal gynaecomastia are recognised (2):
- benign adolescent hypertrophy - in this form of pubertal gynaecomastia there is firm, somewhat tender breast tissue immediately beneath the areola; this is the most common form of pubertal gynaecomastia
- gynaecomastia resembling normal female breast development - this may require surgical intervention if there is enduring physical distress
- gynaecomastia associated with other pathology e.g. endocrine disorders such as hyperthyroidism, Klinefelter's syndrome or drug ingestion. This type of puberty associated gynaecomastia is rare
Where gynaecomastia is clearly neonatal or pubertal, no investigation is required (1).
With the exception of Klinefelter’s syndrome, pubertal gynaecomastia is not associated with an increased risk of male breast cancer (1)
Reference:
- Gately CA. Male breast disease.The Breast (1998) 7, 121-127.
- Robinson MJ and Roberton DM (Eds). Practical Paediatrics. Churchill Livingstone.