In girls, puberty may already start at the age of 8 years, with breast enlargement as its first sign. In boys, respectively, puberty may start at the age of 9 years, and gynaecomastia may appear at any phase of puberty.
Independent thelarche, i.e. breast growth without progressive puberty is often seen especially in girls, usually at the age of 2 to 3 years but it may also occur at any other time during the years preceding puberty. In boys this phenomenon is more rare but possible especially during the first year of life.
In children with independent thelarche it should be ensured that the child does not have progressive puberty which would require further investigations and treatment. If there is an acceleration of growth and the breasts continue to enlarge, investigations for precocious puberty are warranted; see Pubertal Development and its Disturbances.
As many as every second elderly overweight man has gynaecomastia. This is probably caused by androgens metabolised into oestrogens in adipose tissue.
Pathological breast enlargement
For gynaecomastia of puberty, see Pubertal Development and its Disturbances.
Hormonal breast growth is caused by oestrogen-androgen dysequilibrium in men.
Is the condition in question gynaecomastia or pseudogynaecomastia (growth of subareolar adipose tissue but not of glandular tissue)?
Differential diagnosis between gynaecomastia and breast cancer (gynaecomastic tissue is soft and elastic and is deposited right beneath the areola, bilateral in 50% of cases; cancer tissue is solid or hard, not beneath the areola, often unilateral)
For gynaecomastia of puberty, see Pubertal Development and its Disturbances.
Because gynaecomastia is often transient and the aetiology can be determined in only about half of all cases, not all patients need hormone assays. Investigations are indicated if the drugs used by the patient do not explain the gynaecomastia, and
the breast is tender (a sign of rapid growth) or
the diameter of the breast tissue is > 4 cm.
In other cases the need for investigations is decided individually. For example, gynaecomastia associated with signs of androgen deficiency should always be investigated.
If serum LH concentration is increased and serum testosterone concentration decreased the patient probably has testosterone deficiency caused by testicular dysfunction.
If serum testosterone concentration is decreased and serum LH is normal or decreased the patient probably has hypogonadotrophic hypogonadism or increased oestrogen production.
If both serum LH and free testosterone concentrations are increased the patient has androgen resistance or a rare gonadotrophin-secreting tumour of the pituitary gland.
Serum beta-hCG concentration is increased in testicular trophoblast tumours.
In problematic cases the following tests can be performed according to specialist advice:
serum oestrone and prolactin
liver function tests
karyotype
mammography or breast ultrasonography in order to determine breast structure or detect eventual tumours.
Treatment
In transient gynaecomastia the breast usually decreases in size spontaneously after the underlying cause has been corrected.