Gynaecomastia is the benign proliferation of glandular tissue of the male breast. Most patients with gynaecomastia are asymptomatic. Symptomatic patients may present with breast or nipple pain or tenderness, breast enlargement, or a breast lump
Physiological causes
Infancy – 60–90% of infants have transient gynaecomastia due to oestrogenic stimulation from the mother and placenta (resolves neonatally)
Puberty – 30–60% of boys develop transient gynaecomastia (usually develops after the age of 10 years and resolves by age 17 years)
Aging – gynaecomastia is seen in an increasing number of normal adult men with increasing age (65% at age 80 years)
Pathological causes
Drug induced (therapeutic drugs)
Androgens
anabolic steroids
oestrogens and oestrogen agonists
cyproterone
cimetidine
digoxin
spironolactone
Drug induced (drugs of abuse)
Alcohol
Amphetamines
Heroin
marijuana
Liver cirrhosis
Malnutrition
Primary or secondary hypogonadism
Testicular tumours
Hyperthyroidism
Renal disease
Idiopathic – in 25% of cases of gynaecomastia, no specific cause is identified