Primary hypogonadism results when there is damage to the testes (due to radiation, chemotherapy, infections, trauma, etc), leading to impaired androgen production. It can also be caused by chromosomal abnormality seen in Klinefelter syndrome, which is associated with gynecomastia in about 80% of cases. Secondary hypogonadism results when there is damage to the hypothalamus or pituitary (due to radiation, chemotherapy, infection, trauma, etc), and similarly lead to impaired androgen production. The net effect is reduced androgen production while serum estrogen levels (from peripheral aromatization of androgens) remain unaffected. The lack of androgen-mediated inhibition of breast tissue proliferation combined with relative estrogen excess result in gynecomastia. Tumors
Testicular tumors such as Leydig cell tumors, Sertoli cell tumors (such as in Peutz–Jeghers syndrome) and hCG-secreting choriocarcinoma may result in rapid-onset gynecomastia by causing excess production of estrogen. Other tumors such as adrenal tumors, pituitary gland tumors (such as a prolactinoma), or lung cancer, can produce hormones that alter the male–female hormone balance and cause gynecomastia.Individuals with prostate cancer who are treated with androgen deprivation therapy may experience gynecomastia. Pathophysiology
The causes of common gynecomastia remain uncertain, but are thought to result from an imbalance between the actions of estrogen, which stimulates breast tissue growth, and androgens, which inhibit breast tissue growth. Breast prominence can result from enlargement of glandular breast tissue, chest adipose tissue (fat) and skin, and is typically a combination. As in females, estrogen stimulates the growth of breast tissue in males.
During adolescence, on average 33 percent of males are estimated to exhibit signs of gynecomastia. Gynecomastia in older men is estimated to be present in 24–65 percent of men between the ages of 50 and 80. Estimates on asymptomatic gynecomastia is about up to 70% in men aged 50 to 69 years.The prevalence of gynecomastia in men may have increased in recent years, but the epidemiology of the disorder is not fully understood. The use of anabolic steroids and exposure to chemicals that mimic estrogen in cosmetic products, organochlorine pesticides, and industrial chemicals have been suggested as possible factors driving this increase. According to the American Society of Plastic Surgeons, breast reduction surgeries to correct gynecomastia are fairly common but has been a recent decline. In 2020, there were over 18,000 procedures of this type performed in the United States which is down 11% compared to in 2019. Society and culture
Gynecomastia can result in psychological distress for those with the condition. Support groups exist to help improve the self-esteem of affected people.In 2019, a 12-person Philadelphia jury awarded $8 billion in punitive damages to plaintiffs tied to the use of risperidone. Risperidone is an atypical antipsychotic that was originally approved to treat psychosis, but its use in children, including those with autism, ADHD, and schizophrenia diagnoses, has grown over the last two decades.In Murray v. Janssen Pharmaceuticals, Murray was a Risperidone user who was prescribed the medication at age nine and developed male breasts.