Gynecomastia is a common clinical condition. It is generally considered abnormal in males except for 3 conditions: transient mastopexy in newborns: enlarged mammary glands during puberty: occasional mastopexy in older males; palpable breast tissue is considered abnormal. Common symptoms The appearance of enlarged breast tissue, nipples, and areolas. Etiology Breast development in men is due to either increased estrogen production or a decrease in the androgen/estrogen ratio. Excessive estrogen is the main cause of gynecomastia. Exogenous estrogen preparations given to men, such as estrogen therapy for prostate cancer patients, long-term estrogen use in transsexual men, and excessive estrogen secretion from adrenal or testicular tumors can lead to gynecomastia. Clinical manifestations Men present with unilateral or bilateral palpable breast tissue in the form of disc-shaped nodules or diffuse enlargement, sometimes accompanied by enlarged nipples and areolas. Localized discomfort or tenderness may be felt, and in a few patients, a small amount of white discharge is seen when the nipple is squeezed. In the case of pathological gynecomastia caused by organic diseases, there should be clinical manifestations of the original disease. (1) Gonadotropin measurement, gonadotropin measurement helps to diagnose whether there is primary or secondary hypogonadism. (2) Liver and kidney function tests are useful for the diagnosis of liver and kidney failure. (3) Cortisol and ACTH, 17-OHP, and blood and urine cortisol measurements Can evaluate congenital adrenal cortical hyperplasia. (1) Breast ultrasound and mammography can differentiate between fat and breast tissue to exclude breast cancer in time. (2) Histopathological examination of breast to further confirm the diagnosis. Treatment 1. 200mg of dihydrotestosterone enanthate, injected intramuscularly once every 3-4 weeks. 2.Tamoxifen (triamcinolone) can bind to estrogen receptors in target tissues and block the effect of estrogen. 3. The mechanism of action of clomiphene is similar to that of tamoxifen (triamcinolone acetonide). 4.Testosterone lactone inhibits aromatase and blocks the conversion of testosterone to E2 in the periphery. 5.Mastoplasty is still an important treatment for this disease due to the irreversibility of the long-term delay of mastopexy in men.