Gynecomastia is a benign male disease caused by endocrine disorders or other organic diseases. The main clinical symptoms are breast enlargement, swelling and pain, and lumps to palpation, and individual nipple overflow. The etiology and pathogenesis of the disease are not yet clear, but the causes are clear: congenital testicular hypoplasia, testicular atrophy or excision, testicular malignancy, adrenal cortical tumors, acromegaly, chronic liver disease leading to hepatic hypoplasia, traumatic paraplegia, long-term use of estrogen, digitalis, androstenedione, etc. These diseases and drugs cause an increase in the concentration of estrogen in the body. These diseases and drugs cause an increase in the concentration of estrogen in the body and increase the sensitivity of the male breast to estrogen, which in turn leads to hypertrophy of the male breast. In particular, gynecomastia can occur in elderly prostate cancer patients after long-term estrogen treatment. In recent years, foreign studies have shown that male breast development is also locally related to the level of aromatase and estrogen receptor (ER) in the breast tissue. This explains why the majority of male breast development in clinical practice is unilateral, or it may develop unilaterally and then bilaterally only after a few months or years, and rarely both sides develop at the same time. More convincingly, the conservative treatment with the estrogen receptor antagonist triamcinolone has been effective in the recent past, but there is a possibility of recurrence after discontinuation of the drug. The cause is not clear: it may be related to pubertal development and endocrine disorders, or it may be related to dietary structure and environmental factors. The diagnosis of gynecomastia is usually seen during the developmental period of spring and youth and in old age with physiological radical changes, mostly with swelling and pain or tenderness, with female-like developmental hypertrophy, mostly unilateral, with smooth, firm, discoid nodules around the nipples, with medium texture, mostly located under the areola, with clear borders, without adhesion to the skin and pectoral muscles, with nodular masses under the areola, with vague pain or mild tenderness in a few patients. The diagnosis can be made after excluding obesity, submammary adipose tissue hyperplasia, nutritional mastopathy and male breast cancer. The histological features of the disease include fatty tissue interspersed with hyperplastic fibrous tissue, scattered ductal hyperplasia and cystic dilatation, multi-layered ductal epithelial hyperplasia, and ductal branching without the presence of breast lobules. However, it must be differentiated from male breast cancer and fibroids: breast cancer is more common in elderly patients, and breast lumps are mostly isolated in the upper 1/4 of the body, hard and tough without pressure, irregular in shape, surrounded by short, thin burrs. The lesions often infiltrate peripherally (especially the pectoralis muscle) with limited mobility, may adhere to the skin, or are associated with ipsilateral axillary lymph node enlargement, and generally have marked nipple depression. The latter is more clearly defined, with smoother margins and greater mobility, and sometimes a thin, transparent halo lined by fat can be seen. At present, mammography is an important measure to detect gynecomastia earlier and more accurately than clinical examination: if the diagnosis is unknown, it is better to do biopsy X-ray main manifestations are: (1) dense lamellar shadow centered on the areola, the most common, X-ray mainly shows triangular and conical lamellar dense shadow in the subareolar area, some are accompanied by brush-like or dendritic protrusion shadow, diffuse downward and reach into the surrounding (2) Nodular swelling (2) Nodular masses, which appear as round or ovoid dense masses of approximately uniform density centered on the areola, may have superficial lobulation. Treatment The treatment should be individualized according to the cause of the disease, and psychological barriers should be eliminated. For masses <3 cm in diameter, conservative treatment should be used; for those with a definite cause, etiologic treatment should be provided. Among the hormone therapy, triamcinolone acetonide is more effective. As long as the cause is removed, clinical cure can be achieved. For those with lumps of 3-6 cm in diameter, the addition of methyltestosterone and vitamin E to reduce the level of estrogen in the body's blood as soon as possible and block glandular hyperplasia can achieve better results in addition to causative treatment. The effect of testosterone treatment is not good, and there are 4 cases in this group with no obvious effect after testosterone treatment, and finally surgery is used for those with lumps >6cm in diameter and those with poor effect by medication, lump excision with preservation of nipple and areola should be used to maintain the normal appearance of male breast. The indications for surgery are that gynecomastia should be treated surgically in addition to etiologic therapy. If hormone therapy is ineffective or if there is a hard node after the hypertrophy has subsided, or if the patient is under psychological stress or suspected of malignancy, all of these are indications for surgery, and this group uses a curved incision under the areola to preserve the nipple and skin and mastectomy.