Gynecomastia, also known as gynecomastia, is a condition in which one or both of a man’s breasts are enlarged and developed in a female-like manner, sometimes accompanied by a breast-like discharge. In recent years, gynecomastia has been on the rise in clinical practice, with patients coming in on average every day. Because enlarged breasts often affect the patient’s self-esteem, patients have varying degrees of low self-esteem in social life, such as not daring to swim in public, taking off their tops when playing ball, not daring to lift their chests for fear that their breasts or nipples are too visible, etc. The etiology of gynecomastia is related to many endocrine factors. Elevated or relatively elevated estrogen in the blood, or defective androgen receptors, or increased sensitivity of estrogen receptors in the gland to estrogen can lead to various types of gynecomastia. Gynecomastia is clinically classified as primary or secondary. Primary gynecomastia is predominantly seen in adolescent and older patients and often resolves on its own. Secondary gynecomastia can be due to hypogonadism or secondary to systemic diseases, or secondary to tumors, medications, etc. Ultrasound examinations often reveal enlarged breast glands or thickened fat; notably, there are also some patients with pseudogynecomastia who have excess fatty tissue, resulting in pseudogynecomastia without glandular enlargement. This also accounts for a proportion of patients who visit the clinic. In sex hormone tests, a significant proportion of patients have elevated estrogen levels or decreased androgen levels. Treatment is mostly based on etiology, and those who cannot reduce the size of their breasts after removal of the etiology can be treated surgically. Surgery is usually done by fat aspiration plus glandular excision. For enlarged nipples, surgical reduction is also possible with good results.