A 14-year-old boy with a small hard lump under the areola is likely to be gynecomastia, if physiological need not be dealt with, if pathologic need medication or surgical treatment. 1. Physiological: the incidence of pubertal gynecomastia is about 30% to 60%, usually starts at the age of 10 to 12, reaches its peak at the age of 13 to 14, and then completely regresses and recovers at the age of 16 to 17, and less than 5% of pubertal gynecomastia is persistent. Pubertal gynecomastia is caused by a large amount of estrogen synthesized by the testes prior to the secretion of large amounts of testosterone. Most of them can subside on their own and generally do not need treatment. 2. Pathological: mainly due to the imbalance of the ratio of male and female hormones, resulting in abnormal development of gynecomastia and abnormal hyperplasia of the connective tissue of the mammary gland, mostly manifested in the nipple or areola below the appearance of nodular tissue that can be accompanied by tenderness. It can be treated with medication such as oral danazol to inhibit gonadotropin secretion, clomiphene to improve testicular function, and surgery when medication is ineffective. All of the above medications should be used under the supervision of a doctor, and avoid self-medication. 14-year-old boys with small hard lumps under the areola are recommended to consult a specialist for evaluation and treatment.