The cause of breast cancer in men is unknown, but it may be related to factors such as genetics and testicular hypoplasia. Breast cancer is a malignant tumor that is usually more common in women than in men. The cause of breast cancer in boys is not yet fully understood, but it may be related to a history of breast cancer in the immediate family, hypogonadism or underdevelopment of the testes, and long-term exposure to harmful chemical substances. Some men should also be alert to the fact that breast cancer is induced by over-nutrition, obesity, excessive alcohol consumption and other factors. In addition, long-term application of exogenous estrogen, liver dysfunction, etc., can also increase the chance of breast cancer in boys, and need to pay attention. When boys are diagnosed with breast cancer, common symptoms include lumps in the breast and enlarged local lymph nodes. When boys are diagnosed with breast cancer, they should pay attention to adjusting their mindset and actively cooperate with doctors in order to control their condition and improve their quality of life.