The specific treatment of hard lumps under the breast in boys is as follows: 1. The subcutaneous lymph nodes are swollen, and the lymph nodes are more likely to swell up painfully when they are stimulated. If it is a simple inflammation and not serious, it only needs to be treated with infusion. If it is cancer metastasis causing swollen subcutaneous lymph nodes, this is very serious and needs to be treated in hospital immediately. In the early stage of cancer, surgery is performed to remove it, but in the late stage, only chemotherapy can be administered.2. Breast enlargement is caused by the feminization of male breasts and breast enlargement due to the use of estrogen or the poor function of liver to inactivate estrogen in boys, which is not very serious. If it is a viral hepatitis, it needs to be treated with antiviral drugs.3. Breast cancer, both boys and girls can get breast cancer, the appearance of cancerous nodules indicates a serious condition and requires immediate hospitalization. In the early stage, you can have surgery to remove the breast plus chemotherapy, but in the late stage, you can only have chemotherapy.