A small hard lump in the armpit is most commonly a benign disease, that is, lipoma or paratesticular breast, which is not serious and can be followed up and observed on a regular basis. Avoid strenuous activities, so as not to cause local soft tissue injury or strain, need to regularly conduct local color ultrasound examination, if the lesion gradually increased or affect the aesthetic appearance, as well as the emergence of pain, you can choose the method of surgical excision, usually under local anesthesia can be operated. Some cases are caused by the enlargement of axillary lymph nodes, especially malignant tumors, the most common is from the breast tissue, will also be manifested as a lump in the breast, this case is very serious in comparison, should further improve the relevant examination, the deadline for surgical treatment. Malignant tumors of the breast are prone to axillary lymph node metastasis, and chemotherapy is necessary after surgery.