There are two most common possibilities for hard lumps in the armpit: one is the enlargement of the axillary lymph nodes in the armpit; the other is the possibility of the existence of parametrial breast. For swollen axillary lymph nodes, ultrasound examination can be done to clarify the cause of the swollen lymph nodes, if necessary, by surgery or biopsy. There is also the parametrium, which is a congenital formation of the parametrium gland, that is, there is a breast tissue under the armpit in addition to the mammary gland, the symptoms are mainly manifested in swelling and pain with the menstrual cycle, which is similar to the symptoms of mastopexy. If this symptom exists and it affects the aesthetics, it can be treated by surgical removal. If there are no symptoms and it does not affect the appearance, it can be closely observed.