Axillary lymphoid hyperechoicity can be caused by lymphadenitis, lymph node metastasis, lymphoma and other diseases. 1. Lymphadenitis: when upper limb infection or chest infection occurs, the infection can involve the axilla, which can cause axillary lymphadenitis and axillary lymph node enlargement, which can be manifested as hypoechoic nodules. 2. Lymph node metastasis: when malignant tumor such as breast cancer occurs, the cancer cells can be transferred to the axilla, and axillary lymph node metastasis will appear, which will manifest as hypoechoic nodes. 3. Lymphoma: Lymphoma is a malignant tumor of blood system, which can appear in many places with enlarged lymph nodes, commonly in neck, supraclavicular and axillary area, etc. Lymphoma can also invade axillary lymph nodes, which can appear locally with enlarged lymph nodes, which can be manifested as hypoechoic nodules. When there are multiple hypoechoic lymph nodes in the axilla, it is important to consult a doctor in a timely manner and take appropriate treatment under the guidance of a specialized doctor, which will help to alleviate the uncomfortable symptoms as soon as possible.