Lymphoma in the armpit is also known as lymphoma in the armpit. Lymphoma is a malignant tumor of the human immune system, often with painless superficial lymph node enlargement as the first symptom, mainly manifesting as swollen lymph nodes in the neck, armpit, groin, and supraclavicular area. In case of subaxillary lymphoma, the first treatment is to have a lymph node biopsy to determine the pathological type of lymphoma, and to improve various examinations, including PET-CT, abdominal ultrasound and bone marrow aspiration, to determine the stage of lymphoma. Different treatments will be given according to the pathological examination and stage. If Hodgkin’s lymphoma is in the early stage, radiation therapy alone can be given; if it is in the middle or late stage, chemotherapy with ABVD regimen can be given; if it is non-Hodgkin’s lymphoma, the preferred treatment is chemotherapy, and the commonly used regimen includes CHOP regimen. In addition, for suitable young patients, autologous hematopoietic stem cell transplantation can be done.