There are four stages of diffuse large B-cell lymphoma. Stage I is invasion of a single lymph node area or lymph-like tissue, stage II is invasion of two or more lymph node areas on one side of the diaphragm, stage III is invasion of lymph node areas or lymphatic tissue on both sides of the diaphragm, and stage IV is invasion of sites other than lymph nodes. Diffuse large B-cell lymphoma staging should also indicate the presence or absence of B symptoms, which are unexplained fever >38°C, night sweats for more than 3 consecutive days, and unexplained weight loss of 10% within 6 months. The presence or absence of large masses and invasion of extra-nodal organs should also be indicated when staging lymphoma.