Non-Hodgkin lymphoma (NHL) is a type of cancer that originates in the lymphatic system, which is part of the body's immune system. It involves the uncontrolled growth of lymphocytes, a type of white blood cell. NHL can occur in various forms, affecting different types of lymphocytes, and can develop in lymph nodes or other organs. Symptoms of non-Hodgkin lymphoma may include swollen lymph nodes, fever, night sweats, and unexplained weight loss. Diagnosis typically involves blood tests, imaging studies, and a biopsy of affected tissue. Treatment options may include chemotherapy, radiation therapy, and targeted therapies, depending on the specific type and stage of the disease.