Non-Hodgkin lymphoma (NHL), also known as non-Hodgkins lymphoma, is a group of blood cancers that includes all types of lymphomas except Hodgkin lymphomas. Symptoms include enlarged lymph nodes, fever, night sweats, weight loss, and tiredness. Other symptoms may include bone pain, chest pain, or itchiness. Some forms are slow-growing while others are fast-growing.Lymphomas are types of cancer that develop from lymphocytes, a type of white blood cell. Risk factors include poor immune function, autoimmune diseases, Helicobacter pylori infection, hepatitis C, obesity, and Epstein–Barr virus infection. The World Health Organization  classifies lymphomas into five major groups, including one for Hodgkin lymphoma. Within the four groups for NHL are over 60 specific types of lymphoma. Diagnosis is by examination of a bone marrow or lymph node biopsy. Medical imaging is done to help with cancer staging.Treatment depends on whether the lymphoma is slow- or fast-growing and if it is in one area or many areas. Treatments may include chemotherapy, radiation, immunotherapy, targeted therapy, stem-cell transplantation, surgery, or watchful waiting. If the blood becomes overly thick due to high numbers of antibodies, plasmapheresis may be used. Radiation and some chemotherapy, however, increase the risk of other cancers, heart disease, or nerve problems over the subsequent decades.In 2015, about 4.3 million people had non-Hodgkin lymphoma, and 231,400 (5.4%) died. In the United States, 2.1% of people are affected at some point in their life. The most common age of diagnosis is between 65 and 75 years old. The five-year survival rate in the United States is 71%.
Signs and symptoms
The signs and symptoms of non-Hodgkin lymphoma vary depending upon its location within the body. Symptoms include enlarged lymph nodes, fever, night sweats, weight loss, and tiredness. Other symptoms may include bone pain, chest pain, or itchiness. Some forms are slow growing, while others are fast growing. Enlarged lymph nodes may cause lumps to be felt under the skin when they are close to the surface of the body. Lymphomas in the skin may also result in lumps, which are commonly itchy, red, or purple. Lymphomas in the brain can cause weakness, seizures, problems with thinking, and personality changes.While an association between non-Hodgkin lymphoma and endometriosis has been described, these associations are tentative. Causes
The many different forms of lymphoma probably have different causes. These possible causes and associations with at least some forms of NHL include:

Infectious agents:
Epstein–Barr virus: associated with Burkitts lymphoma, follicular dendritic cell sarcoma, extranodal NK-T-cell lymphoma and diffuse large B-cell lymphoma. Human T-cell leukemia virus: associated with adult T-cell lymphoma. Helicobacter pylori: associated with gastric lymphoma. HHV-8: associated with primary effusion lymphoma, multicentric Castleman disease. Hepatitis C virus: associated with splenic marginal zone lymphoma, lymphoplasmacytic lymphoma and diffuse large B-cell lymphoma. HIV infection. Some chemicals, like polychlorinated biphenyls (PCBs), diphenylhydantoin, dioxin, and phenoxy herbicides. Medical treatments, like radiation therapy and chemotherapy. Genetic diseases, like Klinefelter syndrome, Chédiak–Higashi syndrome, ataxia–telangiectasia syndrome. Autoimmune diseases, like Sjögren syndrome, celiac disease, rheumatoid arthritis, and systemic lupus erythematosus. Bone trauma and microfractures associated with diffuse large B-cell lymphoma originating in bone marrow.