Lymphoma is a group of blood cancers that develop from lymphocytes (a type of white blood cell). The name often refers to just the cancerous versions rather than all such tumors.Signs and symptoms may include enlarged lymph nodes, fever, drenching sweats, unintended weight loss, itching, and constantly feeling tired. The enlarged lymph nodes are usually painless. The sweats are most common at night.

There are many subtypes of lymphomas.[8] The two main categories of lymphomas are the non-Hodgkin lymphomas (NHL) (90% of cases) and Hodgkin lymphomas (HL) (10%).[9] The World Health Organization (WHO) includes two other categories as types of lymphoma: multiple myeloma and immunoproliferative diseases.[10] About 90% of lymphomas are non-Hodgkin lymphomas.[9][11] Lymphomas and leukemias are a part of the broader group of tumors of the hematopoietic and lymphoid tissues.[12]

Risk factors for Hodgkin lymphoma include infection with Epstein–Barr virus and a history of the disease in the family.[1] Risk factors for common types of non-Hodgkin lymphomas include autoimmune diseases, HIV/AIDS, infection with human T-lymphotropic virus, immunosuppressant medications, and some pesticides.Eating large amounts of red meat and tobacco smoking may also increase the risk.Diagnosis, if enlarged lymph nodes are present, is usually by lymph node biopsy. Blood, urine, and bone marrow testing may also be useful in the diagnosis.Medical imaging may then be done to determine if and where the cancer has spread. Lymphoma most often spreads to the lungs, liver, and brain.

Treatment may involve one or more of the following: chemotherapy, radiation therapy, targeted therapy, and surgery.[1][2] In some non-Hodgkin lymphomas, an increased amount of protein produced by the lymphoma cells causes the blood to become so thick that plasmapheresis is performed to remove the protein. Watchful waiting may be appropriate for certain types.