Non-Hodgkin lymphoma

Non-Hodgkin lymphoma (NHL), also known as Non-Hodgkin's lymphoma, is a blood cancer that originate in lymphocytes, part of the immune system. Lymphocytes are found in lymph glands, the spleen and bone marrow. Lymphomas are subdivided into Hodgkin and Non-Hodgkin based on cell morphology. Because lymph glands are found throughout the body and in the brain, NHL can start anywhere.

Causes
Various infectious agents have been associated with (NHL), including Epstein-Barr virus.

Chronic fatigue syndrome
A history of chronic fatigue syndrome was associated with an increased risk of certain Non-Hodgkin lymphomas, specifically diffuse large B cell lymphoma, marginal zone lymphoma, and B cell NHL not otherwise specified.