The cause of malignant lymphomas is unknown, although some theories suggest a viral source. Up to 35,000 new cases appear annually in the United States. Malignant lymphomas are two to three times more common in males than in females and occur in all age-groups.

Although rare in children, these lymphomas occur one to three times more often and cause twice as many deaths as Hodgkin’s disease in children under age 15. Incidence rises with age (median age is 50). Malignant lymphomas seem linked to certain races and ethnic groups, with increased incidence in whites and people of Jewish ancestry.