Castleman disease

Castleman disease is the name for a group of rare disorders in which lymph nodes become enlarged because of abnormal, excessive growth of lymphoid tissue, often accompanied by fever, fatigue, and abnormal blood test results caused by an overproduction of inflammatory proteins called cytokines. The American pathologist Benjamin Castleman first described the condition in a 1956 case series. Physicians now recognize several distinct forms: unicentric Castleman disease affects a single group of lymph nodes and appears to arise from a localized genetic change in that tissue; multicentric Castleman disease affects lymph nodes throughout the body and is more often linked to infection with human herpesvirus 8, particularly in people with weakened immune systems; and a form called idiopathic multicentric Castleman disease has no identified infectious cause. Despite the viral association in some cases, the disease itself does not spread from person to person. Researchers still debate whether it belongs among the autoimmune diseases, the cancers, or the infectious diseases, since it shares features of all three. Roughly four to five thousand new cases are diagnosed each year in the United States.