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Maurie Markman, MD, President, Medicine & Science
This page was updated on June 13, 2022.
Castleman disease (CD) is a rare condition that affects the lymph nodes and related tissues. It’s not considered cancer but may act like cancer, and it may develop into lymphoma. While Castleman disease has a wide range of symptoms, the primary sign is enlarged lymph nodes that share a similar appearance when viewed under a microscope.
A healthy immune system involves a network of cells and inflammatory messengers (chemokines and cytokines) that signal for the body to fight disease. The immune cells reside in the lymph nodes.
In patients with Castleman disease, these cells may become overactive and produce too many messengers, particularly Interleukin-6 (IL-6). Too much IL-6 may lead to flu-like symptoms such as fatigue, night sweats, nausea and weight loss, lymph node enlargement, and issues with vital organs, including the liver, kidneys and bone marrow. Problems with these internal organs may lead to fluid gain, confusion, bruising and bleeding.
Named for the Massachusetts General Hospital pathologist who discovered it in 1957, Castleman disease also goes by other names, including:
There are two subtypes:
MCD is more likely to occur in patients who test positive for the human immunodeficiency virus (HIV-positive). Despite success with antiviral medications, they haven’t protected people with HIV from MCD.
MCD is further classified depending on whether the human herpesvirus type 8 (HHV-8) is present. The majority fall into this category, and those that don’t are called idiopathic (or cause unknown) multicentric Castleman disease, or iMCD.
Studies estimate there may be 4,300 to 5,100 new cases of CD each year, according to the American Cancer Society. It may affect men and women at any age, but younger patients tend to have localized CD.
While symptoms vary from person to person, it’s common to experience:
Because Castleman disease is so rare, it’s been hard to study, and questions remain.
The exact cause of Castleman disease isn’t known, and there are no known risk factors. Factors such as viruses, genetic mutations acquired over the course of life, an inherited genetic mutation, autoimmunity and inflammation may contribute to the disease.
Recent research suggests that acquired genetic mutations seem to be the main cause of UCD, and some scientists theorize that an increased production of IL-6 by the immune system may contribute to the disease by causing an overgrowth of lymphatic cells, leading to many of the flu-like signs and other symptoms of CD.
The HHV-8 present in many patients with MCD is also found in nearly all people who are HIV-positive. HIV weakens the immune system’s ability to control the HHV-8 infection, and it’s thought that HHV-8 then causes MCD by making its own IL-6 and an overabundance of lymphatic cells. There are other people with MCD who aren’t HIV-positive but have HHV-8 present, and still others who don’t have either disease.
Most UCD patients don’t experience whole-body symptoms, and many times the enlarged lymph nodes are discovered by accident, during a doctor visit for another condition. A diagnosis typically involves imaging tests such as a computed tomography (CT) scan, ultrasound or magnetic resonance imaging (MRI), as well as a biopsy, which is sent to a lab for evaluation.
While there’s no set diagnostic criteria for MCD, it’s usually diagnosed if a patient has:
A biopsy is essential to make the right diagnosis because the lymph node features found in Castleman disease may also be seen in other diseases, including cancers like lymphoma and autoimmune diseases such as lupus and rheumatoid arthritis.
Treatment depends on the disease type, the severity of symptoms, and whether the patient also has HHV-8 and/or HIV. For example, with UCD, doctors may recommend:
Researchers are looking at several targeted drug therapies developed for other conditions that may work well against MCD. The drugs have the potential to block and neutralize IL-6.