What is Castleman disease

Castleman disease is a rare, complex disorder involving the overgrowth of cells within the lymph nodes, which can lead to systemic inflammation and organ dysfunction. Unlike lymphoma, it is not a cancer, but it behaves like a lymphoproliferative disorder that can vary from a localized growth to a life-threatening systemic illness.

What are the main types of Castleman disease?

Clinicians classify Castleman disease based on the number of lymph node regions involved and the presence of human herpesvirus-8 (HHV-8). The two primary clinical classifications are:

• Unicentric Castleman disease (UCD): Affects a single lymph node region and is typically localized. Surgical removal is often curative.


• Multicentric Castleman disease (MCD): Involves multiple lymph node regions and causes systemic symptoms. This form is further divided into HHV-8-associated MCD and Idiopathic Multicentric Castleman disease (iMCD).

How does Castleman disease affect the body?

In Castleman disease, the immune system becomes overactive, leading to an "interleukin-6 (IL-6) storm"—a massive release of inflammatory proteins. This systemic inflammation can damage multiple organ systems, including the liver, kidneys, bone marrow, and lungs. While UCD is often asymptomatic, iMCD patients frequently experience fever, fatigue, weight loss, night sweats, and peripheral edema.

Who is typically affected by Castleman disease?

Castleman disease is exceptionally rare, with an estimated incidence of 1 in 20,000 to 1 in 50,000 people in the United States. It can affect individuals of any age, though UCD is often diagnosed in the 3rd or 4th decade of life, while iMCD often presents in the 5th or 6th decade. There is no specific geographic predilection, and it affects men and women with relatively equal frequency.

What differentiates Castleman disease from other conditions?

Castleman disease is frequently misdiagnosed as lymphoma or autoimmune conditions due to overlapping symptoms like enlarged lymph nodes and inflammation. Key differentiators include:

1. The specific histopathology (microscopic appearance) of the lymph nodes.


2. The absence of malignant clonal cells, distinguishing it from true lymphomas.


3. The specific elevation of inflammatory markers, particularly IL-6, which is a hallmark of the iMCD subtype.

At DiseaseMaps.org, 59 people with Castleman disease have joined our community to share their experiences and navigate these complex diagnostic challenges.

Next steps

• Consult with a hematologist-oncologist who specializes in lymphoproliferative disorders.


• Request a biopsy of the affected lymph node to be reviewed by a pathologist experienced in Castleman disease.


• Join the DiseaseMaps.org community to connect with others currently managing this diagnosis.


• Explore resources from the Castleman Disease Collaborative Network (CDCN) for the latest clinical trial information.

Medical disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment; always seek the advice of your physician regarding a medical condition.

References

• NIH Genetic and Rare Diseases (GARD) Information Center: Castleman Disease.


• Orphanet: Multicentric Castleman disease.


• Castleman Disease Collaborative Network (CDCN): Clinical Guidelines.


• OMIM (Online Mendelian Inheritance in Man): Castleman Disease entry.