Castleman Disease

Overview

Castleman disease is a rare condition in which lymph nodes, the small immune glands found throughout the body, grow abnormally large. It is caused by an overactive immune response in which certain immune cells multiply too much. Although it is not a cancer, it shares some features with lymphoma and is sometimes managed by cancer specialists.

There are two main forms. Unicentric Castleman disease affects lymph nodes in a single region and is often cured by surgery. Multicentric Castleman disease affects lymph nodes in many parts of the body, can cause widespread symptoms, and needs ongoing treatment.

Because Castleman disease is rare and its symptoms overlap with infections, autoimmune conditions, and cancers, it can take time to reach the correct diagnosis. Care is usually guided by specialists in blood disorders or cancer, even though the disease is not a cancer itself. The outlook varies widely depending on the form and how the body responds to treatment, so management is tailored to each person.

Symptoms

Symptoms depend on the form. Unicentric disease often causes few or no symptoms and may be found by chance. Multicentric disease tends to cause body-wide symptoms, including:

• Enlarged, sometimes tender lymph nodes in the neck, groin, armpits, or abdomen
• Fever, night sweats, and fatigue
• Unintended weight loss
• An enlarged liver or spleen
• Feeling generally unwell

Blood tests may show anemia or signs of inflammation. Because these symptoms are general, the condition can be mistaken for an infection or other illness at first, and it may take several rounds of testing before the true cause becomes clear.

Causes

The cause depends on the type. Some cases of multicentric Castleman disease are linked to infection with human herpesvirus 8 (HHV-8), especially in people with weakened immune systems. In other cases, no virus is found and the cause is unknown; this is sometimes called idiopathic multicentric Castleman disease.

In many forms, a signaling protein called interleukin-6 (IL-6) is overproduced, driving the immune cells to multiply and causing inflammation throughout the body. The exact reason this happens is not always clear.

Risk Factors

• Infection with human herpesvirus 8 (HHV-8)
• A weakened immune system, such as in people living with HIV

Castleman disease can affect people of any age and either sex. For many people, no clear risk factor is identified, and the condition is not caused by lifestyle or anything a person did.

Diagnosis

Diagnosis requires examining an affected lymph node and ruling out other causes of swelling:

• Lymph node biopsy: Removing and examining a node under a microscope is essential to confirm the diagnosis and tell it apart from lymphoma.
• Blood tests: These check for anemia, inflammation, IL-6 levels, and infections such as HHV-8 and HIV.
• Imaging: CT or PET scans show how many lymph node areas are involved, which helps classify the disease.

Treatment

Treatment depends on the form and severity.

• Surgery: For unicentric disease, removing the affected lymph node is often curative.
• Targeted medicines: Drugs that block IL-6 signaling are a main treatment for multicentric disease and can control symptoms.
• Immune and antiviral therapy: When HHV-8 or HIV is involved, antiviral treatment and therapies that calm the immune system are used.
• Other therapies: Corticosteroids, immune-suppressing drugs, or chemotherapy-type agents may be used in more severe or resistant cases.

Care is usually guided by a specialist, and the plan is tailored to the type of Castleman disease and the person's overall health. Regular follow-up is important, because multicentric disease can flare and may need long-term treatment to keep symptoms and inflammation under control.

When to See a Doctor

See a doctor if you have lymph nodes that stay enlarged for more than a few weeks, especially with fever, night sweats, fatigue, or unexplained weight loss. Seek prompt medical attention for:

• Rapidly growing lymph nodes
• High fever, severe fatigue, or feeling very unwell
• Difficulty breathing or swallowing from enlarged nodes pressing on nearby structures

Persistent swollen lymph nodes always deserve evaluation, since they can have many causes that need different treatments.

Related Topics

Frequently Asked Questions

References

1. National Cancer Institute (NCI). Castleman Disease Treatment.
2. MedlinePlus, U.S. National Library of Medicine. Castleman disease.
3. Genetic and Rare Diseases Information Center (GARD). Castleman disease.
4. National Organization for Rare Disorders (NORD). Castleman Disease.