Castleman disease

Overview

Castleman disease is a group of rare disorders that involves lymph nodes that get bigger, called enlarged lymph nodes, and a wide range of symptoms. The most common form of the disorder involves a single enlarged lymph node. This lymph node is usually in the chest or neck, but it can occur in other areas of the body as well. This form of the disorder is called unicentric Castleman disease (UCD).

Multicentric Castleman disease (MCD) involves multiple regions of enlarged lymph nodes, inflammatory symptoms and problems with organ function. There are three types of MCD:

• HHV-8-associated MCD. This type is linked to human herpes virus type 8, called HHV-8, and human immunodeficiency virus (HIV).

• Idiopathic MCD. The cause of this type is unknown. This also is called HHV-8-negative MCD.

  The most serious form of this type of MCD is known as iMCD-TAFRO. This condition gets its name from the symptoms it causes.

• POEMS-associated MCD. This type is linked to another condition called POEMS syndrome. POEMS syndrome is a rare blood disorder that damages nerves and affects other parts of the body.

Sometimes, people may have 2-3 enlarged lymph nodes and mild symptoms that do not meet the diagnostic criteria for MCD. These people may have another disease, or they may have the recently described subtype of Castleman disease called oligocentric Castleman disease. This subtype is rare.

Treatment and outlook vary depending on the type of Castleman disease you have. Unicentric Castleman disease, which is the type that involves only one enlarged lymph node, can usually be successfully treated with surgery.

The best treatment for oligocentric Castleman disease, which involves a few enlarged lymph nodes and has limited symptoms, is not known but is thought to be similar to the treatment for unicentric Castleman disease.

While not all people with MCD respond to the first treatment, there are medicines that work to treat HHV-8-associated MCD and idiopathic MCD.

Symptoms

Many people with unicentric Castleman disease don't notice any signs or symptoms. The enlarged lymph node may be found during a physical exam or an imaging test for a different problem.

Some people with unicentric Castleman disease might have signs and symptoms that are more often seen in multicentric Castleman disease. These may include:

Body symptoms

• Fever.
• Weight loss that happens without trying.
• Fatigue.
• Night sweats.
• Swelling.
• Enlarged liver or spleen.

Blood symptoms

• Low red blood cell count, also called anemia.
• High or low platelet counts.
• Higher creatinine levels that happen because the kidneys don't work properly.
• Higher levels of antibodies known as immunoglobulins.
• Low levels of a blood protein called albumin.

Symptoms of the more serious form of idiopathic MCD called iMCD-TAFRO are:

• Low platelet count, also called thrombocytopenia.
• Swelling and fluid in the body, known as anasarca.
• Fever or a higher level of C-reactive protein, a marker of inflammation.
• Reticulin fibrosis, which is checked by taking a sample of bone marrow.
• Organ swelling, also called organomegaly.

When to see a doctor

If you notice an enlarged lymph node on the side of your neck or in your underarm, collarbone or groin area, talk with your healthcare professional. Also call your care team if you have a lasting feeling of fullness in your chest or abdomen, fever, fatigue, or weight loss that you can't explain.

Causes

It's not clear what causes unicentric Castleman disease or idiopathic multicentric Castleman disease (MCD). However, HHV-8-positive MCD is known to occur in people who don't have typical function in their immune systems because of HIV or other causes.

Risk factors

Castleman disease can affect people of any age or gender. People usually are diagnosed with Castleman disease during midlife, but it can happen at any age, including during childhood.

There are no known risk factors for unicentric Castleman disease or idiopathic multicentric Castleman disease. Infection with HIV or having a condition that decreases how well the immune system works raises the risk of having HHV-8-positive multicentric Castleman disease.

Complications

People with unicentric Castleman disease (UCD) usually do well once the affected lymph node is removed, and life expectancy is usually not changed. But they are at increased risk of developing a rare autoimmune condition called paraneoplastic pemphigus. This condition can be life-threatening. Paraneoplastic pemphigus causes blisters in the mouth and on the skin that are often misdiagnosed. Though the risk of developing paraneoplastic pemphigus is low, being checked for this condition is important if you have UCD.

Idiopathic multicentric Castleman disease can rapidly get worse to involve life-threatening problems with organ function. This requires critical care with a machine that helps with breathing, called a ventilator, and treatments that help with organs function, such as dialysis and transfusions.

HHV-8-positive multicentric Castleman disease may involve life-threatening infections and organ failure. People who also have HIV/AIDS generally have worse outcomes.