Castleman disease is a rare disease of the lymph nodes and the related tissues that involves an overgrowth of cells in the lymphatic system. It is also known as giant lymph node hyperplasia, angiofollicular lymph node hyperplasia (AFH) or a lymphoproliferative disorder, which means that there is an abnormal overgrowth of cells of the lymph system. Even though CD is not officially a cancer, one form of this disease (known as multicentric CD) acts very much like lymphoma and many people eventually develop lymphomas. Hence, it is often treated with chemotherapy or radiation therapy.
Symptoms
The main way to classify CD is based on how much of the body it affects and they affect people very differently. The 2 main forms of CD are:
- Localized (unicentric), where only a single gland in the lymphatic system is affected; and
- Multicentric, multiple lymph nodes and lymphatic tissues are affected and can severely weaken the immune system.
Many people with unicentric CD don't notice any signs or symptoms. The diseased lymph node is usually located in the chest, neck or abdomen. When signs and symptoms are present, they may include:
- A feeling of fullness or pressure in the chest or abdomen that can cause difficulty breathing or eating;
- An enlarged lump under the skin in the neck, groin or armpit;
- Unintended weight loss;
- Less commonly, fever, night sweats and weakness.
Most people with multicentric CD experience fever, night sweats, fatigue and weakness, loss of appetite, unintended weight loss, enlarged lymph nodes and enlarged liver or spleen.
Causes
It is not clear what the exact causes of CD are. However, an infection by a virus called human herpesvirus 8 (HHV-8) is associated with the Multicentric type of CD. The precise role of HHV-8 is still unclear, but it appears to cause malfunctioning immune system cells to reproduce rapidly. The immune system cells produce a protein called interleukin-6 that contributes to the overgrowth of lymphatic cells.
Complications
People with Unicentric CD usually do well once the affected lymph node is removed. However, having CD may increase the risk of lymphoma.
The outlook for people with Multicentric CD varies, depending on the nature of their disease. Complications of Multicentric CD can be life-threatening and may include:
- Infection leading to the failure of multiple organs
- Cancer, such as lymphoma or Kaposi's sarcoma
Risk Factors
CD can affect anyone, but the average age of people diagnosed with Unicentric CD is 35. Most people with the Multicentric form are elderly (in their 50s and 60s). The Multicentric form is also slightly more common in men than in women.
