Castleman disease, which is also known as angiofollicular lymph node hyperplasia or giant lymph node hyperplasia, is a very rare disorder of the lymph nodes. Though Castleman's disease does not involve cancerous cells, the symptoms, treatments, and prognosis for patients with Castleman disease are very similar to that of lymphomas.
Definition & Facts
People with Castleman disease suffer from an overgrowth of the lymph node cells that are part of the body's defense system against disease. Though lymph node cells are normally beneficial, the excessive proliferation of cells that people with Castleman disease have can be very problematic.
Castleman disease is typically divided into two categories, localized and multicentric. As the names imply, localized Castleman disease only affects one specific group of lymph nodes, while multicentric can affect lymph nodes and lymphoid tissues throughout the body. These overgrown cells are not technically cancerous, but they behave in a similar way as cancer, and people with Castleman disease often end up developing lymphoma eventually.
Symptoms & Complaints
If the enlarged lymph node is pressing against the lungs or trachea, it can cause difficulty breathing, and if it is pressing against the stomach, it can make a person feel constantly full. Occasionally, people with the localised version of this condition may unexpectedly lose weight, have fevers, night sweats, and feelings of weakness.
When the Castleman disease is multicentric, people will have a wide range of symptoms that are more obvious. Symptoms of multicentric Castleman disease include appetite loss, weight loss, fever, night sweats, fatigue, enlarged lymph nodes, skin rashes, numb hands or feet, and an enlarged liver or enlarged spleen. All types of Castleman disease typically include enlarged lymph nodes, chest pressure and stomach pressure, and exhaustion.
Castleman disease is caused by an overgrowth of B cell lymphocytes, but medical researchers still are not entirely certain of what causes this issue. Multicentric Castleman disease is linked to excessive levels of interleukin 6, a form of protein used to create lymphocytes, but the cause of the high interleukin-6 levels is also unknown.
There is a strong link between Castleman disease and human herpesvirus 8, which also seems to trigger Kaposi's sarcoma. In fact, most people with Castleman disease have been exposed to the human herpesvirus 8 at some point. This virus makes immune system cells malfunction, so they began to overproduce.
In general, people who have a weakened immune system are more likely to get Castleman disease. The multicentric form of Castleman disease is particularly common among people with HIV or AIDS, because the weakened immune system of people with HIV is extremely susceptible to Castleman disease.
People with lymphomas or various forms of autoimmune disease also have a higher risk of developing Castleman disease. Though such immune system conditions may not directly cause Castleman disease, they can contribute to its development.
Diagnosis & Tests
Because the first sign of Castleman disease is often enlarged lymph nodes, the first step to diagnosis the condition is a physical examination to look at the consistency and size of the lymph nodes. Symptoms of localized Castleman disease are mild at first, so the enlarged lymph nodes associated with this form of the condition are often incidentally discovered while doctors are busy screening the patient for other conditions.
If the lymph nodes seem to be unusually large, a doctor may order an imaging test like a CT scan to further examine their size. Once the enlarged lymph nodes are examined, doctors will do blood tests to rule out other infectious diseases that could enlarge lymph nodes. These blood tests can occasionally reveal abnormal protein levels that can also indicate Castleman disease.
It is then necessary to do a biopsy of the unusually large lymph node. A biopsy can look at the tissue of the lymph node to see if there are any signs of cancerous cells or if the unusually large size can be attributed to Castleman disease.
Treatment & Therapy
For patients with localized Castleman disease, the best method of treatment is to remove the diseased and damaged lymph node with surgery. This provides the best prognosis, and makes it less likely that the patient will develop lymphoma later on. If the enlarged lymph node is in an area where surgical removal would be dangerous, radiation therapy has been shown to effectively destroy the excessive growth.
People with multicentric Castleman disease normally cannot be treated with surgery, because there are too many enlarged lymph nodes spread throughout the body. Therefore, the primary method of treatment is medication that slows down or stops cell overgrowth. The most effective option is monoclonal antibodies that block interleukin-6 proteins from stimulating lymphocyte growth, and thalidomide is another medicine that does the same thing. However, people with HIV or a human herpesvirus 8 infection cannot take these antibodies without risking dangerous side effects.
For people who do not respond to interleukin-6 blockers or are unable to take these medications, chemotherapy can slow down cell growth. Treating HIV with antiviral drugs can also help to slow down the progression of Castleman disease by dealing with the underlying cause of the condition.
Prevention & Prophylaxis
There is some limited evidence that beginning antiviral treatments as soon as a person is diagnosed with human herpesvirus 8 or HIV can help the person avoid developing Castleman disease later on.