Medical Edge Newspaper Column

Rare Disorder Involves Overgrowth of Lymphatic Cells

May 8, 2009
Dear Mayo Clinic:
My previously healthy 28-year-old son was recently diagnosed with multicentric Castleman disease. Information on this disease is sparse. Any information you can provide would be greatly appreciated.

Answer:
Castleman disease, a rare disorder, affects the lymph nodes. Although the disease acts like cancer in some ways, it's not classified as a cancer. Medically speaking, it's a lymphoproliferative disorder. That means it involves an overgrowth of lymphatic cells, which results in a mass or lump of excess cells. There are two kinds of Castleman disease, and treatment and outlook depend on which type your son has.

The first type is called unicentric Castleman disease. In this form, the disorder is confined to one area of the body. Unicentric Castleman disease typically doesn't cause many symptoms. When they occur, symptoms relate to the local lymph node mass. For example, if the mass of Castleman disease is in the chest cavity, a patient may report cough or shortness of breath. Surgery to remove the mass is standard treatment, and, for most people, no further treatment is needed. If the mass is too large to remove successfully, radiation is an option to destroy the excess tissue.

The second form, multicentric Castleman disease, is more complex and more difficult to treat. Multiple areas of the body are affected. Symptoms may include night sweats, weight loss, a general feeling of discomfort or illness (malaise), and chronic weakness or fatigue. Multicentric Castleman disease can also be associated with autoimmune disorders that occur when the body's immune system mistakenly attacks healthy parts of the body. Autoimmune disorders caused by Castleman may result in kidney disease, skin problems and nerve damage, among others.

Because many areas of the body are affected, surgical removal is not a realistic option for multicentric Castleman disease. Instead, medication is used to relieve the symptoms. Because Castleman disease is rare, it's not as well understood as we'd like, and thus the best treatment for multicentric Castleman has yet to be determined.

Chemotherapy often is used to treat multicentric Castleman disease because it targets cells that reproduce rapidly. But the success of chemotherapy is not consistent. Some people may go into remission, while others may experience little or no relief. Medications used to fight lymphoma and multiple myeloma have also been used to treat Castleman disease, again with varying degrees of effectiveness. Very high doses of chemotherapy coupled with bone marrow stem cell transplant also can be useful in some patients.

Right now, research clinical trials investigating Castleman disease hold the best hope for better treatments. One promising area of research involves medications known as monoclonal antibodies. These man-made antibodies are designed to zero in on specific cells in the body that are not working correctly. One such antibody that may be effective for multicentric Castleman disease works by blocking the activity of interleukin-6 (IL-6), an immune-cell protein suspected of having a role in causing the disease. Another monoclonal antibody that may help is rituximab (Rituxan).

Research has shown that the antibody that blocks interleukin-6 works reasonably well in reducing multicentric Castleman disease symptoms. One drawback, however, is that when a person stops taking the medication, symptoms reappear. To be effective in the long-term, these therapies must be continued indefinitely. Also, they are still in the research stage and not yet available to the general public.

Multicentric Castleman disease is more common in patients infected with the AIDS virus. Antiviral therapy sometime helps patients with both conditions but not patients with multicentric Castleman disease without the AIDS virus.

At this time, there's no cure for multicentric Castleman disease. I encourage your son to work closely with his doctor to determine the best treatment plan to control his symptoms. It's not uncommon to try several treatment options before finding the right approach when dealing with multicentric Castleman disease. So, if it takes several tries, don't be discouraged.

Quite a bit of research is addressing multicentric Castleman disease. If your son is interested in the latest treatment options under investigation, he should ask the doctor about his eligibility to participate in research clinical trials.

— Angela Dispenzieri, M.D., Hematology, Mayo Clinic, Rochester, Minn.