Doc: Prognosis for rare disease depends on its extent
Dear Dr. Roach: I have a friend who is the primary caregiver to her son, diagnosed with Langerhans cell histiocytosis. I am unfamiliar with this condition and would like to better understand the challenges and prognosis.
Can you help?
Dear O.C.: Langerhans cell histiocytosis is a rare disease that is difficult to understand. Expert opinion is mixed on whether it is, strictly speaking, a cancer. It acts like cancer in many ways and probably is caused by immune system dysfunction.
The predominant issue is that a type of cell, called a histiocyte, is usually present in bone lesions and can infiltrate other organs, especially the skin, lymph nodes and lungs. The histiocyte seems to be a cell that is derived from bone marrow, and not the Langerhans skin cell it resembles.
LCH is a rare disease, but one that probably is underreported due to misdiagnosis. It most commonly occurs in children ages 1-3.
Treatment depends on how extensive the disease is, so a careful and thorough evaluation is mandatory. In disease limited to the bone or a single lymph node, surgical treatment may be possible.
However, in people with disease in multiple organs or in places not amenable to surgery, treatment is usually with combination chemotherapy. Those with a particular gene mutation may benefit from a medicine used for treatment of melanoma.
Prognosis depends greatly on the extent of the disease. For those with limited disease, the prognosis is very good, with greater than 95 percent survival at five years.
For those with higher-risk disease, especially those with disease in the liver, spleen, or bone marrow, the five-year survival rate was 84 percent in a recent trial.
Those with multisystem disease should consider being in a clinical trial (information at histiocytesociety.org). More information is available at histio.org.
Email questions to ToYourGoodHealth@med.cornell.edu.