What’s Up Doc column: Rare disease causes tumors, can occur at any age
Columns share an author’s personal perspective.
Q: What is Langerhans histiocytosis disease?
A: Langerhans cell histiocytosis (LCH), sometimes called histiocytosis X, is a rare cancer (or maybe more accurately a “cancerlike” condition, as some researchers note it also seems to have some properties of an autoimmune condition) where histiocytes (a type of immune cell found in the bone marrow, bloodstream, skin, liver, lungs, lymph glands and spleen that helps destroy foreign materials and fight infection) begin to over-multiply and form tumors (an abnormal mass of tissue). It is not an infectious condition and does not appear to be genetic (it does not seem to run in families). Langerhans histiocytes are specifically found in the skin, mucous membranes and certain other locations. Although this condition can occur at any age and in anyone, it is more common in males than females, and most commonly presents in childhood between the ages of 1 and 3. It is diagnosed in about 1 per 200,000 Americans per year.
LCH can occur in bone (the most common presentation, occurring in three-quarters of LCH patients and possibly causing pain and affecting function; the skull is the most common bone involved in kids), can cause certain types of rash (skin is affected in about 40% of patients), and less commonly (in 5-20% of patients) can affect other organs (ears, eyes, teeth, spleen, liver, central nervous system/CNS, gastrointestinal/GI, others) and their functions (for example causing diabetes insipidus, seizures, headaches, and/or other symptoms from CNS involvement, breathing issues from lung involvement, GI symptoms from liver/GI involvement, other symptoms). It can also cause general non-specific symptoms like weakness, fatigue, fever, swollen glands and other symptoms.
LCH is suspected based on symptoms, and also possibly when a test is ordered (for example an X-ray due to bone pain or limp) and the findings are suggestive of possible LCH. The larger number of organs that can possibly be affected, and the variability in symptoms and presentation, can make the diagnosis a bit tricky in some cases (especially in older patients). Certain blood tests, other imaging tests (depending on the symptoms, X-rays, CT, MRI and/or other tests may be indicated) and finally a biopsy with examination of the tissue under a microscope, may all be indicated to help make the diagnosis. An important part of this workup is to determine the extent/staging of disease.
The staging of the severity of LCH depends on the specific ways the disease affects the specific patient. The first step is to determine if the patient has one organ system involved (for example, is it localized to only bones, only skin, etc.; this single-organ disease presentation is more common in older kids) or multiple organ systems (the more common presentation in kids under age 3). In addition, certain organ system involvement is thought to make the disease higher risk (for example, the hematopoietic system where blood cells are made, liver, spleen and sometimes the lungs are considered higher risk organs).
As this is overall a rare disease, the specific best treatments are not completely elucidated, and hence many patients diagnosed with LCH benefit from enrolment in a clinical trial where state-of-the-art treatments are being evaluated. Depending on the location and extent of disease, treatments may include surgery (to remove the tumor, especially indicated when there is a single-organ system involved and surgery is possible), radiation therapy, and/or chemotherapy, not dissimilar to how many cancers are treated. The specific chemotherapeutic agents used depend on the patient’s specific disease and clinical status, and are one of the factors being evaluated in many of the clinical trials. All LCH patients need to be carefully followed to evaluate for possible progression of disease.
The prognosis of LCH is very variable. In many young children with lower-risk disease (single-organ system involved) the condition may resolve on its own, and/or surgery for the identified tumor may be curative (“curative” here is defined to be no disease recurrence within five years). Many patients with multi-system involvement, and even many with high-risk organ involvement, respond well to treatments (usually chemotherapy for these patients). One website I found from St. Jude’s Children’s Hospital noted that 99% of low-risk LCH patients and 80% of high-risk patients survive at least five years. Complications from the disease and/or treatments (for example, orthopedic complications from the required surgery or from the disease itself) can occur.
Although LCH is an uncommon disease, the present treatments often yield an overall good prognosis, and ongoing studies will hopefully improve on these even more. As with all rare diseases, if you or a loved one are diagnosed with LCH it is a good idea to be treated by specialists with experience and expertise specifically in this rare condition.
Jeff Hersh, Ph.D., M.D., can be reached at DrHersh@juno.com.