Histiocytosis is a general name for a group of disorders or "syndromes" that involve an abnormal increase in the number of immune cells that are called histiocytes.
There are three major classes of histiocytosis:
This article focuses only on Langerhans cell histiocytosis (histiocytosis X).
Histiocytosis X has typically been thought of as a cancer-like condition. But more recently, researchers have begun to think it may be an autoimmune disorder. In this type of disorder, a person's immune cells mistakenly attack the body, rather than help the body fight infections. The extra immune cells the body makes may form tumors, which can affect various parts of the body, including the bones, skull, and other areas.
Some forms of the disorder are genetic, which means they are inherited.
Histiocytosis X is thought to affect roughly 1 in 200,000 people each year. It is most often seen in children ages 1 - 15, with the highest rate among children ages 5 - 10.
Pulmonary histiocytosis X is a specific type of histiocytosis X that involves swelling of the small airways and small blood vessels in the lungs. This inflammation leads to lung stiffening and damage. It is most common in 30 - 40 year old adults, usually cigarette smokers. The cause is unknown.
Histiocytosis X often affects the whole body. A disease that affects the whole body is called a “systemic” disorder.
Symptoms can vary between children and adults, but they may have some of the same symptoms. Tumors in weight-bearing bones, such as the legs or spine, may cause the bones to fracture without an obvious reason.
Symptoms in children may include:
Note: Children over 5 years old often have only bone involvement.
Symptoms in adults may include:
The tumors produce a "punched-out" look on a bone x-ray. Specific tests vary depending on the age of the patient.
Tests in children may include:
Tests in adults may include:
Histiocytosis X is sometimes linked to cancer. CT scans and biopsy should be done to rule out possible cancer.
This disorder is treated with corticosteroids, which suppress immune function (including the dangerous cells). Smoking may worsen the response to treatment and should be stopped.
Children may be given other medications depending on their outlook (prognosis). Such medications may include:
Radiation therapy or surgery may also be used to treat bone lesions.
Other treatments may include:
Histiocytosis Association -- www.histio.org
Histiocytosis X affects many organs and can lead to death.
About half of those with pulmonary histiocytosis improve, while others have permanent loss of lung function over time.
In very young patients, the outlook depends on the specific histiocytosis and how severe it is. Some children can live a normal life with minimal disease involvement, while others do poorly. Young children, especially infants, are more likely to have body-wide symptoms that lead to death.
Complications may include:
Children may also develop:
Call your health care provider if you or your child have symptoms of this disorder. Go to the emergency room if shortness of breath or chest pain develop.
Avoid smoking. Quitting smoking can improve the outcome in people with histiocytosis X that affects the lungs.
There is no known prevention for the childhood forms of this disease.
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.