Langerhans' Cell Histiocytosis
Key points
- Langerhans' cell histiocytosis is a rare disorder characterized by abnormal accumulations of a certain type of cells, called Langerhans' cells, in the bones, skin, lungs and other organs.
- Less common symptoms include fever, weight loss, irritability and "failure to thrive" (inability to maintain weight and fitness).
- Because Langerhans' cell histiocytosis is rare and tends to produce symptoms that could be caused by more common medical problems, this disease often is difficult to diagnose, and diagnosis can take time.
- How long Langerhans' cell histiocytosis will last is hard to predict.
What Is It?
Langerhans' cell histiocytosis is a rare disorder characterized by abnormal accumulations of a certain type of cells, called Langerhans' cells, in the bones, skin, lungs and other organs. Langerhans' cells are a form of histiocyte, a type of white blood cell that is active in the immune system. Normally, Langerhans' cells play an important role in the body's immune defenses, and can be found in the skin, lymph nodes, spleen, bone marrow and lungs. Langerhans' cell histiocytosis formerly was known ashistiocytosis X and includes disorders previously considered separate diseases, including diffuse reticuloendotheliosis, eosinophilic granuloma, Hand-Schuller-Christian disease and Letterer-Siwe disease.
In Langerhans' cell histiocytosis, Langerhans' cells multiply abnormally. Instead of helping to protect the body, these cells in massive numbers cause tissue injury and destruction, especially in the bones, lungs and liver. Although this overgrowth of Langerhans' cells may resemble cancer, most researchers do not consider Langerhans' cell histiocytosis to be a form of cancer. In fact, the Langerhans' cells appear to be normal. There are just too many of them, and they damage tissues where they have accumulated.
The cause of Langerhans' cell histiocytosis is unknown. However, researchers are examining the possibility that some common substance in the environment may trigger the disease by stimulating an overreaction of the immune system. One intriguing observation is that almost all people with the disease whose lungs are involved are current or former cigarette smokers. However, even among smokers, this condition is rare, and smoking seems to play no role in the disease when it affects parts of the body outside the lungs.
Langerhans' cell histiocytosis can develop in only one site or organ, or it can involve several different sites and organs. In most cases, Langerhans' cell histiocytosis that affects many body systems occurs in children younger than 2, whereas single-site disease may occur in people of any age. Langerhans' cell histiocytosis is rare, affecting one in 250,000 children and one in 1 million adults in the United States. Although Langerhans' cell histiocytosis can strike at any age, it is most common in children and young adults, with about 70 percent of cases occurring before age 17. During childhood, Langerhans' cell histiocytosis peaks between the ages of 1 and 3.
Symptoms
Symptoms can include:
- Persistent pain and swelling on a bone, especially in an arm or leg
- A bone fracture, especially one that happens without any apparent trauma or after only a minor injury
- Loose teeth, if Langerhans' cell histiocytosis affects the jaw bones
- Ear infection or a discharge from the ear, if Langerhans' cell histiocytosis affects skull bones near the ear
Written and revised by
Andrey Nailor, M.D.
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