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 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
• Skin rash, usually on the buttocks or scalp
• Swollen glands (enlarged lymph nodes)
• Enlarged liver, with or without signs of liver malfunction, such as jaundice (yellowing of the skin and eyes) and ascites (abnormal accumulation of fluid in the abdomen)
• Bulging eyes, caused by Langerhans’ cell histiocytosis behind the eyes
• Shortness of breath and cough, if the lungs are involved
• Symptoms, such as stunted growth and excessive urination, that are caused by hormone abnormalities

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. Because of this, your doctor may ask questions that are related to those other medical problems, rather than about Langerhans’ cell histiocytosis.

Your doctor will perform a thorough physical examination with special attention to the areas of your body where you are having symptoms. If you have localized bone pain or swelling, your doctor probably will want you to have a series of standard bone X-rays and a bone scan. When it involves the bone, these X-rays may show an area of bone destruction called a lytic lesion, and the bone scan will show “hot spots” where bone is injured and attempting repair. A computed tomography (CT) scan of the spine or pelvis may be recommended if your doctor suspects bone in those areas may be involved. If you have signs of liver disease, your doctor also will order blood tests to help determine how well your liver is functioning. A chest X-ray or a (CT) scan may be recommended if you have lung symptoms or if your doctor suspects your lungs are involved based on the physical examination. A CT scan of the head may be recommended if your doctor suspects your brain may be involved.

If your doctor suspects that you have Langerhans’ cell histiocytosis or if the cause of symptoms remains unknown after preliminary testing, a biopsy may be recommended to establish or confirm the diagnosis. In a biopsy, a small piece of tissue or bone is removed to be examined in a laboratory. In most cases, this biopsy sample will be taken from a part of the body that is affected by the disease, such as a portion of bone, the lung, lymph node or skin. Blood tests will be done to determine whether the bone marrow is involved.

How long Langerhans’ cell histiocytosis will last is hard to predict. In some cases, it disappears gradually without treatment. This is most likely to happen in people who have Langerhans’ cell histiocytosis involving only one area of the body such as the bone or skin, or when a person with lung involvement stops smoking. In other cases, the disease can be fatal, most commonly in people with multisystem disease. For people who smoke, the disease rarely improves while smoking continues.

Because the cause of Langerhans’ cell histiocytosis is not known, there is no way to prevent it. However, since almost all cases involving the lungs develop in people who smoke cigarettes, not smoking may prevent the development of Langerhans’ cell histiocytosis in the lungs.

Treatment depends on the extent of illness:

• Single-system Langerhans’ cell histiocytosis — Highly effective treatments include corticosteroids, such as prednisone (sold under several brand names), with or without chemotherapy, and removing the involved bone area with a scraping procedure called curettage. For isolated skin involvement, a form of chemotherapy (nitrogen mustard) applied directly to the skin may eliminate the disease. Radiation therapy may be recommended if bone involvement produces a weakened area that is likely to fracture. This may occur in the upper leg or spine.
• Multisystem Langerhans’ cell histiocytosis — Chemotherapy may be effective for multisystem Langerhans’ cell histiocytosis though success rates are much lower than with single-system disease. While a number of chemotherapy drugs have been tried, including prednisone, vinblastine (Velban), 6-mercaptopurine (Purinethol) and methotrexate (several brand names).

Call your doctor or your child’s pediatrician if you or your child develops pain or swelling on a bone, a persistent rash or other symptoms of Langerhans’ cell histiocytosis.

Many people with single-system Langerhans’ cell histiocytosis recover completely without recurrence. While many people with multisystem disease respond to chemotherapy, the condition may be fatal in severe or resistant cases.

People with Langerhans’ cell histiocytosis may have a higher-than-average risk of developing cancer later in life, including lymphoma and leukemia The reason for this increased risk is not known.

Diseases and Conditions Center

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.