About langerhans cell histiocytosis

What is langerhans cell histiocytosis?

Langerhans cell histiocytosis (LCH) is a spectrum of rare disorders characterized by overproduction (proliferation) and accumulation of a specific type of white blood cell (histiocyte) in the various tissues and organs of the body (lesions). The lesions may include certain distinctive Langerhans cells involved in certain immune responses, as well as other white blood cells (e.g.,lymphocytes, monocytes, eosinophils). Associated symptoms and findings may vary from case to case, depending upon the specific tissues and organs affected and the extent of involvement. Most often the bone lesions are painful. Skin rashes may itch or cause painful ulcers especially under the arms or groin area. The pathogenesis (medical cause) is not clearly understood and an ongoing debate continues regarding its cause as a reactive immunologic or neoplastic (cancer-like) process. No infectious agent (virus, bacteria, or fungus) has been associated with LCH. Patients often have a strong family history of immune diseases such as thyroid disease, arthritis, or lupus.

Most affected individuals have single or multiple bone lesions characterized by lytic lesions (holes in the bones). Although the skull is most commonly affected, there may also be involvement of other bones, such as those of the spine (vertebrae) and the long bones of the arms and legs. Affected individuals may have no apparent symptoms (asymptomatic), or may experience associated pain and swelling, and/or develop certain complications, such as fractures or secondary compression of the spinal cord. Other organs may also be affected, including the skin, lungs, liver, spleen, bone marrow, thymus, thyroid,intestines and brain. In some individuals, LCH may be associated with involvement of the pituitary gland leading to diabetes insipidus, growth failure, hypothyroidism, or insufficitne production of sex hormones.

Langerhans cell histiocytosis was selected by the Histiocyte Society to replace the older, less specific term histiocytosis X. Histiocytosis X encompassed three entities known as eosinophilic granuloma, Hand-Schuller-Christian disease, and Letterer-Siwe disease that were characterized by the accumulation of histiocytes. The "X" denoted that the cause and development of the disorder was not understood. Langerhans cell histiocytosis was chosen because it seemed that the Langerhans cells might play a central role in the development of these disorders. However, new research (Allen 2010) has shown that the skin Langerhans cell is not the cell of origin, but a myeloid dendritic cell.

What are the symptoms for langerhans cell histiocytosis?

LCH can show up on many places on your body, but most often on your skin and bones. It can affect any organ, including your lungs, liver, brain, spleen, or lymph nodes.

In about 8 out of 10 people, LCH leads to tumors called granulomas in the skull and in other bones. That can cause Pain and swelling, and sometimes it can fracture your arms or legs.

LCH symptoms can range from mild to more serious. Some people are born with it, and the disease eventually goes away on its own. But others have a severe and long-lasting type that affects multiple parts of the body.

What are the causes for langerhans cell histiocytosis?

Somatic mutations in the BRAF gene have been identified in the Langerhans cells of about half of individuals with Langerhans cell histiocytosis. Somatic gene mutations are acquired during a person's lifetime and are present only in certain cells. These changes are not inherited.

The BRAF gene provides instructions for making a protein that is normally switched on and off in response to signals that control cell growth and development. Somatic mutations cause the BRAF protein in affected cells to be continuously active and to transmit messages to the nucleus even in the absence of these chemical signals. The overactive protein may contribute to the development of Langerhans cell histiocytosis by allowing the Langerhans cells to grow and divide uncontrollably.

Changes in other genes have also been identified in the Langerhans cells of some individuals with Langerhans cell histiocytosis. Some researchers believe that additional factors, such as viral infections and environmental toxins, may also influence the development of this complex disorder.

What are the risk factors for langerhans cell histiocytosis?

Langerhans cell histiocytosis is usually not inherited and typically occurs in people with no history of the disorder in their family.

A few families with multiple cases of Langerhans cell histiocytosis have been identified, but the inheritance pattern is unknown.

Is there a cure/medications for langerhans cell histiocytosis?

In many people with Langerhans cell histiocytosis, the disorder eventually goes away with appropriate treatment. It may even disappear on its own, especially if the disease occurs only in the skin. However, some complications of the condition, such as diabetes insipidus or other effects of tissue and organ damage, may be permanent

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