Langerhans cell histiocytosis (LCH) is a disorder that primarily affects children, but is also found in adults of all ages. People with LCH produce too many Langerhans cells or histiocytes, a form of white blood cell found in healthy people that is supposed to protect the body from infection. In people with LCH, these cells multiply excessively and build up in certain areas of the body, causing tumors called granulomas to form. The symptoms of LCH vary from person to person, depending on the areas of the body affected. LCH may be found in many areas of the body, including but not limited to the skin and nails, mouth, bones, lymph nodes, pituitary gland, and thyroid gland. When it is found in multiple areas of the body, it is known as multisystem disease. The cause of this disease is unknown, although most data suggest that it is characterized by a growth of immature Langerhans cells that appear to have mutations of the BRAF gene in about half the cases. LCH is not caused by a known infection, is not contagious, nor is it believed to be inherited. There remain differing opinions among experts as to whether it is definitively a cancer or not. Treatment for LCH varies and may include surgery, chemotherapy, radiation therapy, and use of certain medications.
LHC includes four variants, with different degrees of severity:
Because all the variants have many common symptoms it is thought that they may be manifestations of LCH and not separate syndromes.
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