User:Mr. Ibrahem/Chronic multifocal Langerhans cell histiocytosis

Chronic multifocal Langerhans cell histiocytosis, formally known as Hand-Schüller-Christian syndrome, is a type of Langerhans cell histiocytosis (LCH), which can affect multiple organs. Its three main features are bulging eyes, breakdown of areas of bone (often in the skull), and diabetes insipidus (excessive thirst and dilute urine). However, around 75% of cases do not have all three features. Other features may include an asymmetrical face, ear infections, and advanced gum disease.

It is due to a genetic mutation in the MAPKinase pathway that occurs during early development. The diagnosis may be suspected based on symptoms and MRI and confirmed by tissue biopsy. Blood tests may show low red blood cells, and occationally low white blood cells and low platelets.

Treatment may include some combination of prednisone, vinblastine, cytarabine, and mercaptopurine. The outlook depends on how many and how much organs are affected. In some people the condition is life-threatening. The disease is rare. Most cases occur in the 2 to 6 year old age group. Boys are more commonly affected than girls.

It was previously named after the American pediatrician Alfred Hand Jr., the Austrian neuroradiologist Arthur Schüller, and the American pathologist Henry Asbury Christian, who described it in 1893, 1915 and 1919, respectively. Before the Histiocyte Society classified histiocytoses in the 1980s, LCH was known as "histiocytosis X", where "X" denoted the unknown cause at the time.