Histiocytosis X

A rare childhood disease in which there is an overgrowth of a type of tissue cell called a histiocyte. The cause is unknown, but histiocytosis X probably results from a disturbance of the immune system. In the mildest form, rapid cell growth occurs in 1 bone only, usually the skull, a clavicle, a rib, or a vertebra, causing swelling and pain. In the most severe, and least common, form, there is a rash and enlargement of the liver, spleen, and lymph nodes.

 

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