What is the definition or description of: mastocytosis?

Too many mast cells: Mastocytosis is a condition in which the body produces too many mast cells. These overgrown mast cells can be confined to the skin (cutaneous mastocytosis), or can be located in the bone marrow and throughout the body (systemic mastocytosis). Symptoms of these disorders vary by location and type, but are thought to be caused by the release of chemical mediators like histamine from the mast cells.