Mastocytosis

**Definition:** A rare neoplastic disorder characterized by a clonal proliferation of MAST CELLS, associated with KIT-D816 mutations, and accompanied by aberrant mast cell activation. The abnormal increase of MAST CELLS may occur in only the skin (MASTOCYTOSIS, CUTANEOUS), in extracutaneous tissues involving multiple organs (MASTOCYTOSIS, SYSTEMIC), or in solid tumors (MASTOCYTOMA).

**Tree numbers:** - C04.557.450.565.465 - C20.762.750