Mastocytosis, Systemic

**Definition:** A group of disorders caused by the abnormal proliferation of MAST CELLS in a variety of extracutaneous tissues including bone marrow, liver, spleen, lymph nodes, and gastrointestinal tract. Systemic mastocytosis is commonly seen in adults. These diseases are categorized on the basis of clinical features, pathologic findings, and prognosis.

**Tree numbers:** - C04.557.450.565.465.750 - C20.762.750.750

**Synonyms:** - Systemic Mast-Cell Disease