NCIt definition : A group of malignant mast cell disorders including aggressive systemic mastocytosis,
mast cell leukemia, mast cell sarcoma, and systemic mastocytosis with an associated
myeloid neoplasm. Individuals with advanced systemic mastocytosis have a reduced life
expectancy, with median survival measured in months to years.;
Alternative definition : CDISC: A malignant neoplasm composed of mast cells.;