KIT V560D-Mutated Systemic Mastocytosis Associated With High-Risk Myelodysplastic Syndrome: A Unique Case of Systemic Mastocytosis-Associated Hematologic Neoplasm.

Systemic mastocytosis (SM) is a rare hematologic disorder characterized by clonal proliferation of mast cells in the bone marrow and/or other organs. SM-associated hematologic neoplasm (SM-AHN) is one of the advanced SM variants that usually confer a poor prognosis. We present a case of a 75-year-old female patient with SM-AHN, specifically myelodysplastic syndrome (MDS), that harbored a unique KIT mutation KIT V560D, not previously described in the literature in this setting. We describe the clinical course and the outcome with the use of avapritinib, midostaurin, and decitabine-cedazuridine. Trial Registration: ClinicalTrials.gov identifier: NCT00782067.