KIT‐Negative Systemic Mastocytosis Associated With Acute Myeloid Leukemia

Systemic mastocytosis (SM) is a rare blood disorder characterized by the clonal proliferation of mast cells in tissues. Mast cells release various vasoactive mediators, including histamine, leukotrienes, prostaglandins, platelet-activating factors, and cytokines such as tumor necrosis factor. Clinical manifestations can range from mild itching to severe distributive shock. In some rare cases, mastocytosis is associated with other blood disorders, such as systemic mastocytosis with associated hematologic neoplasm (SM-AHN). Almost all cases of SM exhibit a KIT point mutation. We report a rare case of KIT-negative SM associated with acute myeloid leukemia. Historically, AML has been associated with a poor prognosis, and further research is needed to understand the prognosis of SM associated with AML. In this particular case, the patient underwent induction chemotherapy with azacitidine and venetoclax, and a follow-up bone marrow biopsy showed a reduction in mastocytosis without complete hematologic recovery. The authors aim to present this case as an example of the complex nature of SM and its diverse clinical presentations.