Relapse of Acute Myeloid Leukemia With Concomitant Systemic Mastocytosis Five Years Post Allogenic Hematopoietic Stem Cell Transplantation.

Systemic mastocytosis (SM) with associated hematological neoplasia (SM-AHN) is a rare and aggressive condition characterized by abnormal clonal proliferation of mast cells and the concurrent occurrence of hematologic malignancies, such as acute myeloid leukemia (AML). We present a 41-year-old female diagnosed with SM-AML, who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). Despite an initial favorable response to chemotherapy and transplantation, the patient later experienced an AML relapse five years post-transplant, without concurrent recurrence of SM. This discrepancy may be attributed to the differential immune responses to AML and SM, where AML cells are more susceptible to graft-versus-leukemia (GVL) effects, while mast cells in SM may exhibit resistance to immune-mediated elimination. The absence of SM relapse raises important questions regarding the pathophysiology and treatment of SM-AML. This case underscores the complexity of managing SM with AML, highlighting the need for further research to optimize therapeutic strategies and improve patient outcomes.