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

## TL;DR

A patient with acute myeloid leukemia and systemic mastocytosis relapsed with leukemia five years after a stem cell transplant, but mastocytosis did not return.

## Contribution

This case highlights differential immune responses to AML and SM following allogeneic stem cell transplantation.

## Key findings

- AML relapsed five years post-transplant, but SM did not recur.
- AML cells may be more susceptible to graft-versus-leukemia effects than mast cells.
- The case emphasizes the complexity of managing SM-AML and the need for improved treatment strategies.

## Abstract

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.