Case report: Experience of a rare case of primary acute mast cell leukemia

Mast cell leukemia (MCL) is a rare and aggressive form of systemic mastocytosis with a poor prognosis. Understanding the different therapeutic responses to corticosteroids in MCL is crucial for improving patient outcomes.

We present a case of a 74-year-old Chinese female with primary acute MCL who exhibited different responses to dexamethasone and methylprednisolone. She was admitted with persistent fever, dyspnea, severe fatigue, and bone pain, alongside splenomegaly and cytopenia. Diagnosis was confirmed through marrow aspirate analysis, chemical staining, flow cytometry, and biopsy, revealing atypical mast cells positive for CD117, CD9, CD81, CD33, CD13, CD4, and partially for CD56, but negative for CD2 and CD25. Next-generation sequencing identified heterozygous mutations in NRAS, DNMT3A, and TP53, with no KIT mutations. Initial treatment included corticosteroids and dasatinib. The patient showed a partial response to dexamethasone but significant improvement with methylprednisolone. Upon reintroduction of dexamethasone, symptoms recurred, which improved again after resuming methylprednisolone. The patient survived for three months post-diagnosis.

This case highlights the potential efficacy of methylprednisolone over dexamethasone in MCL treatment. This case underscores the importance of personalized treatment approaches in MCL, considering the distinct genetic profile and differential therapeutic responses to corticosteroids. Further research is needed to elucidate the mechanisms underlying these responses and to optimize treatment strategies for MCL.