Acute myeloid leukemia with myelodysplasia-related changes and blasts of the mixed T/myeloid phenotype: a case report

A rare but clinically important diagnostic dilemma arises when cases meet the criteria for both acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) and mixed phenotype acute leukemia, especially those that evolve from myelodysplastic syndrome. We describe a 56-year-old male patient who presented with cytopenias and was initially diagnosed with myelodysplastic syndrome with single lineage dysplasia. Nearly 1 year later, this patient progressed to acute leukemia, and his blast cells simultaneously expressed T-lymphoid and myeloid antigens. Cytogenetic analysis showed a 20q deletion, and next-generation sequencing showed mutations of ASXL1, NRAS, PHF6, RUNX1, TP53, and PIGA. He was diagnosed with AML-MRC with blasts of the mixed T/myeloid phenotype according to the latest World Health Organization guidelines. In accordance with the treatment principles of AML-MRC, we chose an AML-like regimen for four cycles, but the patient did not achieve remission. Finally, we adhered to the treatment principles of mixed phenotype acute leukemia, and he achieved remission after a course of ALL-like regimen chemotherapy.

Automated summary

This case report describes a rare diagnostic dilemma of mixed phenotype acute leukemia and acute myeloid leukemia with myelodysplasia-related changes (AML-MRC). The patient was initially diagnosed with myelodysplastic syndrome but progressed to acute leukemia with blast cells expressing both T-lymphoid and myeloid antigens. Cytogenetic analysis and next-generation sequencing confirmed the diagnosis of AML-MRC with the mixed T/myeloid phenotype. After several cycles of treatment, remission was achieved using an ALL-like regimen.