Acute Non-promyelocytic Leukemia with Complex Karyotype and Novel t (15;17) (q21; p11.2)/B2M: RARA Fusion: A Case Report

Background: The t(15;17)(q22;q21) is a well-known cytogenetic abnormality in acute promyelocytic leukemia (APL) and has defined management and better outcomes compared to other acute myeloid leukemia subtypes. Acute myeloid leukemia (AML) with t(15;17)(q21;p11.2) cytogenetic abnormality and associated B2M::RARA molecular abnormality has not been previously reported. Case Presentation: The patient reported here was a 48-year-old female who presented with generalized weakness, with no lymphadenopathy or organomegaly. Further evaluation for pancytopenia revealed a diagnosis of AML confirmed by immunophenotyping using flow cytometry. Conventional karyotyping revealed a complex karyotype with the presence of 48, XX, add(1)(q44), +der(1), del(3)(q12q21), del(5)(q31), del(6)(q21), t(15;17)(q21;p11.2), +21[cp20]. Fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) for PML-RARA t(15;17)(q24;q21) were negative, and next-generation sequencing (NGS) revealed TP53 mutation and B2M-RARA fusion. The patient was managed with a hypomethylating agent plus venetoclax (VEN) therapy. Conclusion: t(15;17)(q21;p11.2) is a novel cytogenetic abnormality in AML, along with the B2M-RARA fusion, and warrants thorough evaluation to rule out APL.