Clinicopathological and Immunophenotypic Characteristics of Series of Re-arranged Acute Leukemias.

Rearrangement involving gene (-r) is recently being described in acute leukemias. We present the clinic-pathological and immunophenotypic findings in a series of five cases of acute leukemia with -r reported in our Institute between September 2020 to September 2023. Notably, while fusion was the most frequently encountered abnormality, the fusion partner was not identified in two patients with -r BCP-ALL. Immunophenotypically, patients presenting as B-cell precursor acute lymphoblastic leukemia (BCP-ALL) had a distinct profile characterized by weak or absent CD10 expression and the presence of myeloid markers such as CD13/CD33. Our findings underscore the importance of recognizing the distinct immunophenotypic features of ZNF384-r leukemias, particularly in cases presenting with atypical BCP-ALL or B/Myeloid mixed phenotype acute leukemia phenotypes. Moreover, these findings highlight the necessity for tailored diagnostic algorithms in clinical laboratories to facilitate the timely and accurate diagnosis of this clinically relevant leukemia subtype.