Bone Marrow Features in Patients With Acute Myeloid Leukemia Treated With Novel Targeted Isocitrate Dehydrogenase 1/2 Inhibitors.

This case report aimed to review the bone marrow features of patients with acute myeloid leukemia (AML) treated with isocitrate dehydrogenase 1/2 () inhibitors. Five patients with AML treated with an inhibitor were identified and retrospectively reviewed. We described the morphologic and immunophenotypic findings in the bone marrow, as well as ancillary study results. Two patients showed a hypercellular bone marrow with morphologic and immunophenotypic differentiation of blasts. The bone marrow of one patient displayed a hypoplastic phase. Four of the five patients demonstrated unusual morphologic and/or immunophenotypic populations, including basophilia with mild alterations on the myeloid blasts, a small subset of blasts with expression of T-cell markers not seen in the original immunophenotype, a cluster of differentiation 117 (CD117)-positive progenitor population with erythroid differentiation, and another population reminiscent of erythroid differentiation. Unusual morphologic and immunophenotypic populations can be seen in the bone marrows of patients treated with inhibitors in the presence or absence of definite residual disease. The significance of these populations is uncertain, but further studies could be helpful to understand the meaning of these findings.