Favorable outcome of PML‐RARα short isoform and FLT3‐ITD mutation in a patient with several adverse prognostic markers: A case report

Key Clinical Message Complete molecular remission in a “variant APL” patient with short isoform of PML‐RARα and FLT3‐ITD mutation was achieved in response to ATRA and ATO plus IDA instead of standard treatment protocol. The use of FLT3 inhibitor in APL induction management is implicated to prevent differentiation syndrome and coagulopathy experienced in in patients with FLT3‐ITD. FLT3‐ITD mutations are the most common activating mutations in FLT3 gene, occurring in about 12 to 38% of acute promyelocytic leukemia cases, and are mainly associated with high white blood cell counts and poor clinical outcomes. Here, we present a case of APL variant with adverse prognostic features who showed short isoform [bcr3] of PML‐RARα and FLT3‐ITD mutation at diagnosis. The patient received all‐trans retinoic acid (ATRA) and arsenic trioxide (ATO) plus idarubicin (IDA) instead of standard treatment protocol, and achieved a complete morphological, cytogenetic and molecular response. However, the patient experienced differentiation syndrome, and coagulopathy that was subsequently resolved by continuous oxygen therapy, dexamethasone, and enoxaparin. The use of FLT3 inhibitor in APL induction management is implicated to prevent differentiation syndrome and coagulopathy in patients with FLT3‐ITD mutation.