Abstract:
FLT3-ITD mutations are the most common activating mutations in FLT3 gene that occur in about 12 to 38% of acute promyelocytic leukemia cases, and are mainly associated with high white blood cell counts and poor clinical outcome. We present here a case of short isoform [bcr3] of PML-RARα and FLT3-ITD who presented with adverse prognostic features characteristic of variant APL in the form of leukocytosis, hypogranular morphology, and unique immunophenotype. The patient received ATRA and ATO plus IDA instead of standard treatment protocol, and achieved a complete morphological, cytogenetic and molecular response. However, she experienced differentiation syndrome and coagulopathy that was subsequently resolved by appropriate management. The use of FLT3 inhibitor in APL induction management could prevent differentiation syndrome and coagulopathy in patients with FLT3-ITD.
Keywords: Acute promyelocytic leukemia, PML-RARα isoforms, Quantitative polymerase chain reaction ATRA-ATO plus IDA, FLT3-ITD, APL variant morphology and immunophenotype