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