Differentiation syndrome in non-M3 acute myeloid leukemia treated with the retinoid X receptor agonist bexarotene

Differentiation Syndrome, also known as all-trans retinoic acid (ATRA) syndrome, is a well-described clinical phenomenon occurring in patients with the M3 subtype of acute myeloid leukemia receiving ATRA chemotherapy. Bexarotene is a novel synthetic compound that selectively binds and activates retinoic X receptors, a subclass of retinoid receptors not targeted by ATRA. We report a patient with refractory non-M3 acute promyelocytic leukemia (AML) who developed differentiation syndrome during bexarotene monotherapy. This case emphasizes the importance of monitoring for differentiation syndrome among patients receiving retinoid therapies and demonstrates the ability of bexarotene to stimulate differentiation of leukemic blasts.