Paroxysmal nocturnal hemoglobinuria clone in a patient with acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is a unique subtype of acute myeloid leukemia (AML), which presents with a distinct coagulopathy. Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia which is clonal in nature due to somatic mutation. PNH may evolve to aplastic anemia, and more rarely, to a myelodysplastic syndrome or to AML. The literature review showed that AML is derived from the PNH clone as the leukemic cells lack the expression of glycosylphosphatidylinositol-linked proteins and PNH phenotype disappeared with the onset of acute leukemia. Herein, we report an unusual presentation of the coexistence of two clonal disorders PNH and APL. Our case contributes to the literature that AML in the setting of PNH is a separate disorder.