A Pathogenic NRAS c.38G>A (p.G13D) Mutation in RARA Translocation-negative Acute Promyelocytic-like Leukemia with Concomitant Myelodysplastic Syndrome.

An acute promyelocytic leukemia (APL) patient not demonstrating the retinoic acid receptor α (RARA) translocation is rare. A 76-year-old man was diagnosed with myelodysplastic syndrome (MDS). After a year, abnormal promyelocytes were detected with pancytopenia and disseminated intravascular coagulopathy. Morphologically, the patient was diagnosed with APL; however, a genetic examination failed to detect RARA translocation. Thereafter, whole-genome sequencing revealed an NRAS missense mutation [c.38G>A (p.G13D)]. This mutation was not detected in posttreatment bone marrow aspirate, despite residual MDS. Few reports are available on similar cases. Furthermore, the NRAS c.38G>A mutation may be a novel pathogenic variant exacerbating RARA translocation-negative acute promyelocytic-like leukemia.