Detection of cytogenetically cryptic PML-RARA fusion in acute promyelocytic leukemia by rapid next generation sequencing

Acute promyelocytic leukemia (APL) is a medical emergency that requires treatment to be initiated as soon as the disease is suspected in order to decrease the risk of early death, which is mostly caused by APL-associated coagulopathy. Currently, the diagnosis of APL relies on the detection of PML-RARA fusion by fluorescence in situ hybridization (FISH). However, rare cases are cytogenetically cryptic, negative by FISH, and require other molecular techniques to detect the fusion. Moreover, next generation sequencing (NGS) has not been incorporated in the routine diagnosis of leukemia-associated fusions. Hereby, we present a clinical APL case, reported negative by FISH, where PML-RARA fusion was detected by next generation sequencing (NGS) within 48 h, indicating the benefit of incorporating rapid NGS into the routine diagnostic management of acute leukemia patients.