[Detection of PML/RARA rearrangement by reverse transcriptase-PCR and sequencing in a case of microgranular acute promyelocytic leukemia lacking t(15;17) on karyotype and FISH].

We report a case of morphologically microgranular acute promyelocytic leukemia with PML/RARA fusion transcripts demonstrated by reverse transcriptase-PCR and cDNA sequencing, and no PML/RARA fusion detected by karyotype and FISH analyses. Karyotype was 47,XX,+8[19]/46,XX[1]. Although the newer FISH probes provide more accurate detections of t(15;17), it would be necessary to perform other molecular tests to further identify the masked PML/RARA fusions.