Acute promyelocytic leukemia with t(15;16;17;19) and unusual fluorescence in situ hybridization pattern with PML and RARA probes.

We report a 58-year-old female with typical morphological and clinical features of acute promyelocytic leukemia in whom a complex translocation involving chromosomes 15, 16, 17 and 19 was detected using conventional cytogenetics and fluorescence in situ hybridization (FISH) with chromosome specific paints. RARA-PML fusion was not evident by FISH, but the RARA signal was split in 74.5% of cells. GTL-banding and FISH with probes for PML, RARA and chromosome 15 specific paint raise the possibility of PML-RARA fusion on the abnormal chromosome 19 in the complex translocation. The unusual PML-RARA fusion may be related to this patient's poor response to induction therapy with all-trans-retinoic acid.