It is one of only a few published cases with hyperdiploidy, t(1;19)/der(19)t(1;19), and a confirmed TCF3-PBX1 fusion in B-ALL, demonstrating the importance of using FISH and PCR for proper cytogenetic and molecular classification in order to distinguish the present scenario from hyperdiploid B-ALL with t(1;19)/der(19)t(1;19), but lacking the TCF3-PBX1 fusion. Here, PBX1 is linked to acute lymphoblastic leukemia.