Fluorescence in situ hybridization (FISH) detected two CEBPE-IGH rearrangements at the dup(14).     ///    Double CEBPE-IGH rearrangement due to chromosome duplication and cryptic insertion in an adult with B-cell acute lymphoblastic leukemia..     ///    Our findings confirm that deregulated CEBPE plays a crucial role in the pathogenesis of CEBPE-IGH positive B-ALL..     ///    This case provides the first evidence that chromosome duplication and cryptic insertion produce the CEBPE-IGH fusion and that more than one CEBPE-IGH recombination can occur in a leukemic cell. 