A rare t (9; 12; 22) (q34; q23; q11) translocation in a patient with typical chronic myeloid leukemia: A case report

Chronic myeloid leukaemia (CML) is typically associated with reciprocal translocation between long arms of chromosome 9 and 22, t (9, 22) (q34; q11.2) and with the formation of a BCR-ABL fusion gene. In a minority of newly diagnosed CML cases, complex cytogenetic variants of the Ph chromosome can be observed with involvement of chromosomes 9, 22 and a third chromosome. Herein, we describe a lady with CML in chronic phase with a complex translocation involving chromosomes 9, 22 and 12. Conventional karyotyping revealed t (9, 12). Fluorescence in-situ hybridization (FISH) showed BCR-ABL fusion signals in 60% nucleated cells (cut-off levels ≥5% for positive signals). Whole chromosome painting (WCP) showed presence of a complex variant translocation between chromosomes 9, 12 and 22. However, DNA analysis for BCR-ABL fusion gene was negative. Cytoreductive therapy and Imatinib treatment were initiated.