Translocation t(12;13)(p13;q14) in a patient with imatinib-sensitive MDS/MPD associated with resistance to treatment: review of the literature.

The category of myelodysplastic syndromes/myeloproliferative diseases (MDS/MPD) is a relatively new group of malignant hematologic diseases developed by the World Health Organization. These hematologic disorders lack the BCR/ABL fusion gene, although they can be associated with chromosomal translocations that involve genes encoding other protein kinases. Imatinib mesylate was recognized as a potent inhibitor of some of those kinases. We present a patient with a previously treated acute myeloid leukemia, who, after a 9-year-long remission, developed an MDS/MPD with normal karyotype, which initially responded to imatinib mesylate. Translocation t(12;13)(p12;q14) was detected after loss of response to imatinib treatment. Translocation t(12;13) is rare. It has been described in several hematologic malignancies including chronic myelomonocytic leukemia but not in MDS/MPD, previously described as Philadelphia-negative chronic myelogenous leukemia. Moreover, the correlation of this molecular abnormality with loss of efficacy of imatinib is unique in the literature.