Idiopathic myelofibrosis in blast transformation with 4;12 and 5;12 translocations and a 7q deletion.

A case of a patient who developed a leukemic transformation following an 8.5-year history of idiopathic myelofibrosis (IMF) with myeloid metaplasia is presented. Surface marker analysis identified the blast cells as myeloid in lineage. The karyotype of unstimulated peripheral blood cells was 46,XY,t(4;12)(q26;15),t(5;12)(q13;q24),del(7)(q22). In the literature, the 7q- has a minor association with IMF, and the t(5;12) translocation has been reported in one case of acute nonlymphocytic leukemia, but neither the t(4;12) nor the combination of these three abnormalities has been reported in IMF.