Atypical chronic myeloid leukemia following organ transplants

:  Secondary malignancy frequently develops among recipients of organ transplants, most commonly malignancies of the lymphoid system and skin. However, chronic myeloid leukemia (CML) is rare following transplant, with only a handful of cases reported, all of whom had kidney transplant and received azathioprine for immunosuppression. We report three cases of post-transplant CML seen at a single institution within a two-yr period. Two had received liver and one a kidney transplant. None were on azathioprine but all had tacrolimus. CML is a rare hematological malignancy, usually presenting with high white counts and splenomegaly. In all three of our subjects, presentation of CML post-transplant was so atypical that their diagnosis could easily be missed. All had rapid and excellent response to imatinib, and underwent clinical remission. This is the first report of CML developing in the course of tacrolimus therapy among liver transplant recipients. Presentations of CML were highly atypical and easy to miss in early stage. Awareness of atypical CML developing post-transplant is important since early and timely therapeutic intervention with imatinib is critical for improving quality of life and overall prognosis.