Transformation of polycythemia vera to Ph-positive chronic myelogenous leukemia

A patient with polycythemia vera (PV) developed chronic myelogenous leukemia (CML) 8 years after his initial presentation with erythrocytosis. The patient received a total of 3.5-7 g of chlorambucil over an approximate period of 5 years. Transformation of PV to CML is very unusual; only three substantiated cases had been reported in literature until 1975, and none has been described since then. All patients received either 32P or chemotherapy for PV treatment, suggesting that irradiation and alkylating agents may have played a role in the transformation to CML.