Transition of polycythemia vera to chronic myeloid leukaemia

: A 77‐year‐old female with polycythemia vera (PV) showed a sudden, typical chronic myeloid leukaemia (CML), 8 yr after the initial diagnosis, and an intermittent treatment with hydroxyurea (0.5–1 g/d) and phlebotomies. At PV diagnosis, the Ph chromosome was negative and no bcr–abl rearrangement was observed; they were both revealed positive at CML onset. Transition of PV to CML is very rare; only seven substantiated cases had been reported in the literature up until now (six from 1964 to 1993). All patients but one received 32P or alkylating agents for PV treatment. The pathogenetic mechanisms are briefly discussed.