Acute leukemia as a transformation after polycythemia vera.

The development of acute leukemia as a natural progression of polycythemia vera is very rare. We have described a patient who had acute leukemia within one month after the diagnosis of polycythemia vera, which was treated only with phlebotomy on three occasions. Chromosomal study in the leukemic phase showed no abnormality, and the terminal deoxynucleotidyl transferase was positive.