Hydroxyurea-induced leg ulcers: is macroerythrocytosis a pathogenic factor?

Hydroxyurea is a common cancer chemotherapy agent that inhibits ribonucleotide reductase, an enzyme essential to DNA synthesis. It is considered the drug of choice in the treatment of chronic myelogenous leukemia and essential thrombocythemia. The occurrence of leg ulcers have been described in 8.5% of patients receiving continuous treatment with hydroxyurea, but the cause of this complication is unknown. We report two additional patients and suggest that macroerythrocytosis, which occurs in almost all the patients taking hydroxyurea, may be a pathogenic factor. Macroerythrocytosis can be considered as an 'acquired' blood dyscrasia, and similar leg ulcers have long been known to occur with certain hereditary blood dyscrasias, such as sickle cell anemia, thalasemia, and spherocytosis.