Oral squamous cell carcinoma during long-term treatment with hydroxyurea.

Hydroxyurea (HU) is commonly used for the treatment of chronic myelogenous leukaemia, polycythemia vera and essential thrombocythaemia. Patients receiving HU present a number of side-effects including skin/mucosa changes and tumours. Mucocutaneous abnormalities include xerosis, ichthyosiform lesions, dark brown pigmentation of skin folds and nails, malleolar ulcers, oral mucositis and oral ulcers. Cutaneous squamous/basal cell carcinomas have also often been reported following long-term administration of HU. HU-induced carcinogenesis is due to both the mutagenic potential of this agent and to an impairment of DNA repair mechanisms after damage by external factors such as ultraviolet radiation. Oral cancer following long-term treatment with HU has been reported only once, in a patient with concomitant multiple skin tumours. We present the unique case of a patient with polycythemia vera who developed oral cancer after 15 years of HU therapy.