Painful oral mucosal ulcers in a patient with small cell carcinoma of the lung.

This case illustrates the development of multiple painful oral ulcers caused by methotrexate that was one of a combination of chemotherapeutic drugs administered for the treatment of small cell carcinoma of the lung. Although the oral mucositis is self-limiting and resolves when the drug dose is reduced or therapy is discontinued, severe pain and discomfort may cause physical debilitation. Moreover, the risk of secondary oral infections is high in patients undergoing such therapy, and if the appropriate treatment is not instituted, fatal systemic dissemination of the infection may occur.