Erlotinib-responsive actinic keratoses.

Erlotinib is an inhibitor of the tyrosine-kinase domain of the epidermal growth factor receptor-1 (EGFR). This drug is used to treat some solid cancers, particularly advanced non-small-cell lung carcinoma. Similar to other EGFR inhibitors, erlotinib is responsible for a series of skin adverse reactions, particularly acneiform lesions. We described the incidental effect of erlotinib on actinic keratoses which became markedly inflamed and showed partial regression. Inflammation appeared to spontaneously decrease while on erlotinib treatment. This reaction in the skin neoplasm is perhaps a visible and accessible model for predicting the effect in the deep-seated neoplasm targeted by the drug.