Yu A, et al. - Researchers aspired to contemplate the correlation between the clinical and histopathological classifications of actinic keratosis (AK) and the efficacy of topical imiquimod treatment. Results revealed that the topical imiquimod treatment was possibly more effective for AK clinically classified as the erythematous type, or histopathologically classified as the atrophic or hypertrophic type. Hence, the efficacy of topical imiquimod therapy in AK could be speculated by determining its clinical and histopathological type.