Keratoacanthoma aggravated after photodynamic therapy

Abstract

Keratoacanthoma (KA) is a relatively common epithelial tumor and may develop at sites of previous trauma. Most cases grow rapidly then undergo spontaneous regression, leaving an atrophic scar. But some cases of KA cause destructive variants without regression and persistent invasive growth. A 54-year-old man first visited our hospital with a tumor on ala of the nose. The tumor developed 4 months prior, grew in the first 2 months and stopped growing in next 2 months. The tumor was 1 cm in diameter at first visit, and was an exophytic, well demarcated and erythematous nodule with central keratotic plug (Fig. 1a) and KA was proved by histopathological examination. The patient refused to undergo surgical procedure because he was worried about it leaving scars on his face after surgery. Therefore, we decided to perform topical photodynamic therapy (PDT). Methyl aminolevulinate (MAL) cream (Metvix; Galderma, Paris, France) applied to the tumor under occlusion for 3 h.