We report a dermoscopic diagnostic clue for non-pigmented eccrine poroma found in a collarette, which is thought to be a nonspecific site.

The tumor of a patient with Bowen’s disease exhibited expression of the tumor suppressors p53 and p16INK4a(p16), which correlated with cytoplasmic expression of the histone deacetylase sirtuin 1(SIRT1). Epigenetic regulation of p53 and p16 by SIRT1 may play a role in the carcinogenesis of Bowen’s disease.