Porokeratosis simulating Bowen's disease on dermoscopy.

Porokeratosis is a disorder of epidermal keratinization characterized by the presence of annular hyperkeratotic plaques. Its etiopathogenesis is not yet fully understood, but a relationship with immunosuppression has been reported. Dermoscopic examination revealed a classic yellowish-white ring-like structure that resembled "volcanic crater contour" - the so-called cornoid lamella. We describe a case of porokeratosis in a female patient with chronic lymphedema, which was similar to Bowen's disease due to the many glomerular vessels seen on clinical examination and dermoscopy.