[Centrifugal plaques with central atrophy and peripheral scale on the scalp]

A 62-year-old man presented with slowly progredient, centrifugal, peripherally hyperkeratotic, centrally atrophic, slightly pruritic lesions on his scalp for at least 9 months. A punch biopsy stained with hematoxylin-eosin (HE) revealed minimal epidermal acanthosis and chimney-like parakeratosis (cornoid lamella) around a follicle. Discrete spongiosis of the epidermis was observed, as well as a lymphocytic cell infiltration in the papillary dermis. Based on the clinical picture and the histopathological examination the diagnosis of porokeratosis of Mibelli was made. Topical treatment was started using an urea and vitamin A acid preparation.