Case Discussion
Darier disease (keratosis follicularis) is a rare autosomal dominant genodermatosis due to mutations in gene ATP2A2. It is characterized by greasy, crusted, keratotic papules and plaques in seborrheic regions, nail abnormalities, and mucous membrane changes. This skin biopsy from the shoulder contains epidermis, dermis and subcutis. In the epidermis, there are foci of suprabasal clefting with acantholytic dyskeratotic cells and overlying vertically orientated parakeratotic columns, which are hallmarks of Darier disease.
