Darier disease (follicular dyskeratosis) is a rare genodermatosis determined by an autosomal dominant gene with variable penetration, characterized by a symmetrical eruption of hyperkeratotic papules with predilection to the seborrheic areas of the body. Unilateral, focal form is the one of the rare type of the Darier disease. Two clinical and genetical phenotypes of the segmental Darier disease have been recently reported: type 1--in which the skin outside of the localized manifestation is normal and type 2--showing a segmental affection in combination with diffuse skin involvement. The patient with type 1 segmental Darier disease is presented because of rare occurrence, diagnostic and therapeutic difficulties as well. The first keratotic papules on the left side of his trunk appeared at the age 14. The correct diagnosis based on clinical and histological picture has been established 38 years latter.