Case for diagnosis.

Focal acral hyperkeratosis is a rare genodermatosis with an autosomal dominant pattern of inheritance. It is characterized by usually asymptomatic keratotic papules along the borders of the hands and/or feet. The main differential diagnosis is acrokeratoelastoidosis of Costa, which differs from the former only by not presenting elastorrhexis in histopathological examination, thus requiring this exam for a correct diagnosis.