[Giant pore and hair-shaft acanthoma. Clinical and histologic diagnosis].

This report presents clinical and histological data of dilated pores of 54 biopsies from 45 patients from Munich and 39 biopsies from 36 patients from Detroit. The dilated pore of Winer is a relatively common benign adnexal tumor originating from the outer hair root sheath. Three-dimensional reconstructions of the tumor show that four different types of dilated pores can be considered. The dilated pore is a tumor sui generis and not a trichoepithelioma. A second benign adnexal tumor, the pilar sheath acanthoma of Mehregan and Brownstein, is presented in 11 biopsies from 11 patients from Munich and in nine biopsies from nine patients from Detroit. Clinical and histological features and differential diagnosis are shown.