Psoriasis of the Mucous Membranes

Psoriasis of the mucous membranes is one of the rarest of dermatologic conditions. Its existence has always been a subject for debate, and to the present day some authorities maintain it does not occur. Darier¹has only recently denied its existence, and Jadassohn has admitted the possibility of its presence only from reports in the literature. REVIEW OF THE LITERATURE In reviewing the literature it is impossible to determine definitely when the writers of the last century were dealing with psoriasis and when with leukoplakia, as the terms were being used synonymously. It was not until 1903 that Oppenheim and Thimm reported the first cases with histologic examination. Oppenheim's patient²presented several plaques, entirely different in appearance from leukoplakia, on the buccal mucosa, the palate and the left palatal vault. The plaques were gray or yellowish white, round or oval and sharply circumscribed. They formed a network with