A patient had typical keratosis follicularis (Darier disease). During the course of his treatment, he complained of pruritus ani. Subsequently, involvement of the rectal mucosa by the disease process was demonstrated by proctoscopy and examination of the biopsy specimen.
Klein A, Burns L, Leyden JJ. Rectal Mucosa Involvement in Keratosis Follicularis. Arch Dermatol. 1974;109(4):560-561. doi:10.1001/archderm.1974.01630040066019