A Woman With Pruritus Ani

Abstract

Question: A 79-year-old woman with no medical history presented to our hospital with pruritus ani. A well-defined, circular, erythematous, hypopigmented macule measuring 15 mm in diameter was observed around the anus (Figure A). The patient had no gastrointestinal symptoms, and laboratory findings, including serum carcinoembryonic antigen and carbohydrate antigen 19-9 levels, were normal. Examination of biopsy specimens of the hypopigmented skin lesion showed Paget’s cells. Immunohistochemical staining of the skin lesion was positive for cytokeratin (CK)-20, but negative for gross cystic disease fluid protein (GCDFP)-15. Digital rectal examination revealed a 10-mm, semipedunculated, movable polyp in the lower rectum adjacent to the anal canal. Colonoscopic examination revealed a 10-mm, semipedunculated polyp on the proximal side of the dentate line in the lower rectum (Figure B). Biopsy specimens of the rectal polyp revealed moderately differentiated adenocarcinoma. A wide local excision of the perianal skin including the mucosa of the anal canal and lower rectum was performed. What is the diagnosis? Look on page 1160 for the answer and see the GASTROENTEROLOGY web site (www.gastrojournal.org) for more information n submitting your favorite image to Clinical Challenges and Images in GI.