Primary retrorectal adenocarcinoma: report of a case.

Primary adenocarcinomas of the retrorectal (presacral) space are uncommon and usually arise from cystic lesions developing from remnants of the embryological postanal gut (tail gut cysts) containing mucous-secreting epithelium. A singular case of a patient who presented with a retrorectal mass is described. A 70-year-old previously healthy man had a four-month history of perianal pain during defecation.