Retroperitoneal fibrosis mimicking a rectal tumor: Report of a case

PURPOSE: The study contained herein was undertaken to report an original case of retroperitoneal fibrosis that resembled a rectal tumor both symptomatically and radiologically. METHOD: Reported is a case of retrorectal fibrosis with a brief literature review of the topic. RESULT: Although many forms of retroperitoneal fibrosis have been reported, extension below the pelvic rim is very unusual. Compression of the rectum and right ureter, with constipation as a chief complaint, made this case presentation unusual. Although computerized tomographic findings and needle biopsies supported the diagnosis of retroperitoneal fibrosis, an exploratory laparotomy was necessary to rule out a malignancy and to release the ureter. CONCLUSION: A fibrotic mass involving the retrorectal region may mimic a rectal tumor. To reach a final diagnosis, an exploratory laparotomy may be necessary, despite sophisticated evaluation techniques, because it is difficult to differentiate whether the mass is malignant.