SQUAMOUS CELL METAPLASIA OF RECTUM COMPLICATING LONGSTANDING ULCERATIVE COLITIS, A "REVERSED BARRETT'S" CONFIGURATION

H Chaun, P Zetler

Division of Gastroenterology, Department of Medicine and Department of Pathology, St. Paul's Hospital and University of British Columbia, Vancouver, British Columbia

The endoscopic appearance of squamous cell metaplasia (SCM) of the rectal mucosa in association with ulcerative colitis (UC) has not been reported previously. This unique finding occurred in an elderly woman with a longstanding history of UC.
CASE REPORT: A 71-year-old white woman, a non-smoker, had a hemorrhoidectomy at age 28, following which she developed colitis manifested by diarrhea and abdominal pain. At age 44, she had eight inches of the colon removed because of a stricture and an abscess. Over the years, she had occasional rectal bleeding whenever she was "stressed". A double contrast barium enema in 1992 showed a shortened featureless colon compatible with chronic UC in remission. In October 1999, she presented with a 3-month history of persistent intermittent rectal bleeding. She had a 33-year-old son with Crohn's disease. She had a long midline abdominal surgical scar; physical examination was otherwise unremarkable. Her hematological parameters were normal. Colonoscopy showed absence of haustral folds throughout the left colon, and small elongated pseudopolyps scattered along the distal half of the colon, compatible with the history of UC; there was no evidence of acute disease. In the distal few centimetres of the rectum, there was a remarkable appearance of diffusely pale mucosa surrounding islands of intensely reddened mucosa and between two prominent "tongues" of the reddened epithelium extending distally. Biopsies of the pale areas revealed benign squamous epithelium.
Most reports of SCM of the rectum have been associated with rare primary squamous cell carcinoma and with rectal tubular adenomata. SCM of the rectum in UC is extremely rare, with only one other documented case identified in the literature, demonstrated histologically. The unique endoscopic finding in this patient of extensive rectal SCM presenting as a "reversed Barrett's" configuration has not been reported previously.