[739] Inflammatory Bowel Disease Associated with Primary Sclerosing Cholangitis Has Different Phenotypes: PSC-IBD vs. IBD-PSC

David F Schaeffer, Sara Hafezi-Bakhtiari, Maria Cino, Gideon M Hirschfield, Hala El-Zimaity. University Health Network, Toronto, ON, Canada

Background: Inflammatory bowel disease (IBD) associated with primary sclerosing cholangitis (PSC) is reported to be mild and prone to right-side predominance with rectal sparing. While IBD onset often follows the diagnosis of PSC the opposite may occur; no data are available on possible differences. Thus, we examined colonic disease distribution and severity based on primary disease presentation (colonic versus hepatic).
Design: We identified patients with PSC and IBD seen at the University Health Network-Toronto between 1995 and 2011. Colonic biopsy specimens were independently reviewed in a blinded fashion. When available, each colonic region was assessed on a six-grade scale (0 to 5) for architectural distortion, Paneth cell metaplasia, and degree of inflammation. Clinical, endoscopic, and follow up data were collected. Patients were divided into two groups based on site of first disease presentation: group 1, colitis first (IBD-PSC) and group 2, sclerosing cholangitis first (PSC-IBD). We excluded patients in whom information on disease presentation was not available (n = 12). We then compared both groups for disease distribution and severity.
Results: We examined 58 patients (54 with ulcerative colitis and 4 with Crohn's disease). Colitis preceded liver disease in 28 patients (IBD-PSC). Colitis followed liver disease in 30 (PSC-IBD). Colitis, in both groups, was mild with focal deep plasmacytosis and occasional mild cryptitis - more severe active cryptitis was not identified. Individual biopsies from both right and left regions of the colon were available in 42 patients only. IBD preceding PSC had a tendency to have a 'pan-colitis' distribution, see table – this group included all patients with Crohn's disease. IBD following PSC was more likely right-sided (sparing the descending and sigmoid colon and rectum (p = 0.012)).

DistributionIBD-PSC (n=22)PSC-IBD (n=20)
Right sided (only)513
Left sided (only)10

Conclusions: The histological picture of both groups (IBD-PSC and PSC-IBD) is distinctively mild, but the distribution tends to be pancolitis in the IBD-PSC group and right sided ulcerative colitis in the PSC-IBD group. This suggests that patients with what appears to be right sided ulcerative colitis might be a separate phenotype associated with PSC and should lead to consideration of evaluation of liver function tests if not already carried out.
Category: Gastrointestinal

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 107, Monday Morning


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