Purpose: Only a few studies have documented the characteristics of inflammatory bowel disease (IBD) associated with primary sclerosing cholangitis (PSC). We aimed to clarify the clinical and histopathological characteristics of IBD associated with PSC (PSC-IBD).
Methods: Twenty-nine patients with PSC and 60 patients with ulcerative colitis (UC) but without complicating PSC were enrolled in this study. First, the age and sex distribution, affected area, clinical course, number of recurrent attacks, and severity of UC were investigated. Then, mucosal specimens obtained from the right side (cecum and ascending colon), transverse colon, and the left side (descending colon, sigmoid colon, and rectum) during colonoscopy were studied for inflammatory cell infiltration, the presence of crypt abscesses, the degree of goblet cell disappearance, and edema.
Results: (1) The incidence of IBD in PSC patients was 68.9% (20/29). There were two peaks in the age distribution of PSC. Male PSC patients demonstrated a first peak and female patients a second peak. Male PSC-IBD patients were in their teens and 20s making the first peak. Female PSC-IBD patients were in their 50s and 60s making the second peak. The PSC-IBD patents were significantly younger than the patients without IBD (33.6 vs. 58.9 years, p < 0.001). (2) PSC-IBD showed a right-sided predominance colonoscopically. (3) None of the patients had a severe clinical course, and a half of them were asymptomatic. (4) Histopathological examination demonstrated severe inflammatory cell infiltration in the cecum and ascending colon, whereas the degree was mild in the rectum/descending colon.
Conclusions: PSC-IBD shows characteristic clinical, colonoscopic, and histopathological findings.