Crypt abscesses, crypt distortion, and crypt rupture may help distinguish inflammatory bowel disease from segmental colitis associated with diverticulosis.

The histologic distinction of segmental colitis associated with diverticulosis (SCAD) from inflammatory bowel disease (IBD) is difficult; however, distinguishing the two is important for patient management. This study aimed to examine histologic changes in SCAD and compare them to those in IBD. We retrospectively identified patients with highly likely SCAD and known IBD who were biopsied at our institution. With diagnosis blinded, H&E slides were reviewed for cryptitis, crypt abscesses, lamina propria (LP) neutrophils, erosion/ulceration, LP expansion by mononuclear cells, prominent basal lymphoid aggregates, basal lymphoplasmacytosis, crypt distortion, crypt dilation, granulomatous reaction to damaged crypts, increased intraepithelial lymphocytes, mucin depletion, Paneth cell metaplasia, LP smooth muscle wisps, and crypt rupture. Features between groups were compared by chi-squared analysis, with statistical significance set at P < 0.05. There were 81 SCAD cases (79% in the sigmoid colon) and 166 IBD cases. A separate cohort of 27 patients had both IBD and diverticulosis. Compared to the IBD cohort, the SCAD cohort was significantly less likely to demonstrate crypt abscesses (20% vs. 45%, P < 0.0001), prominent basal lymphoid aggregates (37% vs. 51%, P = 0.042), crypt distortion (7% vs. 25%, P = 0.00090), Paneth cell metaplasia (37% vs. 57%, P = 0.0061), and crypt rupture (1% vs. 11%, P = 0.0089). These histologic features, although not entirely specific, may be of value in distinguishing IBD from SCAD, particularly when clinical context is unclear or not readily available.