Lymphocytic colitis pattern of injury presenting as endoscopic polyps: a case series

Lymphocytic colitis (LC) is characterized by chronic watery diarrhea and unremarkable endoscopic findings. Only one case of LC presenting as multiple colonic polyps has been reported. We report a case series of histologic LC pattern of injury (LCPI), presenting as endoscopic polyps, and compare them with typical LC cases. Eighteen archived (2009-2019) polypoid LCPI cases without an associated cause of polyp, such as adenoma, hyperplastic change, or lymphoid aggregate, were retrieved from 17 (12 female and 5 male) patients. The clinical history and endoscopic findings were noted. A total of 40 conventional LC cases were used as controls. Fisher's exact test was performed to evaluate associations between two variables. The mean age of the patients was 61.1 years. The indication for colonoscopy was chronic watery diarrhea (56%), screening/surveillance (33%), and rectal bleeding (11%). The mean number and size of the polyps was 1.6 and 2.9 mm, respectively. Seventy-six percent were located in the left colon, and 48% were sessile. When biopsied (14/18; 78%), the background colonic mucosa showed LCPI. There was no significant difference in age, gender, and the average number of lymphocytes in the two groups. Hypertension and history of malignancy was more common in the polypoid LCPI group than in the control LC group (P < 0.05). LCPI may present as endoscopic polyps, frequently in patients with hypertension and history of malignancy. Polypoid LCPI may be a harbinger of LCPI in the background nonpolypoid colonic mucosa. A subset of polypoid LCPI (56%) cases represents true LC.