Background: Diverticular associated colitis (DAC) has become increasingly appreciated as a form of inflammatory disease, localized mainly in the sigmoid, and defined as chronic inflammation of the interdiverticular mucosa with sparing of rectum, right colon and diverticula themselves.

Methods: A retrospective case identification from January 2005 to December 2016 was performed. Patients with a diagnosis of DAC based on clinical, endoscopic and histological findings were enrolled. We analyzed their characteristics and response to therapy, and performed a review of literature.

Results: Out of 377 pathology reports, 37 cases of DAC were identified, with a median age of 73 years and followed during 1-13 years. Six patients (16.22%) were refractory to conservative treatment and required surgery. In three patients (8.11%) evolution to ulcerative colitis (UC) was observed. Patients were divided into four endoscopic patterns, with a more benign course for type A "crescentic fold disease" compared to the other subtypes. Patients with type B "mild to moderate ulcerative colitis-like" were at significantly higher risk of persistent disease activity or relapse (p < 0.01).

Conclusions: DAC is a multifaceted disease and considered to be a relatively benign condition. However, a subset of patients requires surgery and/or may progress to develop UC.