Three patients had diverticulitis and extraintestinal manifestations of arthritis and pyoderma gangrenosum. In each, a mistaken diagnosis of idiopathic inflammatory bowel disease was first made because of extraintestinal complaints associated with the gastrointestinal symptoms of diverticular disease. The joint and skin manifestations were refractory to various treatments, including oral and intradermal steroids, immunosuppressive agents, and hyperbaric oxygen. Segmental resection of the involved colon promptly and completely resolved all symptoms, without recurrence 26 to 38 months after surgery. Microscopic examination of the resected specimens showed only diverticulitis without any evidence of chronic idiopathic inflammatory bowel disease. Patients with diverticulitis may have extraintestinal manifestations as do patients with other inflammatory diseases of the colon. The failure to recognize this relationship may result in misdiagnosis and prolonged medical therapy, whereas segmental colonic resection may be curative.

Klein, Mayer, Present, Youner, Cerulli, Sachar (1988). Extraintestinal manifestations in patients with diverticulitis. Annals of internal medicine, 1988 May;108(5):700-2. https://www.ncbi.nlm.nih.gov/pubmed/3358570