2094 Segmental Colitis Associated With Diverticulosis Progressing to Ulcerative Colitis: An Under-Reported Occurrence

Abstract

INTRODUCTION: Segmental colitis associated with diverticulosis (SCAD) is chronic inflammation of the interdiverticular mucosa, usually involving the sigmoid colon. This entity may mimic ulcerative colitis (UC) in its clinical manifestations and endoscopic appearance, however unlike UC, the rectum is usually spared. We report a rare case of SCAD progressing UC. CASE DESCRIPTION/METHODS: A 59-year-old female was referred for an outpatient colonoscopy for evaluation of a two-month history of hematochezia and diarrhea. Past medical history was significant for gastroesophageal reflux disease with esophagitis. Physical examination revealed no tenderness in the abdomen and normal bowel sounds. Rectal exam revealed small non-bleeding external hemorrhoids. Laboratory examination was significant for a low hemoglobin of 11.4 g/dL. Colonoscopy revealed patchy loss of vascular pattern, edema and hyperemia in the sigmoid colon associated with several large diverticula. Rest of the colon including the rectum and terminal ileum was unremarkable. Histologic evaluation of the specimens taken from the inflamed sigmoid colon showed expansion of the lamina propria with moderate chronic inflammation. No acute inflammation including acute cystitis or crypt abscess was present. The patient was diagnosed with SCAD and prescribed a two-week course of antibiotics with partial improvement in her symptoms. The patient was lost to follow-up for two years and presented again with hematochezia and iron deficiency anemia. A repeat colonoscopy revealed mild rectal erythema and an interval increase in inflammation of the sigmoid colon typical for UC. Several pseudopolyps were also seen. Histologic examination of the specimens taken from the sigmoid colon and rectum showed severe chronic active colitis with crypt architectural distortion compatible with UC. Crypt architectural distortion was also noted in the remaining endoscopically normal colon. DISCUSSION: The pathogenesis of SCAD remains unclear, however, mucosa prolapse, fecal stasis and localized ischemia is frequently implicated. Even though SCAD is recognized an independent disease progress, there have been reports of cases of SCAD progressing to inflammatory bowel disease (IBD). A high index of suspicion should be kept for patients with SCAD who do not respond to the main stray of treatment with antibiotics, anti-inflammatory agents and steroids. Also, patients with SCAD should be considered for close follow-up and surveillance endoscopy as this disease may co-exist or progress to IBD.