Case Report Colonic Duplication in Adult Presented as Chronic Constipation Attributed to Hypothyroidism Running Title: Colonic Duplication in Adults

Gastrointestinal duplications are uncommon congenital abnormality in 80% of cases and manifest before the age of 2. Ileal duplication is the most common while colonic duplication, either cystic or tubular, occurs in 10-15% of cases and remains asymptomatic and undiagnosed in most cases. Mostly occurring in pediatric patients, colonic duplication is encountered in adults only in a few cases. The most common clinical manifestations are abdominal pain and intestinal obstruction. Rarely, such duplications present with signs of acute abdomen or acute bleeding. This study reports a case of colonic duplication in adult presented with chronic constipation. Complete diagnostic workup was made in several occasions during 8-years period but no pathology was found and chronic constipation was attributed to hypothyroidism caused by long standing Hashimoto thyroiditis. Multislice CT made because of abdominal distension defined colonic pathology but definite diagnosis of duplication of transversal colon was made at operation. The cystic duplication and the adjacent part of the ascending and transversal colon were excised en-block. The study implies that colonic duplication, though uncommon, should be included in the differential diagnosis of chronic constipation even when precipitating factors for constipation, such as hypothyroidism are present.