Huge cystic duplication of the ascending colon in adult.

Duplications of alimentary tract are uncommon congenital anomalies that are usually identified during the pediatric age. However, a minority of cases remain unsuspected until adulthood. They may be cystic or tubular in appearance and characteristically arise from the mesenteric border of the intestine. This paper reports a 37-year-old male with a huge cystic duplication of the ascending colon. In facing such a huge abdominal cystic tumor, differential diagnoses including duplication cyst, mesenteric cyst, choledochal cyst, giant diverticulum, and cystic tumor of the pancreas should be considered. Computerized tomography is a good tool for delineating the relationship between the tumor and peripheral structures. Surgery not only provides treatment but also final pathological diagnosis. Complete resection of a colonic duplication is necessary because of potential malignant change of the lesion.