Giant diverticular of the sigmoid colon: a review of differential diagnosis and operative management.

Giant sigmoid diverticula ("giant gas cysts," "giant sigmoid cysts") are an unusual complication of diverticulitis. We have recently seen two patients with such lesions, bringing the total number of reported cases to 48. Most patients are elderly and complain of abdominal pain or the presence of an abdominal mass. Air trapping by a ball-valve mechanism may be responsible for formation of the fibrous cysts. The gas-filled structures can usually be differentiated from other conditions by contrast studies. Excision of the cyst and adjacent colon with anastomosis can usually be accomplished safely under elective circumstances.