A patient complains to his physician of chronic constipation. On the instruction of his physician, the patient increases his dietary fiber, but his constipation persists. The physician refers the patient to a gastroenterologist. Colonoscopy reveals over fifty 2-3 mm openings into the bowel mucosa. No bleeding is seen, and the intervening mucosa appears normal. Which of the following is the most likely diagnosis?

The appearance described is typical for diveiculosis. The openings seen are into diveicula, which are small, acquired outpouchings of the mucosa through the muscle of the bowel. Milder cases of diveiculosis are usually asymptomatic; patients with extensive diveicula may experience mild cramps, bloating, or constipation. In amebiasis, the patient would have much more severe symptoms and bleeding would probably be present. In Crohn disease, pseudomembranous colitis, and ulcerative colitis, the mucosa would appear obviously diseased.