Asymptomatic anisakiasis of the colon incidentally found by colonoscopy.

Asymptomatic anisakiasis of the colon is a rare condition that is difficult to diagnose. A 42-year-old man with no symptoms was referred to our department because of elevated serum carcinoembryonic antigen (CEA) levels detected previously at another hospital. A colonoscopy was performed to find the reason for these elevated CEA levels, and Anisakis larvae were identified by chance in the ascending colon wall. This is only the fourth case of asymptomatic anisakiasis of the colon to be reported worldwide.