[Encysted gossypiboma of the lesser omentum: complementary aspects of echography and computerized tomography].

The authors report the fortuitous demonstration of an asymptomatic gossypiboma during the preoperative staging of a rectal carcinoma 13 years after abdominal surgery for perforated gastric ulcer. Ultrasonography disclosed a well-defined hypoechoic mass containing highly echogenic foci with a strong posterior shadow. The CT findings are reported, as well as the complementary aspects of sonography. Differential diagnosis from tumors of the lesser omentum is also presented.