Cholangiocarcinoma that was incidentally found in patient with opisthorchiasis.Transverse sonogram of middle age man who was included in sonographic survey in village near Vientiane, Laos shows 3.0 cm mass (arrows) associated with dilatation of bile ducts peripheral to mass (arrowheads). CT image of same patient showed mass, which was consistent with cholangiocarcinoma (not shown).