Bowel compression on the gallbladder mimicking a gallstone on cholescintigraphy

A photopenic defect was noted over the gallbladder on cholescintigraphy, which has been previously described in the literature as a sign of cholelithiasis. It changed in size and appearance during the course of the examination. An ultrasound examination revealed no cholelithiasis. How ever, there was a loop of colon juxtaposed to the gallbladder, which intermittently indented the wall. This was the only explanation for the photopenic defect observed on cholescintigraphy. Recognition of this possibility may prevent misdiagnosis of cholelithiasis on cholescintigraphy.