Abdominal sonography in 7 patients with acute biliary disease revealed focal echo collections within the wall of the gallbladder in addition to cholelithiasis and diffuse mural thickening. A prospective study was conducted, comparing in vivo and in vitro sonography of the gallbladder with histopathological findings. In 3 patients, microscopy of the hyperechoic tissue showed microabscesses. In 4, intramural diverticula containing inspissated bile, small stones, or cholesterol crystals were seen. The authors caution that hyperechoic foci within the wall of the gallbladder may indicate intrinsic disease separate from cholelithiasis or cholecystitis.