Adenomyomatosis is a benign condition characterized by hyperplastic changes of unknown etiology involving the gallbladder wall. It causes overgrowth of the mucosa, thickening of the muscular wall, and formation of intramural diveicula or sinus tracts termed as Rokitansky-Aschoff sinuses. Ultrasound shows a thickened gall bladder wall, punctate hyperechoic reflectors with comet tail aifacts.