[ADENOMYOMATOSIS, GALLBLADDER]. Adenomyomatosis most likely represents glandular diverticulae into the muscle wall. This may be focal process or diffuse involving the entire gallbladder. This non-neoplastic change is thought to have resulted from chronically elevated intraluminal pressure causing Rokitansky-Aschoff sinuses to extend beyond their usual size to accommodate extra bile. The “myomatous” component of adenomyomatosis represents muscular hypertrophy because of increased intraluminal pressure. The bid arrow represents gallbladder lumen whereas the left arrow shows dilated sinuses in the muscle layer of the fundus.
[ADENOMYOMATOSIS, GALLBLADDER]. The dilated sinuses (arrow) in the fundic muscle layer are always connected to the lumen via channels (top arrowhead) as seen in this case. Note the presence of bile in the sinus consistent with its connection with the main lumen.
[ADENOMYOMATOSIS, GALLBLADDER]. The photomicrograph shows muscular hypertrophy of the gallbladder wall. Unlike leiomyoma this represents a reactive process rather than a neoplastic process. However, leiomyomas and GI stromal tumors do occur in gallbladder.