Epidemiology and diagnosis for Adenomyomatosis of the Gallbladder

Abstract

Adenomyomatosis of the Gallbladder is a common benign lesion characterized by numerous branching Rokitansky-Aschoff sinuses accompanied by smooth muscle hyperplasia and an expansion of the subserosal layer. Although, adenomyomatosis is defined as the wall thickness over 3mm with 5 or more numbers of RAS within 1cm in the histopathological specimen, there is no agreed definition with imaging diagnosis. We recommend imaging diagnostic definition as "the wall thickness over 4mm with dilated RASs or intramural stones". The wall thickness should be measured by US (EUS) or enhanced CT. Microcystic area or comet-like echo as US findings, pearl necklace sign in MR images are supportive diagnostic signs for adenomyomatosis. When gallbladder cancer is suspected, the mucosal surface and the multilayer structures in the thickened wall should be evaluated by enhanced CT or EUS. Cases with abdominal symptoms, suspicious of gallbladder cancer, segmental type complicated with gallstone or hourglass deformity are indications for surgery. The cases with no symptom nor suspicious of gallbladder cancer are recommended a conservative US follow up with twice a year.