Gallbladder adenomyomatosis: Diagnosis and management.

Gallbladder (GB) adenomyomatosis (ADM) is a benign, acquired anomaly, characterized by hypertrophy of the mucosal epithelium that invaginates into the interstices of a thickened muscularis forming so-called Rokitansky-Aschoff sinuses. There are three forms of ADM: segmental, fundal and more rarely, diffuse. Etiology and pathogenesis are not well understood but chronic inflammation of the GB is a necessary precursor. Prevalence of ADM in cholecystectomy specimens is estimated between 1% and 9% with a balanced sex ratio; the incidence increases after the age of 50. ADM, although usually asymptomatic, can manifest as abdominal pain or hepatic colic, even in the absence of associated gallstones (50% to 90% of cases). ADM can also be revealed by an attack of acalculous cholecystitis. Pre-operative diagnosis is based mainly on ultrasound (US), which identifies intra-parietal pseudo-cystic images and "comet tail" artifacts. MRI with MRI cholangiography sequences is the reference examination with characteristic "pearl necklace" images. Symptomatic ADM is an indication for cholecystectomy, which results in complete disappearance of symptoms. Asymptomatic ADM is not an indication for surgery, but the radiological diagnosis must be beyond any doubt. If there is any diagnostic doubt about the possibility of GB cancer, a cholecystectomy is justified. The discovery of ADM in a cholecystectomy specimen does not require special surveillance.