Pearl necklace sign

Adenomyomatosis of the gallbladder is a hyperplastic cholesterolosis of the gallbladder wall which is common and benign.
Adenomyomatosis presents usually asymptomatic, however in most cases It is associated with chronic biliary inflammation, most commonly gallstones in 25 - 75% but also seen in cholesterolosis in 33% and pancreatitis.

The pearl necklace sign is seen in patients with adenomyomatosis of the gallbladder, on both oral cholecystograms and MRCP. It represents the contrast / fluid filled intramural mucosal diverticula (Rokitansky-Aschoff sinuses) which line up reminiscent of pearls on a necklace.

MRI images demonstrate adenomyomatosis at the gallbladder fundus This case was donated to Radiopaedia.org by Radswiki.net

It is said to be highly specific (92%) for the diagnosis of adenomyomatosis, however is frequently not seen, only present in ~70% of cases.