Adenomyomatosis is best described as which of the following?

• A. Hyperplasia of epithelial and muscle layers in the gallbladder wall
• B. Gallbladder adenoma
• C. Cholangiocarcinoma
• D. Porcelain gallbladder

Answer: (A)

Adenomyomatosis is a benign thickening of the gallbladder wall due to hyperplasia of the mucosal epithelium and the muscularis propria, with formation of Rokitansky-Aschoff sinuses (intramural diverticula). This combination explains the characteristic wall thickening seen on imaging and the presence of small intramural diverticula. It’s not a true neoplasm like a gallbladder adenoma, nor a bile duct cancer such as cholangiocarcinoma, and it isn’t a calcified, porcelain gallbladder. On ultrasound, you may see segmental or diffuse wall thickening with intramural diverticula and sometimes a comet-tail artifact from reverberation within the sinuses, which helps differentiate it from malignant processes.