Abstract
Polypoid gallbladder lesions include various histologic types, such as adenocarcinomas, adenomas, hyperplasia, cholesterol polyps, inflammatory polyps, and adenomyomatosis. We describe current status of imaging findings in diagnosis of these polypoid lesions. In cholesterol polyps and adenomyomatosis of the gallbladder, typical imaging findings usually are observed by ultrasonography, endoscopic ultrasonography including color Doppler, computed tomography, and magnetic resonance imaging (MRI). Cholesterol polyps appear as pedunculated polyps with hyperechoic spots by ultrasonography. Adenomyomatosis of the gallbladder shows comet-like echo patterns, with an echo-free area within the lesion. However, cholesterol polyps exceeding 10 mm in diameter with a solid internal echo pattern and adenomyomatosis with no echo-free area are difficult to distinguish from adenocarcinoma. As the size of a polypoid lesion increases, so does the likelihood of carcinoma. Accordingly, cholecystectomy should be considered for polypoid lesions larger than 10 mm without typical cholesterol polyp or adenomyomatosis findings on imaging. Recently, diffusion-weighted MRI, contrast-enhanced ultrasonography, and contrast-enhanced endoscopic ultrasonography have been reported to be useful in differential diagnosis. Further improvements of diagnostic modalities are expected. Department of Gastroenterology, Second Teaching Hospital, Fujita Health University, Japan
