Gallbladder polyps are often incidentally identified arising from the gallbladder wall and are either sessile or pedunculated. The majority are cholesterol polyps, which do not have malignant potential.
Approximately 10% of gallbladder polyps, however, are adenomas, which may have malignant potential. Polyps typically have homogeneously low to intermediate signal intensity on T1- and T2-weighted MR images. On T1-weighted post-gadolinium images, they show moderate homogeneous enhancement, which is most pronounced on delayed images.
Polyps can be readily distinguished from calculi regarding their gadolinium enhancement, or by location, if the polyp is located on the nondependent surface of the gallbladder wall. Symptomatic lesions, polyps larger than 1 cm, or interval increase in size are suggestive of malignancy, and in such cases, cholecystectomy is required (Kelekis and Semelka 1996).