In patients with gallbladder polyps, it is important to note what type of polyp is described. While true polyps are adenomatous, gallbladder polyps are often non-epithelial growths and, in fact, about 70% of polyps are cholesterol polyps that have no malignant potential. Adenomas are uncommon and constitute approximately 8% of all gallbladder polyps. Less common polypoid lesions include gallbladder adenocarcinomas, inflammatory polyps, gallstones masquerading as polyps and heterotopic tissue.

Morphology and size have long been deemed important features of gallbladder polyps.

A ten millimeter rule for gallbladder polyps is often cited as a reason for cholecystectomy because polyps larger than 10 mm have an increased risk of cancer. Several caveats should be kept in mind when considering the size and morphology of gallbladder polyps.

• Polyps less than 5 mm rarely, if ever, harbor carcinoma.

• Polyps greater than 15 mm may have cancer cells in up to 70% of specimens.

• Polyps that are 5-15 mm must be carefully followed; with a risk of malignancy up to 22% in these patients. Finally, sessile polyps are more likely malignant than pedunculated polyps.