Gallbladder polyps are growths that stick out from the lining of the inside of the gallbladder. They typically cause no noticeable symptoms and are often found on imaging studies done for other reasons. Polyps can be cancerous, but they rarely are. About 95% of gallbladder polyps are benign, meaning they're not cancerous.

The size of a gallbladder polyp can help predict whether it's cancerous, called malignant, or noncancerous, known as benign. Small gallbladder polyps that are less than 1/2 inch — about 10 millimeters (mm) — in diameter are unlikely to be cancerous and generally don't require treatment.

However, even for smaller polyps, follow-up examinations are recommended to look for changes that may be a sign of cancer. This is commonly done using standard abdominal ultrasound. Less commonly, it is done with an endoscopic ultrasound or a CT scan. If a gallbladder polyp increases in size by 2 mm or more, surgical removal of the gallbladder, called cholecystectomy, may be recommended.

Gallbladder polyps larger than 1/2 inch (about 10 mm) in diameter are more likely to be cancerous or turn into cancer over time. Those larger than 3/4 inch (18 mm) in diameter may pose a significant risk of being malignant. Treatment of larger gallbladder polyps includes cholecystectomy. Again, malignant polyps are extremely rare. Only about 5% of gallbladder polyps are cancerous.

A cholecystectomy may be recommended if you have a gallbladder polyp of any size along with gallstones or a polyp greater than 1/3 inch (about 8 mm). Cholecystectomy also may be recommended if you have a condition known as primary sclerosing cholangitis.