Gallbladder polyps can easily be confused with stones, but there are two key differences to help you distinguish them. First, polyps are soft tissue masses, so they will not cause the shadowing that is typically seen with stones. Second, polyps are adherent to the wall of the gallbladder and will not be mobile if you have the patient change position. The position of polyps can be important as they can cause acute cholecystitis if they are lodged in the neck of the gallbladder.
The vast majority of polyps seen on the US are benign, so we shouldn’t frighten our patients, but it’s important that we arrange appropriate outpatient follow-up for radiology performed ultrasound imaging to formally characterize the polyp. In a recent study, of patients with biopsied polyps seen on ultrasound, significant predictors of malignancy included age >52, presence of associated gallstones, polyp size >9mm, evidence of liver invasion, or wall thickening.