Sonographic Characteristics of ≥7 mm Gallbladder Polyps: A Retrospective Analysis

To describe the sonographic characteristics of gallbladder polyps measuring ≥7 mm focusing on echogenicity, correlate with surgical pathology when available, and assess stability in size over time.

This retrospective study used a natural language processing application to screen ultrasound (US) reports between January 1, 2012, and December 31, 2020, that contained the words "gallbladder polyp" or "polyps." Reports were reviewed to identify polyps ≥7 mm. The most hyperechoic components of the polyps were compared to the adjacent inner wall of the gallbladder and categorized as more echogenic, isoechoic, and less echogenic. Other sonographic characteristics such as heterogeneity, sessile configuration, vascularity, multiplicity, presence of gallstones, and wall thickening were recorded. Surgical pathology reports were reviewed when available. Polyps in nonsurgical patients with ≥48-month US follow-up and ≤1 mm/year growth rate were characterized as benign. Clinical outcomes were followed until December 31, 2023.

Review of 4897 reports yielded 550 reports in 450 patients with polyps ≥7 mm. Surgical pathology reports were available in 22.0% (99/450) of patients; 96 (97%) had non-neoplastic etiologies and 3 (3.0%) neoplastic. There were no malignancies. All of the neoplastic polyps and 56.1% (87/155) of non-neoplastic polyps had components more echogenic than the adjacent inner wall. There were no deaths related to the polyps.

The vast majority of gallbladder polyps are benign. In our large series of gallbladder polyps, we found that increased echogenicity is a nonspecific feature, found in slightly more than half of benign but also in all neoplastic polyps. Our findings support current Society of Radiologists in Ultrasound consensus guidelines.