Gallbladder Polyps as Precursors of Gallbladder Carcinoma: A Narrative Review for Clinical Practice.

BACKGROUND: Gallbladder carcinoma is an uncommon but highly lethal malignancy that is frequently diagnosed at an advanced stage. Among proposed precursor lesions, true neoplastic gallbladder polyps (particularly adenomas and intracholecystic papillary neoplasms) have received increasing attention as potential steps in an adenoma-carcinoma sequence, analogous to colorectal tumorigenesis [CA Cancer J Clin. 2021;71(3):209-49, Br J Radiol. 2022;95(1137):20220152, Eur Radiol. 2022;32(5):3358-68, and Radiology. 2022;305(2):277-89]. However, most gallbladder polyps detected on imaging are benign, and the absolute cancer risk in incidentally detected polyps remains low [CA Cancer J Clin. 2021;71(3):209-49, Br J Radiol. 2022;95(1137):20220152, Radiology. 2022;305(2):277-89, JAMA Netw Open. 2020;3(5):e205143, and Abdom Radiol. 2024;49(9):3158-65]. SUMMARY: Gallbladder polyps are identified in roughly 3-7% of adults undergoing abdominal ultrasonography, with the majority representing non-neoplastic cholesterol or inflammatory lesions [Br J Radiol. 2022;95(1137):20220152, Radiology. 2022;305(2):277-89, JAMA Netw Open. 2020;3(5):e205143, and Chin Med J. 2024;137(14):1674-83]. Only a minority are adenomatous or preinvasive neoplasms with malignant potential [Br J Radiol. 2022;95(1137):20220152, Chin Med J. 2024;137(14):1674-83, and Am J Surg Pathol. 2012;36(9):1279-301]. Across surgical and imaging series, size is the most consistently validated risk factor for neoplasia, with thresholds around 10 mm widely adopted in guidelines as an indication for cholecystectomy in otherwise low-risk patients [Br J Radiol. 2022;95(1137):20220152, Eur Radiol. 2022;32(5):3358-68, Radiology. 2022;305(2):277-89, Abdom Radiol. 2024;49(9):3158-65, and Am J Roentgenol. 2024;222(5):e2330720]. Additional factors associated with neoplastic histology and gallbladder carcinoma include sessile morphology, older age, primary sclerosing cholangitis, Asian ethnicity, and interval growth during surveillance [Eur Radiol. 2022;32(5):3358-68, Radiology. 2022;305(2):277-89, Abdom Radiol. 2024;49(9):3158-65, Am J Roentgenol. 2024;222(5):e2330720, Korean J Gastroenterol. 2023;81(5):197-202, and Diagnostics. 2024;14(4):374]. Contemporary European joint guidelines and other international society statements advocate a risk-stratified algorithm that combines polyp size, morphology, and clinical risk factors to guide decisions between cholecystectomy, ultrasonographic follow-up, or discharge [Eur Radiol. 2022;32(5):3358-68, Radiology. 2022;305(2):277-89, Abdom Radiol. 2024;49(9):3158-65, and Am J Roentgenol. 2024;222(5):e2330720]. KEY MESSAGES: Most incidentally detected gallbladder polyps are benign and will never progress to cancer; only a small fraction are true neoplastic precursor lesions [Br J Radiol. 2022;95(1137):20220152, Eur Radiol. 2022;32(5):3358-68, JAMA Netw Open. 2020;3(5):e205143, Korean J Gastroenterol. 2023;81(5):197-202, and Diagnostics. 2024;14(4):374]. Polyps measuring at least 10 mm, sessile morphology, older age, primary sclerosing cholangitis, and certain high-risk clinical backgrounds are associated with increased malignant potential, whereas the absolute cancer risk in polyps smaller than 10 mm is very low in large cohort and meta-analytic data [Br J Radiol. 2022;95(1137):20220152, Eur Radiol. 2022;32(5):3358-68, JAMA Netw Open. 2020;3(5):e205143, Korean J Gastroenterol. 2023;81(5):197-202, and Diagnostics. 2024;14(4):374]. Updated international guidance, therefore, supports a selective, size- and risk factor-based approach to surgery and follow-up rather than universal surveillance or prophylactic cholecystectomy [Eur Radiol. 2022;32(5):3358-68, Radiology. 2022;305(2):277-89, Abdom Radiol. 2024;49(9):3158-65, and Am J Roentgenol. 2024;222(5):e2330720].