Contemporary diagnosis and management of gallbladder polyps

Abstract

Gallbladder (GB) polyps are present in 5%–10% of the general population and consist of true neoplastic polyps (adenomas) and pseudopolyps (predominantly cholesterol, inflammatory, hyperplastic, focal adenomyomatosis). True polyps, although relatively rare neoplastic lesions (0.5%) are considered an important factor in malignant transformation and cancer development (5%) when their size is ≥ 1 cm. Given that it is essential to diagnose GB adenocarcinoma at an early stage to optimize therapeutic management, controversy exists about whether cholecystectomy is always necessary. Their imaging characteristics, size ≥ 1 cm, age > 50 years and genetic predisposition determine the indications for immediate cholecystectomy. In younger patients with polyps < 1 cm in size and without a familial history of GB carcinoma, imaging follow-up by ultrasound (US) seems to be a reasonable recommended policy. A scoring system by multivariate analysis (cross-sectional area > 123 mm2, positive blood flow signal, age > 55.5 years, alanine aminotransferase (ALT) levels > 50 U/L and an ALT/AST (aspartate aminotransferase) ratio > 0.77) can accurately predict true polyps. The widely accepted size threshold for US follow-up is 7 mm, and for intervention, it is 10 mm. Computed tomography or better magnetic resonance imaging can overcome any misdiagnosis of conventional US incidental findings alone that may lead to potentially unnecessary operations. In challenging cases, high-resolution US, novel three-dimensional US, endoscopic US or contrast-enhanced endoscopic US could be helpful. Novel microflow imaging can safely predict polyps. Risk factors for malignancy include age > 60 years, large gallstones, primary sclerosing cholangitis, Asian ethnicity and sessile polyps accompanied by focal gallbladder wall thickening > 4 mm. For polyps sized 6–9 mm, the absence of growth at recommended follow-up (6 months, one year, and two years) indicates treatment discontinuation; however, it is not required for size < 5 mm without risk factors. In addition to laparoscopic cholecystectomy, the standard management, novel interventional modalities preserving the GB in selected cases include per-oral transmural endoscopic resection of GB polyps after a bridge of endoscopic US-guided cholecystostomy or laparoscopic gallbladder-preserving polypectomy. Generally, there are still no precise and strong evidence-based guidelines; thus, the management policy of GB polyps should be individualized in ambiguous cases.