Prevalence of Gallbladder Polyps
Gallbladder polyps are found in approximately 5-6% of adults undergoing abdominal ultrasonography, making them a relatively common incidental finding. 1, 2
Epidemiologic Data
The prevalence of gallbladder polyps varies across studies based on population characteristics and imaging techniques:
- Most studies report prevalence between 0.3% and 12.3% in adult populations, with the majority clustering around 5-6% 1, 3, 4, 5
- In a large 20-year cohort study of 622,227 adults, gallbladder polyps were detected in 5.8% (35,870 patients) who underwent abdominal ultrasonography 2
- The variation in reported prevalence (ranging from 1.3% to 9.5%) reflects differences in study populations, imaging quality, and detection thresholds 3, 4
Clinical Context and Significance
The vast majority of detected polyps are benign and clinically insignificant:
- Only 6% of all gallbladder polyps are truly neoplastic (pyloric gland adenomas or intracholecystic papillary neoplasms) 6, 7
- Approximately 60-70% are cholesterol polyps, which are nonneoplastic pseudopolyps with negligible malignancy risk 7, 3
- Most sonographically identified polyps are under 10 mm and do not require surgical intervention 6
Size Distribution
The size distribution of detected polyps is heavily skewed toward smaller lesions:
- The majority of polyps measure less than 6 mm at initial detection (17,531 of 35,856 patients in one large cohort) 2
- Only 5.7% of detected polyps measure 10 mm or larger (2,055 of 35,856 patients) 2
- Polyps between 6-10 mm represent an intermediate group requiring risk stratification 6
Detection Bias and Clinical Implications
The increasing prevalence of detected gallbladder polyps reflects improved imaging technology and increased health screening rather than true disease increase 3:
- Most patients with gallbladder polyps are completely asymptomatic, with polyps discovered incidentally during imaging for unrelated conditions 1
- Up to 61-69% of polyps seen on ultrasound are not identified at subsequent cholecystectomy, suggesting many represent imaging artifacts or transient findings 6
- For apparent polyps of 5 mm or smaller, no polyp is found at cholecystectomy in up to 83% of cases 6
Geographic and Ethnic Variations
While gallbladder cancer shows significant geographic variation (highest in Indigenous North and South American populations and North Indian populations), it is unclear whether increased cancer risk correlates with increased polyp incidence 6