Prevalence and Sonographic Detection of Gallbladder Polyps in a Western European Population

Gallbladder cancer is rare but associated with significant morbidity and mortality necessitating the early identification of premalignant and malignant lesions to improve overall prognosis. Despite limited evidence regarding the effectiveness of transabdominal ultrasound (US) in the detection of gallbladder polyps, it plays a key role in current European guidelines. The aim of this study was to investigate gallbladder polyp prevalence in a western European population and assess the diagnostic accuracy of transabdominal US.

Data from patients who underwent cholecystectomy for US detected gallbladder polypoid lesions at four hospitals in Ireland and the United Kingdom between 2010 and 2018 were retrospectively collected. Patient demographics, ultrasonographic, and histopathologic findings were analyzed.

A total of 134 patients underwent cholecystectomy for US-detected gallbladder polyps. After histopathologic examination, pseudopolyps were found in 75 (56%) specimens with dysplastic or malignant polyps seen in only six (4.5%) specimens. Mean size for neoplastic polyps was 33 mm. The positive predictive value for US in detecting neoplastic polyps in this study was 4.5%, which is significantly lower than the 10%-15% reported previously.

Although the prevalence of neoplastic polyps in this study is higher than in the previous literature, the distribution of pseudopolyps and true polyps is as expected. With all malignant polyps being >10 mm in diameter, these findings support the current size thresholds stated in European guidelines. The poor diagnostic accuracy of US demonstrated may have led to significant number of patients undergoing unnecessary surgical intervention, further supporting the argument for improved strategies for the investigation of gallbladder polyps.