P-BN21 Diagnostic accuracy of transabdominal ultrasound for assessing gallbladder polyps

Abstract

Abstract Background Gallbladder polyps are common findings on transabdominal ultrasound (TAUS) and their implications are not entirely clear. Current guidelines advise monitoring with serial TAUS and to offer laparoscopic cholecystectomy if criteria are met to minimise risk of malignant transformation. TAUS is easily accessible and useful at identifying gallbladder polyps, however, has limitations when differentiating between pseudopolyps and true gallbladder polyps with malignant potential. This study looks at a district general hospital’s outcomes for patients undergoing laparoscopic cholecystectomy for gallbladder polyps. Methods This retrospective study identified patients who had polyps identified on TAUS and subsequently undergone laparoscopic cholecystectomy from 2011 to 2021. We identified patients using hospital coding and subsequently assessed their pre-operative imaging and clinic letters to ensure gallbladder polyps were the reason for cholecystectomy. The size of polyp on TAUS was noted and pathology reports were assessed to determine if polyps had been correctly identified on TAUS and if these were true or pseudopolyps. Clinic letters were assessed to determine if patients were symptomatic pre-operatively. Results 66 patients were identified as having polyps pre-operatively. The size of polyp ranged from 2-19mm with a mean of 7.4mm. 39 (59%) patients were symptomatic pre-operatively. TAUS findings correlated with pathology findings of polyps in 45 (68%) patients. Of the 21 patients with no polyps on pathology: 11 had gallstones, 9 had chronic cholecystitis and 1 normal gallbladder. Of the polyps identified 44 were pseudopolyps and only 1 was a true adenoma – 39 cholesterol polyps, 3 inflammatory polyps and 2 adenomyomatosis. There was no evidence of dysplasia on the adenoma, it measured 5mm on TAUS and the patient was symptomatic. Conclusions This study highlights the limitations of TAUS in correctly identifying true polyps. The 41% of asymptomatic patients all had benign findings on pathology and likely had no benefit from surgery. Whilst TAUS is a useful method of identifying potential polyps these findings would suggest that other methods of identifying true polyps should be sought to minimise patients undergoing unnecessary surgery.