Biliary brush cytology in the assessment of biliary strictures at a tertiary center in Iran

Background: Confirmation of cholangiocarcinoma and other malignant bile duct stenosis is challenging. The aim of the current study was to assess the accuracy of brush cytology for diagnosis of malignant biliary strictures. Methods: 105 patients with hepatic biliary strictures undergoing ERCP were included in this study. Prospectively collected data included symptoms, results of biochemical testing and imaging procedures, as well as details of ERCP. Exclusion criteria were: 1) strictures that would not permit passage of guidewire and brush accession; and 2) post-operative strictures. Brushings of the bile duct strictures were performed. All patients were followed for at least 6 months. The final diagnosis was confirmed following surgery, histopathological diagnosis of the lesion, radiological infiltration of adjacent organs or metastases, or after at least a 6-month follow-up. Results: 88 brush samples from 88 patients were of appropriate quality. The overall diagnostic sensitivity and specificity for malignant nature of biliary strictures were 40.7% and 100%, respectively. The sensitivity was 66.6 % for ampullary carcinomas, 36.3% for pancreatic cancer and 32.5% for cholangiocarcinomas. Conclusions: Despite the low sensitivity, due to the relative ease and safety, brush cytology should remain the first choice for diagnosis of causes of biliary strictures.