Indeterminate Biliary Strictures: A Retrospective Study

Background/Objectives: Diagnosing biliary obstructions is challenging, especially when histopathology is inconclusive. Non-malignant biliary strictures often require additional tests and a personalized approach. This study investigates the prevalence, characteristics, and natural history of indeterminate biliary strictures. Methods: A retrospective analysis was conducted on 510 treatment-naive patients with hyperbilirubinemia due to biliary strictures or obstruction, who were all candidates for endoscopic retrograde cholangiopancreatography (ERCP). Patients with a known etiology before the procedure were excluded. Diagnosis was made via brush cytology or intraductal biopsy during ERCP, with follow-up for indeterminate cases. Statistical analysis was performed with Statistica software (version 13.3; TIBCO Software Inc. (2017), Palo Alto, CA, USA). Results: Out of 510 patients, 186 (36.5%) had non-malignant biliary strictures. Strictures were located in the liver hilum (29.6%), common bile duct (11.8%), and peripancreatic ducts (58.1%). Follow-up ERCP identified malignancy in 21.5% of cases initially deemed benign. Non-malignant causes were confirmed in 41.4% of initially benign strictures, while 37.1% remained indeterminate. After six months, 25.8% of cases remained unresolved. Conclusions: A quarter of benign biliary strictures remain indeterminate despite follow-up, and 20% are later identified as malignant. Improved diagnostic protocols are needed to better manage and expedite the diagnosis of indeterminate biliary strictures.