Complications and diagnostic difficulties arising from biliary self-expanding metal stent insertion before definitive histological diagnosis

Background: Self-expanding metal bile duct stents provide good palliation for inoperable malignant disease. However, problems may arise if metal stents are inserted before definitive histological diagnosis. The aim of this study was to evaluate the outcome of such patients. Methods: A retrospective case note review was conducted of patients referred to a tertiary pancreaticobiliary center between 1992 and 2004 in whom a metal bile duct stent was inserted for presumed unresectable malignant disease before definitive histological diagnosis. Results: There were 21 patients identified. Final diagnoses were: group 1, benign disease (n = 3); group 2, resectable malignancy (n = 2); group 3, unresectable malignancy (n = 12); and group 4, diagnosis remains uncertain (n = 4). During a follow-up of 22, 38 and 111 months, the patients in group 1 had one, eight and five episodes of stent occlusion. In group 2, both patients underwent pancreaticoduodenectomy for ampullary carcinoma, 2 and 6 months after presentation. In group 3, the median time to a confirmed malignant diagnosis was 2 months (range 1-27 months). In group 4, a median of two biopsies (range 1-4) were negative for malignancy, during a median follow up of 13 months (range 3-46). Overall in eight patients, the metal stents caused artifacts on computed tomography and/or were associated with tissue in-growth making the differentiation between benign and malignant disease difficult. Conclusion: These cases indicate that metal bile duct stent insertion before definitive histological diagnosis can be problematic. A proportion of cases will have benign strictures and in others the confirmation of malignancy may be made more difficult.