A Cholangioscopy-Based Novel Classification System for the Phenotypic Stratification of Dominant Bile Duct Strictures in Primary Sclerosing Cholangitis—the Edmonton Classification

Abstract

Background Primary sclerosing cholangitis (PSC) is a chronic inflammatory condition causing bile duct strictures. Differentiating inflammatory strictures from malignant transformation is challenging. Cholangioscopy allows direct visualization with the option to biopsy. We describe our experience of cholangioscopy in PSC and propose a novel stricture classification system based on cholangioscopic findings. Methods All patients with PSC and a dominant stricture referred for cholangioscopy were reviewed. Based on visual characteristics with direct cholangioscopy, we propose a novel classification system for the extrahepatic form of PSC. Results The proposed Edmonton Classification system for extrahepatic PSC strictures consists of the following phenotypes: 1) ‘inflammatory type’, with mucosal erythema and active inflammatory exudate, 2) ‘fibro-stenotic type’, with concentric fibrotic scars, and 3) ‘nodular or mass-forming type’, with a mass in the involved segment of extrahepatic bile duct. From 2011–2017, 30 patients with PSC and a dominant stricture (21 M, mean age 46 years) underwent 32 cholangioscopy procedures. Cholangioscopy was technically successful in 29 of 32 procedures (91%). In these 29 stricture cases, inflammatory type was seen in 16 (55%), fibro-stenotic type in seven (24%) and nodular or mass-forming type in five (17%). In one (4%) procedure, there was no stricture or abnormality identified. Conclusion Cholangioscopy is effective and safe for the evaluation of dominant biliary strictures in PSC. Based on our experience with cholangioscopy, we propose a novel classification system of extrahepatic PSC phenotypes: the Edmonton Classification.

The Expansion of Cholangioscopy: Established and Investigational Uses of SpyGlass in Biliary and Pancreatic Disorders

“…The study included 30 patients with PSC and a bile duct stricture and classified these patients into three phenotypes based on visual features: inflammatory type, fibro-stenotic type, or nodular mass-forming type. The phenotypes could then be used to determine a patient's risk for malignancy and help guide further management [25]. This study again shows the advantage that direct visualization can have compared to traditional ERCP techniques on patients with biliary strictures.…”

“…The authors of this study are currently working on correlating the visual findings on cholangioscopy with histopathology from biopsy. They also acknowledge that larger scale studies are needed to further develop a management algorithm that can be used in patients with PSC [25].…”

Role of Peroral Cholangioscopy in the Diagnosis of Primary Sclerosing Cholangitis

“…Sandha et al further investigated the cholangioscopic findings of PSC and stratified PSC into the following three types based on visual characteristics: (1) inflammatory, (2) fibrostenotic, and (3) nodular or mass-forming. The inflammatory type showed mucosal erythema, ulceration, and fibrinous white exudate; the fibrostenotic type showed circumferential rings and asymmetric cicatrization; and the nodular or mass-forming type showed focal nodular tissue growth [33]. Although the small numbers of patients in both studies (five [32] and 29 [33] patients) might not accurately represent the overall disease characteristics of PSC, these results suggest that the cholangioscopic findings of PSC may vary according to the disease stage.…”

Guideline review: British Society of Gastroenterology/UK-PSC guidelines for the diagnosis and management of primary sclerosing cholangitis

“…The advent of cholangioscopy has led to a better knowledge of dominant strictures. The Edmonton classification identifies three subclasses of strictures: the inflammatory type, the fibrostenotic type and the nodular or mass-forming type, which is the most concerning for evolution to cholangiocarcinoma (CCA) 8…”