Differentiating sclerosing cholangitis caused by autoimmune pancreatitis and primary sclerosing cholangitis according to endoscopic duodenal papillary features

BackgroundDifferentiating primary sclerosing cholangitis (PSC) and sclerosing cholangitis caused by autoimmune pancreatitis (SC-AIP) is often challenging. Recently, endoscopic findings of the duodenal papilla in cases with AIP or PSC were reported by Unno and Parlak, although the endoscopic differentiation of these 2 conditions has not yet been fully clarified.ObjectiveOur purpose was to clarify the endoscopic findings of the duodenal papilla in patients with SC-AIP and those with PSC and to determine criteria for the differentiation of these conditions.DesignCase series.SettingRetrospective.PatientsTwenty-seven patients with SC-AIP and 12 patients with PSC who had undergone ERCP were identified from our database. We reviewed these records to determine whether the duodenal papillary findings (swollen papilla/normal papilla/small papilla) might be potentially useful for differentiating SC-AIP and PSC. Immunohistopathological findings for the duodenal papilla were also examined by using immunoglobulin G4 (IgG4) among the infiltrating plasma cells.InterventionsERCP, biopsy specimen taken from duodenal papilla.Main Outcome MeasurementsThe presence of a swollen duodenal papilla with IgG4-positive plasma cells was useful for discriminating SC-AIP from with PSC.ResultsA swollen duodenal papilla was observed in 63% (17/27) of the patients with SC-AIP, whereas there was no swelling of the duodenal papilla of the patients with PSC. A small papilla was recognized in 50% (6/12) of the patients with PSC. IgG4-positive plasma cells in the duodenal papilla were significantly detected in the patients with SC-AIP but not in the patients with PSC.LimitationSingle-center study.ConclusionsCharacteristic duodenal endoscopic papillary features in patients with SC-AIP, such as a swollen duodenal papilla and positive immunostaining for IgG4, might be helpful for discriminating this condition from PSC.