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

Background: Differentiating 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.

Objective: Our 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.

Design: Case series.

Setting: Retrospective.

Patients: Twenty-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.

Interventions: ERCP, biopsy specimen taken from duodenal papilla.

Main Outcome Measurements: The presence of a swollen duodenal papilla with IgG4-positive plasma cells was useful for discriminating SC-AIP from with PSC.

Results: A 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.

Limitation: Single-center study.

Conclusions: Characteristic 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.