Clinical features of isolated proximal‐type IgG4‐related sclerosing cholangitis

Abstract

Background and aims

IgG4‐related sclerosing cholangitis (IgG4‐SC) presents as isolated proximal‐type sclerosing cholangitis (i‐SC). This study sought to clarify the imaging differences between i‐SC and Klatskin tumor. The differences between i‐SC and IgG4‐SC associated with autoimmune pancreatitis (AIP‐SC) were also studied.

Methods

Differentiating factors between i‐SC and Klatskin tumor were studied. The serum IgG4 level, CA19‐9 level, CT findings, cholangiography findings (symmetrical smooth long stricture extending into upper bile duct [SSLS]), endosonographic features (continuous symmetric mucosal lesion to the hilar part [CSML]), endoscopic biopsy results, treatment, relapse, and survival were also compared between patients with i‐SC and those with AIP‐SC.

Results

For a differential diagnosis between i‐SC (N = 9) and Klatskin tumor (N = 47), the cutoff value of serum IgG4 level was 150mg/dL (sensitivity=0.857, specificity=0.966). Logistic regression analysis indicated that serum IgG4 level, the presence of SSLS, presence of CSML and the presence of ampulla swollen are independent factor for identifying i‐SC. The relapse rate was significantly higher in the IgG4‐SC with AIP group than in the i‐SC group (log rank, p = 0.046).

Conclusion

i‐SC presents as a nodular lesion with SSLS and/or CSML mimicking a Klatskin tumor. Those endoscopic features might provide a diagnostic clue for i‐SC. i‐SC is likely to have a more favorable prognosis than IgG4‐SC with AIP.

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