Figure 4.

Lack of typical histological findings for AIP. Immunohistochemical staining of the EUS-FNB sample in high magnification showed no IgG4-positive plasma cells (A). IgG staining was a control to show background staining (B). Storiform fibrosis was not detected with HE staining (C). EM staining showed non-specific fibrosis, but no obliterative phlebitis was detected (D). AIP: autoimmune pancreatitis, EUS: endoscopic ultrasonography, FNB: fine-needle biopsy, IgG4: immunoglobulin G4, HE: Hematoxylin and Eosin staining, EM: elastica-Masson