Lymphoplasmacytic granuloma localized to the ampulla of Vater: an ampullary lesion of IgG4-related systemic disease?

Clinical practice guidelines for IgG4-related sclerosing cholangitis

IgG4‐related sclerosing cholangitis (IgG4‐SC) is a distinct type of cholangitis frequently associated with autoimmune pancreatitis and currently recognized as a biliary manifestation of IgG4‐related disease. Although clinical diagnostic criteria of IgG4‐SC were established in 2012, differential diagnosis from primary sclerosing cholangitis and cholangiocarcinoma is sometimes difficult. Furthermore, no practical guidelines for IgG4‐SC are available. Because the evidence level of most articles retrieved through searching the PubMed, Cochrane Library, and Igaku Chuo Zasshi databases was below C based on the systematic review evaluation system of clinical practice guidelines MINDS 2014, we developed consensus guidelines using the modified Delphi approach. Three committees (a guideline creating committee, an expert panelist committee for rating statements according to the modified Delphi method, and an evaluating committee) were organized. Eighteen clinical questions (CQs) with clinical statements were developed regarding diagnosis (14 CQs) and treatment (4 CQs). Recommendation levels for clinical statements were set using the modified Delphi approach. The guidelines explain methods for accurate diagnosis, and safe and appropriate treatment of IgG4‐SC.

Immunoglobulin G4-related gastrointestinal diseases, are they immunoglobulin G4-related diseases?

In immunoglobulin G4 (IgG4)-related disease (RD), organ enlargement or nodular lesions consisting of abundant infiltration of lymphocytes and IgG4-positive plasma cells and fibrosis are seen in various organs. Although infiltration of many IgG4-positive plasma cells is detected in the gastric and colonic mucosa and major duodenal papilla of patients with autoimmune pancreatitis, it cannot be diagnosed as a gastrointestinal lesion involved in IgG4-RD, because none of the following is observed in these lesions: a mass-like formation; dense fibrosis; or obliterative phlebitis. Based on our review of the literature, there appear to be two types of IgG4-related gastrointestinal disease. One is a gastrointestinal lesion showing marked thickening of the wall of the esophagus and stomach, consisting of dense fibrosis with abundant infiltration of IgG4-positive plasma cells, which usually show submucosal spreading. The other is an IgG4-related pseudotumor occurring in gastrointestinal regions such as the stomach, colon, and major duodenal papilla, showing polypoid or mass-like lesions. Most solitary IgG4-related gastrointestinal lesions that are not associated with other IgG4-RD appear to be difficult to diagnose. It is of utmost importance to rule out malignancy. However, these lesions may respond to steroid therapy. To avoid unnecessary resection, IgG4-related gastrointestinal diseases should be considered in the differential diagnosis.

The therapeutic strategy for autoimmune pancreatitis is subject to the endoscopic features of the duodenal papilla

Autoimmune pancreatitis (AIP) often presents with a swollen duodenal papilla, however, the clinical significance of the duodenal papilla in AIP has not been fully elucidated. Data have shown swollen duodenal papillae shaped like a pear and/or with a submucosal tumor having IgG4-bearing plasma cells. Immunohistopathology has potentially verified duodenal papillitis associated with AIP. FOXP3-positive lymphocytes are also recognized in AIP. AIP has shown spontaneous remission and relapse irrelevance to corticosteroid therapy. The results of a multivariate analysis revealed the absence of a swollen duodenal papilla as the only significant independent factor predictive of spontaneous remission in AIP cases. In addition, the results of another multivariate analysis revealed the presence of a swollen duodenal papilla and the presence of extrapancreatic lesions as the significant independent factors predictive of relapse in these cases. Results suggest that the lack of a swollen duodenal papilla is a predictive factor for spontaneous remission, and thus negates the need to administer corticosteroids in those AIP patients. In contrast, a swollen duodenal papilla and the presence of extrapancreatic lesions are risk factors for relapse, and those AIP patients are candidates for maintenance corticosteroid therapy to reduce relapse. Therefore, the therapeutic strategy such as the indication for corticosteroid administration is subject to the endoscopic features of the duodenal papilla.