Because IAC can manifest as a pseudotumourous mass or diffuse sclerosing cholangitis, the most important differential diagnosis of IAC should include CCA and primary sclerosing cholangitis (PSC), while the Epacadostat former had more chances of misdiagnosis than any other disease.[2-7, 12] Based on characteristics of IAC and the current situation of high incidence with misdiagnosis of IAC, the correct diagnosis of IAC becomes a challenge for clinicians. The aim of this review is clarify the concept of IAC,
summarizing the criteria for diagnosis of IAC, discuss the role of CA 19-9, and provide key information for differential diagnosis of IAC from CCA, which might provide insight into the disease and be helpful to clinical work. Immunoglobulin G4-associated cholangitis is a part of IgG4-related sclerosing disease (ISD), which is recognized based on studies of autoimmune pancreatitis (AIP). In 1961, Sarles et al. first suggested that chronic inflammatory sclerosis of the pancreas might be an autonomous pancreatic disease. Later, in 1995, the concept of AIP was proposed by Yoshida et al. Since then many cases have been reported, and AIP has become a distinct entity recognized worldwide. Based on histological and immunohistochemical find more examination
of various organs of patients with AIP showing abundant IgG4 positive cells that distinguish AIP from alcoholic pancreatitis and inflammatory infiltrate surrounding pancreatic cancer, ISD was proposed as a novel clinicopathological entity by Kamisawa et al. in 2003. IgG4-related sclerosing disease is a systemic disease and responds to steroid MCE therapy. Its characteristic is abundant IgG4-positive plasma cells infiltrate in various organs or tissues, such as the pancreas, extrahepatic bile duct wall, salivary glands, retroperitoneal tissue, etc., resulting in pancreatitis, cholangitis, sialadenitis, and retroperitoneal fibrosis, respectively. At present, the clinicopathological
findings of ISD are listed in Table 1. ISD could clinically involve one or two or more than three organs or tissues, causing a systemic effect, and therefore, the clinical presentation is complex, mainly according to the organs involved. Immunoglobulin G4-associated cholangitis is a part of and is relatively common in multi-organ ISD. Since steroid responsiveness is its most distinguishing clinical feature, IAC may be defined as a biliary stricture that responds to or improves with steroid therapy, frequently associated with other fibrosing conditions, especially AIP. It is characterized by elevation of IgG4 in serum and infiltration of IgG4 positive plasma cells in bile ducts.[21-23] According to the Ghazale et al. report, the largest number of cases studied was 53 IAC patients. They state that IAC should be suspected in unexplained biliary strictures associated with increased serum IgG4 and unexplained pancreatic disease. The clinical IAC patients were generally older (mean age 62 years), although young patient age was reported.