IgG4 related autoimmune pancreatitis and sclerosing cholangitis

Characteristics of mass-forming autoimmune pancreatitis commonly misdiagnosed as a malignant tumor

Objective

This study aimed to explore the clinical characteristics and differential diagnosis of patients with autoimmune pancreatitis (AIP) and pancreatic cancer to prevent misdiagnosis and mistreatment.

Methods

The clinical data of patients with AIP with suspected pancreatic or bile duct malignancy and pancreatic cancer were retrospectively analyzed. The risk factors and the diagnostic value of IgG4 and Tbil levels before treatment for AIP was investigated. Moreover, the imaging features and response to hormone therapy were analyzed.

Results

AIP was commonly observed in men. Compared to patients with pancreatic cancer, the incidence of poor appetite and weight loss and carbohydrate antigen 19-9 (CA19-9) level was lower in patients with AIP, while the immunoglobulin G4 (IgG4) level was higher (p < 0.05). After treatment, the IgG4 and CA19-9 levels in patients with AIP were decreased (p < 0.001). IgG4 level before treatment (OR = 2.452, 95%CI: 1.180-5.096, P = 0.016) and total bilirubin (Tbil) level before treatment (OR = 0.992, 95%CI: 0.985-0.998, P = 0.013) were independent risk factors of AIP. Furthermore, the diagnostic value of IgG4 level before treatment, Tbil level before treatment, IgG4/Tbil before treatment, and a combination of these indicators was high. Moreover, 15 (68.18%) patients with AIP had space-occupying lesions of the pancreas, and 16 (72.73%) had autoimmune cholangitis. Most patients with AIP were sensitive to hormone therapy.

Conclusions

The Tbil and IgG4 levels, imaging findings, and hormone therapy reactivity could differentiate AIP from pancreatic cancer. A combination of IgG4, Tbil, and IgG4/Tbil before treatment might be a promising diagnostic biomarker for AIP.

[IgG4-associated sclerosing cholangitis mimicking cholangiocellular carcinoma]

The paper presents an update on the epidemiology, main clinical manifestations, and diagnostic methods in IgG₄-associated sclerosing cholangitis. It highlights the importance of morphological and immunohistochemical studies in the diagnosis of the disease. It describes a case of diagnosing IgG₄-associated sclerosing cholangitis when examining the surgical material from a patient with suspected cholangiocellular carcinoma of the hepatic hilus.

A Curious Case of Autoimmune Pancreatitis with IgG4-related Sclerosing Cholangitis

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is a novel entity that belongs to the immune-mediated fibroinflammatory class of IgG4-related diseases (IgG4-RD). IgG4-SC is noted to be one of the most frequent manifestations of extra-pancreatic disease among IgG4-RD, which is significantly different from primary SC (PSC) and cholangiocarcinoma (CC) as is evident in the varied approaches to treatment. IgG4-RD includes IgG4-SC and autoimmune pancreatitis (AIP).

Herein, we presented a case of IgG4-SC in a patient with obstructive jaundice secondary to AIP. We have also discussed the current recommendations for diagnostic and treatment modalities, with an emphasis on the issues that arise in obtaining a definitive classification of disease.