IgG4-Related Sclerosing Cholangitis with Cholecystitis Mimicking Cholangiocarcinoma: A Case Report.

IgG4-related diseases are rare multisystem disorders involving salivary glands, retroperitoneum, pancreas, biliary tract, and liver. Isolated biliary strictures and gall bladder involvement are rare in such patients, and presentation with cholangitis and weight loss can misguide the diagnosis toward malignancy. Here, we report an interesting case of IgG4-related biliary stricture with gall bladder involvement, presented with cholangitis and weight loss. The initial symptoms and imaging were guided toward the malignant possibilities of cholangiocarcinoma and pancreatic carcinoma. However, endosonography, serology, and histopathology clinched the diagnosis of IgG4-related disease. The patient was managed without any biliary intervention and with antibiotics, steroids, and steroid-sparing agents. There was a relapse of disease during the steroids taper that improved after hiking its doses. The disease responded with medical management on follow-up. We demonstrated the effectiveness of steroid-sparing agents to treat IgG4-related diseases, especially to avert the steroid-related adverse effects. This case highlights the possible mislead for the diagnosis and delayed management of IgG4 disease due to shared clinical features with hepatobiliary malignancies and the effectiveness of noninvasive measures of management.