IgG4-related cholangitis (IRC) is a chronic cholestatic liver disease that often occurs concomitantly with autoimmune pancreatitis type 1. Both conditions are manifestations of IgG4-related disease, a systemic autoimmune-mediated fibroinflammatory disorder. Patients often present with jaundice and weight loss, mimicking hepatobiliary malignancies, such as cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic cancer. Accurate diagnosis is challenging due to the absence of pathognomonic findings but can be achieved using the HISORt criteria (histology, imaging, serology, other organ involvement, and response to immunosuppressive therapy). Early diagnosis is critical to avoid unnecessary surgery and prevent progression to liver fibrosis or cirrhosis. IRC responds well to corticosteroid therapy, though relapses are common, necessitating long-term immunosuppressive treatment in many cases. Steroid-sparing agents for remission induction and maintenance therapy comprise immunomodulators, such as azathioprine, as well as B-cell depletion therapies, such as rituximab. This review provides a structured clinical overview of the diagnosis, differential diagnosis, and therapy, including novel therapeutic options, such as inebilizumab, for this rare yet severe condition. A key focus is on long-term surveillance strategies, which include laboratory tests, imaging (contrast-enhanced magnetic resonance imaging/magnetic resonance cholangiopancreatography, ultrasound, endosonography), and, particularly in patients with fibrotic bile duct strictures, endoscopy (endoscopic retrograde cholangiopancreatography, cholangioscopy).

Autoimmune pancreatitis is a fibroinflammatory subtype of chronic pancreatitis resulting from aberrant immune responses. Currently, there are two forms of autoimmune pancreatitis: type 1 (T1-AIP) or lymphoplasmacytic sclerosing pancreatitis and type 2, also known as idiopathic duct-centric chronic pancreatitis. T1-AIP is often identified as the pancreatic appearance of immunoglobulin 4 (IgG4)-related disease. T1-AIP commonly appears in the seventh decade of life with a considerable male predominance, frequently associated with elevations in serum IgG4 levels and IgG4-positive cells on tissue biopsy. Type 1 and 2 autoimmune pancreatitis glucocorticoid steroid treatment leads to clinical remission in almost 100% of type 1 and 2 cases. Here, we present a case of an adult who presented with an incidental pancreatic head and tail mass on CT imaging with elevated serum IgG4 levels. He was started on steroid therapy with eventual clinical remission of his disease. This case highlights the rarity of autoimmune pancreatitis and the work-up required to rule out malignancy of the pancreatic mass.

IgG-4 related disease (IgG4-RD) is an autoimmune disease that can affect multiple organs and mimic adenocarcinoma of the pancreas. We describe the case of a 74-year-old man who presented with pancreatic mass and biliary obstruction. He was initially diagnosed with pancreatic adenocarcinoma and was started on chemotherapy. Eventually, he was diagnosed with IgG-4 related disease with autoimmune pancreatitis type 1 and IgG-4 sclerosing cholangitis with rapid improvement of symptoms and clinical findings after receiving steroid therapy.

Objective: To explore and analyze the clinical features of patients with immunoglobulin (Ig)G4-related hepatobiliary-pancreatic disease and the independent factors affecting the prognosis of IgG4-related sclerosing cholangitis (IgG4-SC). Methods: The clinical data of 179 adult cases diagnosed with IgG4-related hepato-pancreato-biliary disease in the Division of Gastroenterology and Hepatology, Renji Hospital, Shanghai Jiao Tong University School of Medicine from January 2011 to December 2022 were retrospectively analyzed. Patients were divided into three groups: isolated IgG4-SC, IgG4-SC/type 1 autoimmune pancreatitis(type 1 AIP), and isolated AIP according to the clinical manifestations. Demographic characteristics, baseline biochemical immunological indexes, and imaging manifestations were analyzed. The treatment response rate and survival rate were compared. The COX proportional hazards model was used to analyze the independent factors related to prognosis. Results: The mean age of diagnosis of patients with IgG4-related hepatobiliary-pancreatic disease was 60.3±12.0 years. Males accounted for 74.9%, and the median follow-up time was 38 months. The 1-year clinical response rate of patients with isolated IgG4-SC was lower than that of IgG4-SC/AIP (67.9% vs. 91.7%, P=0.019), and the primary endpoint-free 5-year survival rate was significantly reduced (64.9% vs. 95.9%, P<0.001). COX regression analysis showed that having cirrhosis before treatment (HR=6.708, P=0.004) and poor response after half a year of treatment (HR=11.488, P=0.002) were independent risk factors associated with the occurrence of adverse events in hepatobiliary diseases among patients with IgG4-SC. Conclusions: The clinical response rate and survival rate of patients with isolated IgG4-SC are lower than those of patients with IgG4-SC/AIP. Patients with IgG4-SC who do not respond well at six months of treatment and who have progressed to cirrhosis before treatment are at significantly increased risk of adverse events. 目的： 探索免疫球蛋白（Ig）G4相关肝胆胰疾病患者临床特征，并分析影响IgG4相关硬化性胆管炎（IgG4-SC）预后的独立因素。 方法： 回顾性分析2011年1月至2022年12月期间于上海交通大学医学院附属仁济医院消化内科确诊为IgG4相关肝胆胰疾病的179例成人患者的临床资料，根据临床表现将患者分为孤立性IgG4-SC、IgG4-SC/1型自身免疫性胰腺炎（AIP）和孤立性AIP 3组，分析其人口学特征、基线生物化学、免疫学指标与影像学表现，并对治疗应答率及生存率进行比较，采用COX比例风险模型分析与预后相关的独立因素。 结果： IgG4相关肝胆胰疾病患者平均诊断年龄为（60.3±12.0）岁，男性占比为74.9%，中位随访时长为38个月。不同于IgG4-SC/AIP，孤立性IgG4-SC患者1年临床应答率较低（67.9%比91.7%，P=0.019），且5年内免于主要终点事件生存率显著降低（64.9%比95.9%，P<0.001）。COX回归分析显示，经治疗半年时应答不佳（HR=11.488，P=0.002）及治疗前肝硬化状态（HR=6.708，P=0.004）是与IgG4-SC患者肝胆疾病不良事件发生相关的独立风险因素。 结论： 孤立性IgG4-SC患者临床应答率及生存率均低于IgG4-SC/AIP患者。治疗半年时应答不佳及治疗前已进展至肝硬化阶段的IgG4-SC患者发生不良事件的风险显著增加。.