A Case of IgG4-Negative Sclerosing Cholangitis and Autoimmune Pancreatitis Responsive to Steroids

Abstract

Introduction: IgG4-related disease (IRD) is a multi-organ fibroinflammatory syndrome characterized by typical histopathology, tissue infiltration with IgG4-positive cells, and elevation of serum IgG4. Manifestations of IgG4-associated systemic disease include IgG4-associated cholangitis (IAC) and autoimmune pancreatitis (AIP, type 1). Various diagnostic criteria have been suggested, combining the serologic measurement of IgG4 levels with characteristic clinical, radiologic, and histologic findings. Herein, we present a case that defied classification and thus presented a substantial diagnostic and therapeutic dilemma. Case Report: A 70-year-old male presented to the emergency department with complaints of pruritis, anorexia, weight loss, and painless jaundice. A CT of the abdomen was notable for diffuse intrahepatic biliary ductal dilatation with multiple abrupt annular strictures. MRCP revealed a 2.9-cm posterior pancreatic head mass and thus initial diagnostic concern was for pancreatic malignancy. ERCP with biliary duct dilation and stent placement was performed and a biopsy showed atypical biliary epithelium with inflammation but no evidence of malignancy. An EUS was performed and FNA specimen obtained, with histology demonstrating nonspecific chronic inflammation without IgG4 positivity by immunoperoxidase staining. Total serum IgG levels were elevated, but the IgG4 subset was within normal limits (28.8). The CA 19-9 level was 228. After excluding malignancy, the patient was empirically treated with oral prednisone 40 mg daily for 4 weeks and tapered gradually. His symptoms abated and radiologic findings of biliary duct dilatation and stricturing, as well as the pancreatic mass, resolved. At 1-year follow-up, he has been weaned off steroids and is symptom free. Discussion: IRD is an under-recognized protean disorder, mimicking many systemic conditions. Our case demonstrates the gap in current diagnostic classification of IRD. AIP and IAC should be suspected in patients with unexplained biliary strictures and pancreatic diseases regardless of serum IgG4 levels, as this finding is present in only 50-90% of patients. Evaluation for possible pancreatic and biliary malignancies should take primary precedence. However, when malignancy is excluded and features of AIP are present despite negative serologic and histologic evaluation, an empiric steroid trial is reasonable and may prove diagnostic, as AIP is nearly universally steroidresponsive.Figure 1