IgG4-Related Autoimmune Pancreatitis Presenting With Multiple Extrapancreatic Manifestations

Abstract

Introduction: A 43-year-old male presented with a 1-year history of an asymptomatic left inguinal mass. CT scan demonstrated a 5.3-cm well-circumscribed round heterogeneous mass in the left inguinal region, but also demonstrated a conglomerate nodal 13-cm mass surrounding the infrarenal aorta and proximal common iliac arteries, as well as pulmonary micronodules. Excisional biopsy of the inguinal mass demonstrated a benign reactive lymph node. One year later, the patient presented with an acute onset of epigastric abdominal pain and obstructive jaundice. His labs demonstrated an elevated total bilirubin of 5.6 mg/dL, alkaline phosphatase of 210 IU/mL, and ALT of 504 IU/mL, with normal previous values 3 months prior. Serum lipase was 70 units/L. MRI demonstrated a diffusely enlarged pancreas. There was also intra- and extrahepatic biliary ductal dilatation to 10 mm and mucosal enhancement of the bile duct and gallbladder. His symptoms did improve on antibiotics. His serum IgG4 eventually returned at 851 mg/dL with the remainder of IgG subclasses being normal. One month later, he was readmitted for recurrent painless jaundice. Labs demonstrated a serum total bilirubin of 14.7 mg/dL, alkaline phosphatase of 698, AST of 120, and ALT of 224. CT demonstrated worsened diffuse bile duct dilatation to 2.4 cm and complete effacement of the common bile duct at the pancreatic head with distal decompression. The pancreas was also persistently enlarged. The patient was started on prednisone 40 mg once daily. One week later, endoscopic ultrasound demonstrated heterogeneous pancreatic parenchyma with findings consistent with chronic pancreatitis with no focal pancreatic mass. The bile duct dilation improved to 12.5 mm. ERCP demonstrated a smooth stricture in the distal common bile duct with no filling defects. A sphincterotomy was performed and a plastic stent was placed. Fine needle aspiration of the pancreas was nondiagnostic. On follow-up 3 weeks later, the patient’s jaundice and laboratory abnormalities completely resolved. A serum IgG4 and repeat imaging have been ordered and are currently pending. His corticosteroid dose was tapered. This case illustrates interesting findings of type 1 IgG4-related autoimmune pancreatitis along with extra-pancreatic involvement consisting of IgG4-related autoimmune cholangitis, periaortitis, pulmonary nodules, and inguinal lymphadenopathy, and hence his clinical picture meets 4 out of the 5 Mayo Clinic “HISORt criteria.” With corticosteroids, his symptoms of pancreatitis and cholestasis did resolve, as did his laboratory abnormalities. Follow-up imaging and serum IgG4 is currently pending and will be available to report by the time of presentation of this clinical vignette.