MULTISYSTEM IGG4-RELATED DISEASE PRESENTING WITH RECURRENT PANCREATITIS, BILIARY STRICTURE, AND SUBMANDIBULAR LYMPHADENOPATHY

Case Presentation: A 43-year-old Hispanic male with a past medical history of biliary pancreatitis status post cholecystectomy and endoscopic retrograde cholangiopancreatography (ERCP) with common bile duct (CBD) stent placement presented with abdominal pain, nausea, vomiting, and inability to tolerate oral intake. He also reported painful submandibular swelling and left eye proptosis associated with clear drainage.Laboratory findings revealed:· Lipase: 1,500 U/L· Alkaline phosphatase: 427 U/L· AST: 187 U/L· ALT: 158 U/LCT abdomen demonstrated acute pancreatitis with a contracted gallbladder, intrahepatic biliary dilatation, and a CBD stent in place without pneumobilia. He subsequently underwent ERCP, which revealed an occluded CBD stent. The stent was removed, resulting in significant improvement in oral intake and abdominal pain.Further laboratory evaluation revealed an elevated globulin gap (6.8 g/dL). Immunologic workup showed:· Total IgG: 454 mg/dL · IgG4: 3,348 mg/dL · Peripheral eosinophilia presentGiven the constellation of findings—recurrent pancreatitis, biliary stricture, submandibular and mesenteric lymphadenopathy, unilateral proptosis with clear ocular drainage, and lacrimal gland swelling—IgG4-related disease was strongly suspected.A mandibular gland biopsy revealed dense lymphoplasmacytic infiltration with scattered eosinophils and storiform fibrosis, consistent with IgG4-related sialadenitis. Hepatitis panel and T-Spot TB tests were negative.Following confirmation of the diagnosis, the patient was started on high-dose corticosteroid therapy with gradual tapering. Due to the multisystem involvement, he was subsequently treated with rituximab. Following therapy, his symptoms improved markedly: Resolution of proptosis and clear eye drainage· Decrease in submandibular lymph node enlargement· Improved biliary and pancreatic function

Discussion: This case highlights the diverse clinical presentation of IgG4-related disease and underscores the importance of considering it in patients with recurrent pancreatitis, unexplained biliary obstruction, and glandular swelling.The disease may mimic malignancy or infection and can involve the pancreas (autoimmune pancreatitis type 1), biliary tree (sclerosing cholangitis), salivary glands (sialadenitis), lacrimal glands (dacryoadenitis), and lymph nodes.Diagnosis requires a combination of:1. Elevated serum IgG4 levels (>135 mg/dL)2. Typical histopathologic findings: lymphoplasmacytic infiltrate rich in IgG4+ plasma cells, storiform fibrosis, and obliterative phlebitis3. Clinical and radiologic correlationFirst-line treatment is glucocorticoid therapy, which induces remission in most cases. Rituximab is indicated for refractory or relapsing disease. Long-term follow-up is necessary to monitor for relapses and organ dysfunction.

Conclusions: IgG4-related disease should be considered in patients with recurrent pancreatitis and biliary obstruction, particularly when accompanied by glandular swelling and orbital involvement with clear eye drainage. Early diagnosis and initiation of corticosteroid therapy can prevent irreversible organ damage and significantly improve outcomes.· IgG4-RD can present with multisystem involvement, mimicking malignancy or infection.· Elevated serum IgG4 and confirmatory tissue biopsy are essential for diagnosis.· Early corticosteroid therapy is highly effective; rituximab may be used in relapsing or refractory disease.