A case of synchronous IgG4-associated pleuritis and type 1 autoimmune pancreatitis

A 50-year-old man presented to the emergency department with left chest pain, epigastralgia, and low-grade fever for several days. A CT scan showed left pleural effusion, ground-glass opacities in the lower lobes of both lungs, and a capsule-like rim in the pancreas. ERCP showed narrowing of the main pancreatic duct. EUS-FNA was performed, but pathological findings showed no IgG4-positive cells. A thoracoscopic biopsy was performed, and pathological findings showed many IgG4-positive cells. A diagnosis of autoimmune pancreatitis and IgG4-associated pleurisy was made according to international diagnostic criteria. After that, oral steroid therapy was started, and left pleural effusion and pancreatic enlargement improved.