IgG4-related Disease Presenting as a Pancreatic Mass and Bilateral Lacrimal Gland Swelling.

IgG4-related disease is characterized by multi-system inflammation and possible elevation in serum immunoglobulin-G4 level. Treatment regimens include glucocorticoids, disease-modifying anti-rheumatic agents and recently, rituximab infusions have been reported to be effective in treatment-refractory disease. We present a case of a 64-year-old male presenting with acute abdominal pain and scleral icterus. An abdominal ultrasound demonstrated extensive biliary ductal dilatation. A computed tomography (CT) scan and a magnetic resonance cholangiopancreatography (MRCP) revealed a 4.8 cm pancreatic head mass. He underwent an exploratory laparotomy, and a pathologic examination of the mass revealed a dense lymphoplasmacytic infiltrate. The patient's IgG subclass 2 level was elevated. A review of the patient's medical records revealed that, in 1992, he presented with bilateral periorbital discomfort not severe enough to require intervention. In 2006, he presented with bilateral periorbital swelling and discomfort. A magnetic resonance imaging (MRI) scan showed gross enlargement of the lacrimal glands, and a biopsy revealed a dense lymphoplasmacytic infiltrate. He was treated with corticosteroids, cyclosporine and methotrexate. The regimen was repeated in 2009 for recurrent symptoms. Hence, on our encounter, a diagnosis of IgG4-related disease was made and he was treated with rituximab that resulted in complete remission.