Case Presentation: A 73 year old man with a past medical history notable for type 2 diabetes and hypothyroidism presented with ten days of dark urine and jaundice. He had developed worsening jaundice, pruritus, and a five pound weight loss prior to presentation. Labs showed alkaline phosphatase 731, ALT 369, AST 174, total bilirubin 5.64 mg/dL, and CA 19-9 of 1143. CT abdomen and pelvis on admission showed a 2.4 cm right renal mass, peripancreatic lymphadenopathy measuring 2.6 cm with biliary obstruction, and a presacral soft tissue mass measuring 7.6 cm, concerning for either lymphoma or metastatic pancreatic cancer. He then underwent EGD/EUS/ERCP which noted a mass-like thickening of the intrapancreatic portion of the bile duct. A biliary stent was placed and the mass was sampled with fine needle aspiration cytology (FNAC). The stenting resulted in downtrending bilirubin, improved jaundice and pruritus, but the FNAC results were non-diagnostic for malignancy. Due to high clinical suspicion for cholangiocarcinoma or lymphoma with bile duct involvement, the patient underwent repeat EGD/EUS/ERCP as well as IgG4 testing. The biopsies were once again negative, but the patient’s IgG4 levels were elevated to 492, suggesting IgG4- related disease. The patient began treatment in the outpatient setting with steroids, immune suppression, and interventional procedures to relieve obstruction.
Discussion: IgG4-related disease is a complex immune mediated disorder which is poorly understood. While the condition involves the development of IgG4 antibodies, these are not currently considered to be pathologic, and moreso a secondary result of an underlying inflammatory process. The disease can affect multiple organ systems with inflammatory masses that can mimic malignancy upon initial presentation as in our patient. It is important to broaden the differential when initial malignant work-up returns negative, and to consider IgG4-related disease. There are several common presentation phenotypes which include autoimmune pancreatitis, sclerosing cholangitis, salivary gland involvement, orbital disease, and retroperitoneal fibrosis. Treatment is often multi-modal, involving an initial therapy with steroids and immunosuppression as well as maintenance therapy with interventions as necessary to relieve obstructions for often recurrent disease.
Conclusions: 1. Consider IgG4-related disease in the setting of multiple organ masses with negative malignancy workup.2. Recognise that the treatment of IgG4-related disease is multi-modal with long term systemic steroids and immune suppression.
