A Case of IgG4-Related Disease: A Unique Presentation of a Rare Entity

Abstract

IgG4-related disease is a rare, systemic fibroinflammatory condition characterized by lymphoplasmacytic infiltrates and often times elevated serum IgG4 levels. Multiple organs are implicated in the disease and although the pathogenesis is not entirely understood, genetic risk factors and autoimmune dysregulation have been associated. Pathology from biopsied lesions is varied and can range from a dense lymphoplasmacytic infiltrate to fibrosis. Currently, there are limited reports of IgG4-related disease in the literature. A 69 year-old female with a past medical history significant for salivary gland tumor (s/p resection and radiation), rheumatoid arthritis (on Methotrexate), alcohol use (2-3 glasses of wine for several years) presented to hepatology clinic for evaluation of elevated liver function tests noted on routine blood work. ALP was 367 IU/L, ALT 162 IU/L and AST 67 IU/L. CA 19-9 was also elevated to 45 U/mL, however MRI and EUS were unremarkable. Liver biopsy showed portal fibrosis, lymphocytic, neutrophilic and eosinophilic portal and lobular hepatitis with bile ductular proliferation. After an unrevealing extensive workup for other causes of abnormal liver tests, it was thought the abnormal tests and biopsy finding may be secondary to ethanol abuse and methotrexate. Over the subsequent year, the patient continued to have elevated liver function tests, a thirty-five pound weight loss, jaundice and pruritus. MRI of the abdomen revealed an infiltrating peri-choledochal, peripancreatic, porta hepatic and retroperitoneal soft tissue mass, narrowing the common bile duct and multiple enlarged retroperitoneal and pericardial lymph nodes. EUS showed an irregular, 2.3 x 2.3 cm, poorly defined area within the region of the head of the pancreas, dilation of the pancreatic duct and distal common bile duct stricture. Biopsies were not performed, and cytology from FNA revealed only benign pancreatic acini. IgG4 levels were ordered to evaluate for IgG4 related autoimmune pancreatitis/sclerosing cholangitis and were elevated to 125 mg/dL. Given the elevated IgG4, and multiple organ dysfunction, a presumed diagnosis of IgG4-related disease was made. Although glucocorticosteroids are the mainstay of therapy, the patient has not since returned to clinic. IgG4-related disease is a rare yet potentially treatable entity that can mimic primary organ disease or malignancy, yet should always remain in the differential diagnosis. Close follow up and cognizance of this disease entity is critical as a lag in treatment can have significant implications.