A case of retroperitoneal and mediastinal fibrosis exhibiting elevated levels of IgG4 in the absence of sclerosing pancreatitis (autoimmune pancreatitis)

There is now increasing evidence that IgG4 is closely involved in idiopathic sclerosing lesions, such as sclerosing pancreatitis and sclerosing sialadenitis. In this report, we describe a case of IgG4-related retroperitoneal and mediastinal fibroses. A 52-year-old man presented with dull back pain and was found to have a continuously surrounding paraaortic mass. A biopsy specimen taken from the retroperitoneum showed a diffuse lymphoplasmacytic...