Abstract
A 42-year-old man complaining of jaundice was referred to our hospital with a suspected diagnosis of pancreatic cancer following examinations at another hospital. Imaging methods revealed a tumor about 4cm in diameter at the pancreas head with suspected invasion into the portal vein. PET-CT showed uptake of fluorine-18 fluorodeoxyglucose (18F-FDG) with the SUV value of 4.7 at the same area as the pancreas head tumor. Accordingly the patient was operated on with the preoperative diagnosis of pancreatic cancer. The histopathological examinations demonstrated no tumor cells at the area where the tumor was present but showed infiltration of inflammatory cells. In addition immunostaining showed IgG4 positive inflammatory cells. IgG4-relating autoimmune pancreatitis was thus diagnosed.
Autoimmune pancreatitis is a pancreatitis in which the participation of autoimmunity is suspected in the onset and it shows uptake of 18F-FDG on PET-CT, so that the differentiation between the disease and pancreatic cancer is important. In the case of a tumor localized in the pancreas, careful attitude would be mandatory to make diagnosis, entertaining the possibility of this disease. This paper deals with a recent case of autoimmune pancreatits in which we had difficulties in making differential diagnosis from pancreatic malignancy due to 18F-FDG uptake on PET-CT, together with some bibliographical comments.
