Clinical aspects of autoimmune pancreatitis in Sjogren's syndrome.

Over the past two decades, the quality of diagnostic imaging in the pancreas has been improved by technical and instrumental progress made in ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). The examination using ultrasound is inexpensive, non-invasive, and can be rapidly performed. It is often the test of choice in the evaluation of suspected pancreatic lesions. However, both the diagnosis of chronic pancreatitis at an early stage and the differential diagnosis between chronic pancreatitis and small pancreatic cancers are still difficult to make. Ultrasonography of the abdomen has become a routine imaging test when patients have abdominal pain that may be of pancreatobiliary origin or when they have a periodical checkup. Therefore, an incidental finding of diffuse or focal swelling of the pancreas is one of the frequent diagnostic clues used to detect autoimmune pancreatitis and small pancreatic cancers. Such a focal pancreatic mass is often mistaken for a small localized pancreatic cancer even after extensive efforts are made to differentiate chronic pancreatitis from pancreatic cancer by using elaborate imaging modalities including fine needle aspiration biopsy (FNAB). Knowledge of autoimmune pancreatitis or chronic pancreatitis with irregular narrowing of the main pancreatic duct has become important for clinicians, because most patients respond to oral steroid therapy and it saves patients from unnecessary laparotomy and pancreas resection. Over half the cases of autoimmune pancreatitis that have been reported are from Japan. We would like to discuss the clinical features and the course of autoimmune pancreatitis associated with autoimmune diseases in Japan, especially Sjogren’s syndrome (SjS), and also review the diagnostic and therapeutic aspects of the disease.