Contrast-enhanced endoscopic ultrasound in the diagnosis of autoimmune pancreatitis

Autoimmune pancreatitis is a rare condition which can mimic pancreatic carcinoma. We report the cases of 10 patients with autoimmune pancreatitis investigated in two different centers using contrast-enhanced endosonography. In these patients, contrast-enhanced endosonography showed a unique vascularization pattern which makes it easy to discriminate between autoimmune pancreatitis and lesions caused by pancreatic cancer. Lesions caused by autoimmune pancreatitis and the surrounding pancreas typically showed hypervascularization, whereas lesions caused by pancreatic cancer were hypovascularized. This was true for all patients with the exception of one who showed a normal vascularization pattern in comparison with normal patients and no signs of hypovascularization. Final diagnosis was achieved either by transcutaneous biopsy or a combination of endoscopic fine-needle aspiration with IgG4 immunostaining of the sample. All patients were followed up over a period of at least 12 months to rule out pancreatic carcinoma.