Autoimmune pancreatitis (AIP) can closely resemble pancreatic cancer, but these two diseases require distinctly different courses of treatment. A new study suggests that an endoscopic procedure using a larger-gauge needle may offer a solution for making this important differential diagnosis. The study, "Diagnosis of autoimmune pancreatitis by EUS-guided FNA using a 22-gauge needle: a prospective multicenter study," is published in the November issue of GIE: Gastrointestinal Endoscopy, the monthly, peer-reviewed journal of the American Society for Gastrointestinal Endoscopy (ASGE).
AIP, a chronic inflammation of the pancreas that can be treated with steroids, is a relatively newly recognized disease. Examination of tissue specimens from the pancreas is necessary for diagnosis and subsequent treatment. But previously specimens obtained using endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) have proven inadequate because of the small sample size that can be procured via this method. The researchers evaluated whether this procedure would have increased efficacy using a 22-gauge needle rather than the traditional smaller size.
Based on imaging characteristics suggesting AIP, 78 patients were selected for the innovative EUS-FNA procedure over a 13-month period. Tissue samples were evaluated for sampling conditions, certain elevated plasma cell counts indicating AIP, storiform fibrosis (a pattern of scarring) and obliterative phlebitis (vein inflammation).
Tissue specimens were obtained from 62 patients, and features indicative of AIP were identified in 45 of these. Therefore, 45 of 78 patients (58 percent) could be diagnosed with AIP according to International Consensus Diagnostic Criteria.
The authors concluded that EUS-FNA with a 22-gauge needle may be useful for the diagnosis of AIP through microscopic examination of tissue samples.