Microscopic findings in EUS-guided fine needle (SharkCore) biopsies with type 1 and type 2 autoimmune pancreatitis

The International Consensus Diagnostic Criteria (ICDC) for the diagnosis of autoimmune pancreatitis (AIP) include the histological criterion that is based on either pancreatic core needle biopsies (CNBs) or surgical specimens. However, CNBs are difficult to obtain by endoscopic ultrasound (EUS). EUS fine-needle aspiration (EUS-FNA) cytology is usually not sufficient for the diagnosis of AIP, but may sometimes contain tissue microfragments. Another approach is EUS-guided histological fine-needle biopsy (EUS-FNB), using needles such as the SharkCore or ProCore needle. Published data regarding EUS-guided SharkCore FNB for the diagnosis of AIP are lacking. We aimed to describe our histological findings in one type 1 and two type 2 AIP patients who underwent EUS SharkCore FNB. The EUS-FNBs of two patients fulfilled the histological level 2 ICDC for type 1 AIP or type 2 AIP. The EUS-FNB of one patient fulfilled the histological level 1 ICDC for type 2 AIP. The tissue cylinders and fragments measured 55, 28 and 17 mm in total. At least histological level 2 ICDC were fulfilled in all cases, and our findings regarding the utility of EUS SharkCore FNB for the diagnosis of AIP are therefore promising, but further studies based on larger numbers of patients are warranted.