Diagnosis of an intraductal papillary neoplasm of the bile duct with fibrovascular stalks using detective flow imaging.

Intraductal papillary neoplasm of the bile duct (IPNB) is a type of epithelial tumor characterized by papillary proliferation within the bile duct. It is defined histologically as a papillary or villous neoplasm covering the delicate fibrovascular stalks within the bile ducts [1] [2]; however, imaging of the fibrovascular stalks has not previously been reported in IPNB. Recent studies have reported on the usefulness of detective flow imaging (DFI) during endoscopic ultrasound (EUS) for the detailed evaluation of vessels in pancreaticobiliary disease, without the use of contrast agents [3] [4] [5]. Herein, we describe the usefulness of DFI in identifying the fibrovascular stalks in IPNB.