Fig. 1.

a Endoscopic image depicting a 3-cm mass in the descending portion of the duodenum that is adjacent to the oral side but does not involve the papilla of Vater. The papilla of Vater is indicated by an arrow. b Endoscopic ultrasonography image showing the tumor partially invading the head of the pancreas (arrow). c Duodenography showing a protruding lesion in the descending portion of the duodenum (arrow). d Computed tomography image showing an ill-defined hypervascular mass (arrow). The tail of the pancreas had been minimally resected during a previous surgery. e Magnifying endoscopy depicting a diminished surface pattern of the gastrointestinal epithelium across the entire surface of the tumor. f Magnifying endoscopy combined with NBI depicting a diminished capillary network pattern.