The subject was a 45-year-old male who was examined for acute pancreatitis. Endoscopic ultrasound (EUS) revealed a low echoic tumor with a poorly defined border and a poorly vascularized interior at the pancreatic tail. Contrast-enhanced EUS showed that the tumor was hypovascular, and its interior exhibited non-uniform contrast staining. A clinical diagnosis of pancreatic ductal carcinoma (PDAC) was made. Distal pancreatectomy was performed, but pancreatic neuroendocrine neoplasm (PNEN), NET G2, with a total of six tumors up to 3 mm in size, was pathologically diagnosed. The aggregation of PNEN that were a few millimeters in size in a small area with fibrosis around tumors occured tumor-associated pancreatitis and appeared similar to PDAC during imaging, which probably caused the difficulties in the preoperative diagnosis.
