A case of annular pancreas complicated with pancreatic ductal adenocarcinoma diagnosed with linear endoscopic ultrasound

A case of annular pancreas complicated with pancreatic ductal adenocarcinoma diagnosed with linear endoscopic ultrasound Annular pancreas (AP) is an uncommon congenital anomaly characterized by pancreatic tissue partially or completely encircling the duodenum [1].AP complicated with pancreatic ductal adenocarcinoma (PDAC) is extremely rare to be reported [2,3].The diagnosis of AP can be confirmed by endoscopic ultrasound (EUS) [4,5].Here, we present a patient diagnosed with AP accompanied by PDAC through linear EUS and EUS-guided fine-needle biopsy (EUS-FNB).The patient was a 78-year-old woman suffering from abdominal distension and anorexia, which had lasted for 2 months.In the last 1 week, the above-mentioned malaise was intensified, and abdominal pain occurred occasionally.Thus, she was admitted to our hospital in order to seek clinical evaluation and treatment in March 2023.On admission, physical examination revealed no anemia and yellowish discoloration of skin and sclera.Carbohydrate antigen 19-9 (CA19-9) was elevated to 477.5 U/ml ( 43 U/ml).Contrastenhanced computed tomography (CT) suggested a ring of pancreas surrounding the duodenum and a space-occupying lesion in the pancreatic head ( Fig. 1).Contrast-enhanced magnetic resonance imaging (MRI) indicated the existence of AP, but it was not sure whether it was combined with focal pancreatitis or pancreatic cancer ( Fig. 2).Linear EUS showed that the pancreas extended to the outer side of the duodenum ( Fig. 3 a).Meanwhile, the pancreatic duct was observed coursing around the duodenum ( Video 1).AP was confirmed.Furthermore, linear EUS showed a hypoechoic mass in the intersection of AP and pancreatic head, measuring 24 21 mm, which resulted in significant dilation of the accessory pancreatic duct ( Fig. 3 b).Noteworthily, the descending part of the duodenum had a narrowed lumen and the endoscopy could not pass through ( Fig. 4).Using a 22-gauge nee-E-Videos Fig. 1 Contrast-enhanced abdominal CT scan.a A ring of pancreas was seen around the second part of the duodenum (white arrow).b A hypodense mass was indicated (red arrow).Abbreviation: CT