## 4 Case Presentation
Another EUS was performed, showing persistent inflammation and hyperechoic foci with shadowing of the upper duodenal knee, along with peri-duodenal effusions; the appearance of the pancreatic parenchyma had improved, but the hypoechoic texture and inflammatory oedema persisted in the cephalic portion, with several images on EUS suggesting pancreas divisum. Bile sludge was detected in the common bile duct. Endoscopic retrograde cholangio-pancretoagraphy (ERCP) was therefore indicated for drainage of the bile sludge and stent placement. [PERSON]'s papilla sphincetotomy was performed, leading  
Figure 3: MRCP showing necrotic areas of the head of the pancreas and multiple peri-duodenal fluid collections. to spontaneous contrast medium drainage and minimal sludge. [PERSON]'s opacification did not opacify the main pancreatic duct, and only its secondary branches were visible. In addition, the guidewire through [PERSON]'s duct did not proceed into the main pancreatic duct, as occurs in complete pancreas divisum. A 5 Fr, 5 cm monophasic tail stent was inserted in this region to drain the head of the pancreas. Subsequently, the minor papilla was cannulated with an ultra-thin catheter through the Santorini duct, and a guidewire was advanced up to the tail of the pancreas. A sphincterotomy of the minor papilla was performed using a 4 French papillotome. The opacification showed an intact main pancreatic duct, communicating with the Santorini duct, confirming the diagnosis of complete pancreas divisum. A 5 French, 12 cm stent was placed through the Santorini duct into the main pancreatic duct for drainage (Figure 5). A few days after the endoscopic procedure, the patient developed increased abdominal pain, fever (up to 38 \({}^{\circ}\)C), anaemia requiring blood transfusions, and increases in inflammation markers. A CECT scan revealed the formation of abscesses in the known pancreatic collections, as well as an increase in the size of the perirenal effusion. Antibiotics were started and the interventional radiologist used percutaneous drainage to remove the  
Figure 4: MRCP showing a case of complete pancreas divisum (type 1): absence of communication between the main pancreatic duct and [PERSON]’s duct (head of arrow); dominant dorsal duct drainage in the minor papilla (grey arrow). The biliary tract crosses the main pancreatic duct. Figure 5: The two pancreatic stents through minor and major papillae are shown. collected fluid. This led to a progressive improvement in the patient's clinical condition as confirmed by a subsequent CT scan. The abdominal drainage was then removed, and the patient was discharged. Over the next two years, the patient underwent four replacements of the pancreatic stent without any complications. In August 2021, the patient was re-hospitalized after developing acute pancreatitis with enlargement of the known pancreatic collection (64 \(\times\) 52 mm vs. 20 mm), which showed an infected and granular appearance on CECT. WBC were 14,500 cells/\(\mu\)L and CRP was 32 mg/dL (normal values \(<\) 0.7 mg/dL). He subsequently underwent EUS, which identified a large heterogeneous retro-gastric collection of at least 6 cm. EUS-guided access was performed using a 15 \(\times\) 10 mm metal stent (Hot Axios), obtaining purulent material outflow (Figure 6). The subsequent ERCP demonstrated the minor papilla with a pancreatic stent in place; the Vater's papilla appeared normal. The pancreatic stent was removed. Pancretography did not show contrast medium leaks; the Santorini duct appeared regular in calibre and course. A 7 Fr, 5 cm stent was then repositioned through the minor papilla, with effective drainage of pancreatic juice into the duodenum. An 8.5 French catheter was placed in the collection to drain it at the end of the procedure. Smooth haemostasis was achieved. Inflammatory markers improved along with the clinical condition. Before discharge, an ERCP confirmed the presence of a metal stent in the posterior gastric wall.