Ansa Pancreatica: A Rare Culprit in Recurrent Acute Pancreatitis

Abstract

Ansa pancreatica is a rare anatomical variation of the pancreatic duct system, characterized by a reversed S-shaped loop that connects the main pancreatic duct to the minor papilla. Its clinical significance, particularly with recurrent acute pancreatitis, has been a subject of interest, but remains poorly understood due to the rarity of reported cases. We report the case of a 34-year-old female with a history of multiple episodes of acute pancreatitis, diagnosed with ansa pancreatica using magnetic resonance cholangiopancreatography (MRCP). The patient presented with severe epigastric pain radiating to the back, accompanied by vomiting and nausea. Laboratory findings revealed elevated serum amylase and lipase levels. MRCP imaging identified the ansa pancreatica, showing a distinct looping ductal variant terminating near the minor papilla. The patient underwent successful endoscopic treatment with significant improvement in symptoms and no recurrence of pancreatitis at follow-up. In this case, the presence of ansa pancreatica underscores the variant's potential role in predisposing individuals to recurrent episodes of acute pancreatitis. The literature review highlights the anatomical description of ansa pancreatica and its speculated pathophysiological mechanism leading to pancreatitis, primarily due to impaired pancreatic juice drainage. Despite its rarity, recognizing ansa pancreatica is crucial for the appropriate management of idiopathic recurrent pancreatitis, especially in cases where conventional causes are absent. This case report and literature review emphasize the importance of considering ansa pancreatica in the differential diagnosis of recurrent acute pancreatitis. Further research is needed to elucidate the exact mechanism by which this anatomical variant contributes to pancreatitis and to explore potential therapeutic interventions. Awareness and early detection of ansa pancreatica can lead to targeted treatments, reducing the morbidity associated with recurrent pancreatitis episodes.

Keywords: ansa pancreatica; clinical diagnosis; extrahepatic biliary tract; pancreatic ductal anomalies; recurrent acute pancreatitis.

Figure 1. MRCP depicting pancreatic and biliary ductal system

The blue arrow indicates CBD; the white arrow shows MPD; the yellow arrow depicts an S-shaped loop connecting the major and minor pancreatic duct. CBD - common bile duct; MPD - major pancreatic duct; MRCP - magnetic resonance cholangiopancreatography

Figure 2. The illustrations depict the MPD formed by the anastomosis of the duct of distal two-thirds of the DPB and the duct of the entire VPB

A: During the eighth week of embryogenesis, the ventral and the dorsal pancreatic ducts arise from the Foregut. B: Migration of ventral pancreatic bud towards dorsal pancreatic bud; C: Fusion of dorsal pancreatic bud with ventral pancreatic bud resulting in the formation of the main pancreatic duct (duct of Wirsung), which connects to the second part of the duodenum. The accessory duct is formed from the ventral pancreatic duct and provides an alternate route for pancreatic secretions to enter the duodenum. MPD - main pancreatic duct; S - stomach; GB - gall bladder; D - duodenum; CHD - common hepatic duct; BD - bile duct; VPD - ventral pancreatic bud; DPB - dorsal pancreatic bud; APD - accessory pancreatic duct Image credit: Varna Taranikanti

Figure 3. The illustrations depict the ansa pancreatica formed from the proximal part of APD that loops in a S-shaped manner

A: Normal embryogenesis of VPD and MPD. B: Looping/kinking of MPD. C: S-shaped loop (ansa pancreatica) connecting MPD with APD; failure of normal fusion between the ventral and dorsal pancreatic ducts leads to the formation of an S-shaped loop where there is kinking of the main pancreatic duct and connection of MPD with APD through the loop. APD - accessory pancreatic duct; MPD - main pancreatic duct; VDP - ventral pancreatic bud Image credit: Varna Taranikanti