Spontaneous pancreatic pseudocyst – superior mesenteric vein fistula: A rare complication of chronic pancreatitis

Abstract

Pseudocyst formation is common in chronic pancreatitis. A rare subset of these patients may develop fistulization between the pseudocyst and the portal vein system. We report a case of spontaneous pancreatic pseudocyst – superior mesenteric vein fistula in a 61-year-old male with a history of chronic recurrent calcifying pancreatitis. The fistulous connection was correctly identified on both computed tomography and magnetic resonance cholangiopancreatography (MRCP), and the patient was treated successfully with a conservative approach. Our case report aims to educate on this rare and potentially fatal vascular complication of chronic pancreatitis and to discuss the role of modern noninvasive imaging techniques, such as T2-weighted MRI/MRCP, in establishing this diagnosis and making a decision regarding its management.

Pancreaticoportal Vein Fistula After Severe Acute Pancreatitis

“…There are 2 probable theories proposed 1 . Some researchers propose that the pathogenesis is related to portal vein thrombosis induced by mass effect and vessel compression by an unruptured pseudocyst, whereas others believe that amassed pancreatic enzymes in a pseudocyst can erode the wall of the portal vein 1,6 . In this case, the patient had no evidence of portal vein thrombosis or pseudocysts during the course of disease.…”

Spontaneous Pancreatic Pseudocyst-Superior Mesenteric Vein Fistula

“…We favor avoidance of therapeutic anticoagulation for associated thrombi because of bleeding risk, and we advocate for early enteral nutrition in individuals not tolerating oral intake. 1,5 Infectious complications have been described in numerous PP-PV cases, and we suggest the use of prophylactic antibiotics as part of initial management.…”

“…3 This complication has been described more frequently in men and those with significant alcohol use. 1,[4][5][6] Most cases develop in the context of chronic pancreatitis and less commonly during episodes of acute pancreatitis. 4,7 The exact mechanism remains disputed.…”

“…One possible explanation is that the thrombus develops first because of stasis from compression of the vein by the pseudocyst and the thrombus then acts as a nidus for the fistula to develop. 1,[3][4][5][6] It is also possible that the fistula develops first because of pancreatic enzymes destroying the pseudocyst and vein walls and inflammation from the pancreatic enzymes within the vein leads to thrombosis. 1,3,[5][6][7][8] Several cases that involved serial imaging documented the presence of fistula before thrombosis, suggesting that at least in some cases, the second theory seems more likely.…”

“…1,[3][4][5][6] It is also possible that the fistula develops first because of pancreatic enzymes destroying the pseudocyst and vein walls and inflammation from the pancreatic enzymes within the vein leads to thrombosis. 1,3,[5][6][7][8] Several cases that involved serial imaging documented the presence of fistula before thrombosis, suggesting that at least in some cases, the second theory seems more likely. 4,8 CT is a common initial imaging modality for patients with PP-PV fistulas.…”