The Aberrant Passage: A Rare Spontaneous Pancreatic Pseudocyst-Portal Vein Fistula.

A 45-year-old man with a history of alcohol-induced chronic pancreatitis presented with acute abdominal pain and low-grade fever. Initial imaging with contrast-enhanced CT showed a widened portal vein containing fluid that appeared different from a typical solid clot. Further specialised magnetic resonance imaging (MRCP) confirmed a fistula connecting the pancreatic duct directly to the portal vein. On that MRCP imaging, there's evidence of intravascular fluid collection within the portal vein showing homogeneous T2-hyperintense signal characteristics with the adjacent pancreatic fluid, suggesting direct extension. An axial T2-weighted MRI confirmed the existence of the fistula. A review of a previous MRCP performed six months prior showed a pancreatic head pseudocyst already extending into the portal vein, suggesting that the fistula developed gradually over several months. The diagnosis was confirmed by sampling the fluid within the vein, which showed significant levels of pancreatic enzymes.