Periduodenal panniculitis due to spontaneous rupture of a pancreatic pseudocyst into the duodenum.

We report a patient with transient periduodenal panniculitis due to spontaneous rupture of a pancreatic pseudocyst into the duodenum. He developed sudden onset of severe epigastric and back pain with jaundice, mimicking the symptoms of acute pancreatitis. However, the serum and urinary amylase levels did not increase. CT scans showed disappearance of his pseudocyst and periduodenal panniculitis without any evidence of acute pancreatitis. The CT findings of periduodenal panniculitis and his symptoms both improved within 3 weeks. A duodenal fistula leading to the remnant pseudocyst and narrowing of the periduodenal portion of the common bile duct were demonstrated by endoscopic retrograde cholangiopancreatography.