What's your diagnosis? It's not an abcess. The patient recently suffered from abdominal pain and nausea. I'll post the correct answer in a few days!
Correct answer: Pancreatic pseudocyst. It's most commonly a result of pancreatitis and forms 4-6 weeks after start of the symptoms. Unlike true cysts, pseudocysts are lined with granulation tissue. There's a collection of fluid containing pancreatic enzymes, hemolysed blood and necrotic debris around the pancreas; when this becomes infected, it's an abcess.