Differential Diagnosis

• Single most likely diagnosis
  • B. Pancreatic Abscess (infected WON): This is the most likely diagnosis given the patient's history of pancreatitis, current symptoms of epigastric pain and tenderness, the presence of a mass with a thick wall and fluid on ultrasound, and elevated WBC count. These findings are consistent with an infected walled-off necrosis (WON), which is a complication of pancreatitis.
• Other Likely diagnoses
  • A. Pancreatic pseudocyst: While possible, the presence of a thick-walled mass with fluid and elevated WBC count makes this less likely than a pancreatic abscess. Pseudocysts are typically not infected and may not present with such a significant inflammatory response.
  • C. Walled off necrosis: This could be considered if the collection was not infected. However, the high WBC count suggests an infectious component, making pancreatic abscess more likely.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • D. Pancreatic CA: Although less likely given the acute presentation and history of pancreatitis, pancreatic cancer can sometimes present with a mass and should be considered to avoid missing a potentially fatal diagnosis.
• Rare diagnoses
  • Other rare conditions such as a pancreatic duplication cyst or a cystic neoplasm could be considered but are less likely given the clinical context and would typically require further diagnostic evaluation to distinguish from the more common complications of pancreatitis.