Differential Diagnosis

The patient's presentation of epigastric pain, tenderness, a palpable mass in the epigastrium, and ultrasound findings of a mass with a thick wall and fluid, combined with a history of pancreatitis 6 weeks ago and elevated WBC, suggests several possible diagnoses. These can be categorized as follows:

• Single Most Likely Diagnosis
  • A. Pancreatic Pseudocyst: This is a fluid collection that can develop in the abdomen after an episode of pancreatitis. The presence of a mass with fluid on ultrasound, especially with a thick wall, is consistent with a pseudocyst. The timing, 6 weeks after pancreatitis, also fits, as pseudocysts typically develop weeks after the initial inflammatory process.
• Other Likely Diagnoses
  • B. Pancreatic Abscess: An abscess is a collection of pus that can form in or around the pancreas, often as a complication of pancreatitis. The elevated WBC count and the presence of a mass with fluid on ultrasound could suggest an abscess, especially if the fluid is infected.
  • C. Walled Off Necrosis: This condition involves a collection of dead pancreatic tissue that becomes encapsulated by a wall of fibrous tissue. It can present similarly to a pseudocyst but typically contains necrotic debris rather than just fluid. The ultrasound findings and clinical presentation could be consistent with walled-off necrosis, especially if there's a history of necrotizing pancreatitis.
• Do Not Miss Diagnoses
  • D. Pancreatic CA (Cancer): Although less likely given the recent history of pancreatitis, pancreatic cancer can present with a mass in the pancreas and should not be missed due to its significant implications for treatment and prognosis. A thorough evaluation, including possibly a CT scan or biopsy, might be necessary to rule out cancer, especially if there are other risk factors or if the patient does not improve with treatment for the other conditions.
• Rare Diagnoses
  • Other rare conditions such as pancreatic lymphoma or metastasis to the pancreas from another primary cancer could also present with a mass but are less likely given the clinical context of recent pancreatitis. These would be considered if initial treatments fail or if there are atypical features on imaging or in the clinical presentation.