eMedicine Specialties > Gastroenterology > Pancreas

Pancreatic Pseudocysts: Differential Diagnoses & Workup

Author: Louis R Lambiase, MD, Associate Professor of Medicine, University of Florida College of Medicine; Chief, Division of Gastroenterology, Department of Internal Medicine, University of Florida Health Science Center/Jacksonville
Contributor Information and Disclosures

Updated: Mar 18, 2008

Differential Diagnoses

Pancreatic Cancer
Pancreatic Necrosis and Pancreatic Abscess
Pancreatic Pseudoaneurysm
Pancreatitis, Acute
Pancreatitis, Chronic
von Hippel-Lindau Disease

Other Problems to Be Considered

Organized pancreatic necrosis
Acute pancreatic fluid collections
Serous cystadenoma of the pancreas
Mucinous cystadenoma of the pancreas
Mucinous cystadenocarcinoma
Pancreatic retention cyst

Workup

Laboratory Studies

  • Serum tests have limited use.  
    • Amylase and lipase levels are often elevated but may be within reference ranges.
    • Bilirubin and liver function test (LFT) findings may be elevated if the biliary tree is involved.
  • Analysis of the cyst fluid may help differentiate pseudocysts from tumors. Attempt to exclude tumors in any patient who does not have a clear history of pancreatitis.  
    • Carcinoembryonic antigen (CEA) and carcinoembryonic antigen-125 (CEA-125) tumor marker levels are low in pseudocysts and elevated in tumors.
    • Fluid viscosity is low in pseudocysts and elevated in tumors.
    • Amylase levels are usually high in pseudocysts and low in tumors.
    • Cytology is occasionally helpful in diagnosing tumors, but a negative result does not exclude tumors.
    • A CEA level of greater than 400 ng/mL within the cyst fluid strongly suggests malignancy.

Imaging Studies

  • Abdominal ultrasound: While cystic fluid collections in and around the pancreas may be visualized via ultrasound, the technique is limited by the operator’s skill, the patient's habitus, and any overlying bowel gas. As such, ultrasound is not the study of choice to establish a diagnosis.
  • Abdominal CT scan  
    • CT scan is the imaging criterion standard for pancreatic pseudocysts. It has a sensitivity of 90-100% and is not operator dependent.
    • The usual finding on CT scan is a large cyst cavity in and around the pancreas.
    • Multiple cysts may be present.
    • The pancreas may appear irregular or have calcifications.
    • Pseudoaneurysms of the splenic artery, bleeding into a pseudocyst, biliary and enteric obstruction, and other complications may be noted on CT scan.
    • The CT scan provides a very good appreciation of the wall thickness of the pseudocyst, which is useful in planning therapy.
  • Endoscopic retrograde cholangiopancreatography  
    • Endoscopic retrograde cholangiopancreatography (ERCP) is not necessary in diagnosing pseudocysts; however, it is useful in planning drainage strategy.
    • A study by Neil et al investigated the use of ERCP and the treatment of pseudocysts and acute pancreatitis and reported that a change in management occurred 35% of the time after the ERCP findings in pseudocysts were evaluated. Therefore, many authors recommend performing an ERCP before contemplated drainage procedures.
  • MRI  
    • MRI is not necessary to establish a diagnosis of pseudocysts; however, it is useful in detecting a solid component to the cyst and in differentiating between organized necrosis and a pseudocyst.
    • A solid component makes catheter drainage difficult; therefore, in the setting of acute necrotizing pancreatitis with resultant pseudocyst, an MRI may be very important before a planned catheter drainage procedure.
  • Endoscopic ultrasound  
    • Endoscopic ultrasound (EUS) is not necessary to establish a diagnosis but is very important in planning therapy, particularly if endoscopic drainage is contemplated.
    • A gastric wall with a thickness greater than 1 cm next to the cyst tends to predict a poor outcome with endoscopic drainage.
    • EUS may also be helpful in detecting small portal collaterals from otherwise undetected portal hypertension that may increase bleeding risks with transmural drainage.
    • Transmural drainage may be performed only when the symptomatic pseudocyst is positioned next to the gut wall.

Histologic Findings

Histologic findings vary with age because older cysts have thicker walls with more collagen. The etiology of the cyst does not change the histology.

  • Zone 1 - Hemosiderin pigment and loose connective tissue
  • Zone 2 - Inflammatory cells and capillary-rich fibrous tissue
  • Zone 3 - Hyalinized acellular connective tissue
  • Zone 4 - Capillary-rich fibrous stroma

More on Pancreatic Pseudocysts

Overview: Pancreatic Pseudocysts
Differential Diagnoses & Workup: Pancreatic Pseudocysts
Treatment & Medication: Pancreatic Pseudocysts
Follow-up: Pancreatic Pseudocysts
Multimedia: Pancreatic Pseudocysts
References
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References

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  2. Aljarabah M, Ammori BJ. Laparoscopic and endoscopic approaches for drainage of pancreatic pseudocysts: a systematic review of published series. Surg Endosc. Nov 2007;21(11):1936-44. [Medline].

  3. Beckingham IJ, Krige JE, Bornman PC, Terblanche J. Long term outcome of endoscopic drainage of pancreatic pseudocysts. Am J Gastroenterol. Jan 1999;94(1):71-4. [Medline].

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Further Reading

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Keywords

pancreatic fluid collections, organized necrosis of the pancreas, pancreatic cysts, pancreatitis, abdominal trauma, pancreatic ducts, persistent abdominal pain, anorexia, abdominal mass, jaundice, sepsis, pleural effusion, scleral icterus, percutaneous catheter drainage

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Contributor Information and Disclosures

Author

Louis R Lambiase, MD, Associate Professor of Medicine, University of Florida College of Medicine; Chief, Division of Gastroenterology, Department of Internal Medicine, University of Florida Health Science Center/Jacksonville
Louis R Lambiase, MD is a member of the following medical societies: American Gastroenterological Association, American Pancreatic Association, and American Society for Gastrointestinal Endoscopy
Disclosure: Nothing to disclose.

Medical Editor

David Greenwald, MD, Fellowship Program Director, Associate Professor, Department of Medicine, Division of Gastroenterology, Montefiore Medical Center, Albert Einstein College of Medicine
David Greenwald, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, and American Society for Gastrointestinal Endoscopy
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Simmy Bank, MD, Chair, Professor, Department of Internal Medicine, Division of Gastroenterology, Long Island Jewish Hospital, Albert Einstein College of Medicine
Disclosure: Nothing to disclose.

CME Editor

Alex J Mechaber, MD, FACP, Assistant Dean for Medical Curriculum, Associate Professor of Medicine, Division of General Internal Medicine, University of Miami Miller School of Medicine
Alex J Mechaber, MD, FACP is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians-American Society of Internal Medicine, and Society of General Internal Medicine
Disclosure: Nothing to disclose.

Chief Editor

Julian Katz, MD, Clinical Professor of Medicine, Drexel University College of Medicine; Consulting Staff, Department of Medicine, Section of Gastroenterology and Hepatology, Hospital of the Medical College of Pennsylvania
Julian Katz, MD is a member of the following medical societies: American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Geriatrics Society, American Medical Association, American Society for Gastrointestinal Endoscopy, American Society of Law Medicine and Ethics, American Trauma Society, Association of American Medical Colleges, and Physicians for Social Responsibility
Disclosure: Nothing to disclose.

 
 
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