Pancreatic Fluid Collections

Pancreatic fluid collections result from many causes, including damage to the pancreas or premalignant or malignant conditions.  Fluid collections can be large and cause symptoms such as pain and fevers, although most are smaller and asymptomatic.

Classification of Pancreatic Fluid Collections

There are many types of pancreatic fluid collections.  The most common is called a pancreatic pseudocyst.  These collections are called “pseudocysts” because they lack what is called an epithelial layer, which is typically present in “true” cysts.  However, pseudocysts always develop as a result of injury to the pancreas and are defined by the fact that that are fluid filled.  Most pseudocysts are asymptomatic and will resolve on their own.  However, occasionally, these need to be drained if pain, fever or infection develop. Another type of fluid collection that results from pancreatic injury is called Walled Off Pancreatic Necrosis or “WOPN.”  In the past, WOPN has been called other terms such as pancreatic abscess.  These collections are similar to pseudocysts in that they result from injury to the pancreas.  However, in contrast, these are filled with solid debris, and usually do not resolve on their own without operative intervention. There are many types of fluid collections that are termed cystic neoplasms.  However, the vast majority of these fluid collections will not develop into cancer because they are so slow growing.  These cysts have names such as intraductal papillary neoplasms (IMPN), mucinous neoplasms (MCN) and serous cystadenoma (SCA).  Occasionally, these cysts will need to be removed operatively when they are first diagnosed.  However, most do not need to be removed.  It is important, however, that if you are found to have one of these types of fluid collections, that it be followed carefully by your physician to make sure it does not transform into a malignancy. Other types of fluid collections, such as inclusion cysts, are benign and do not need to be removed.

Diagnosis of Fluid Collections

The most important diagnostic consideration for fluid collections is a good clinical history to be taken by your physician.  For example, in patients who have had acute pancreatitis and developed a fluid collection, the most likely type of fluid collection is a pseudocyst or WOPN. Your physician usually will want to take a picture of the fluid collection either with a computed tomography (CT) or Magnetic Resonance Imaging (MRI) scan.  Both are painless and non-invasive, and will generally be a good indicator of the type of collection present. Occasionally, your physician may want to evaluate the collection with a procedure called an endoscopic ultrasound (EUS).  This procedure, in which an endoscope is passed via the mouth while the patient is sedated, allows a specialist to evaluate the cyst with very good accuracy by using an internal ultrasound device.  The device also allows for sampling of the fluid collection, which is often helpful to determine its cause.  There are also a collection of blood and fluid tests that can be helpful in determining the cause of the fluid collection.

Treatment of Fluid Collections

The type of treatment recommended will depend on the type of fluid collection.  For benign fluid collections like psudocysts or WOPN, the treatment is usually observation unless symptoms develop.  If symptoms develop, endoscopic or operative drainage is generally recommended. For fluid collections that have the opportunity to transform into cancer, most of these collections can be watched closely without intervention.  Occasionally, however, depending on the type of collection, its size, the underlying characteristics of the patient, and the rate at which the collection is growing, operative intervention may be recommended.  It is important to discuss all management options with your physician prior to proceeding with any operative resection.

Conclusions

Pancreatic fluid collections are very common and the vast majority will never develop into any serious medical issue.  However, it is important that they be accurately diagnosed and if any worrisome features are noted, they be removed.  Specialists such as gastroenterologists, pancreatic surgeons, or medical oncologists should be consulted in virtually all instances when a pancreatic fluid collection is discovered. Contributed by: Timothy B. Gardner, MD Director, Pancreatic Disorders Dartmouth-Hitchcock Medical Center Assistant Professor of Medicine Dartmouth Medical School