2. HISTORY
A 45 year old alcoholic presents to the OPD with a mass in the upper
abdomen. He had been admitted at a hospital in his hometown 2
months ago, with severe upper abdominal pain and vomiting, at which
time he was advised to quit alcohol. On examination, there is a 6x8
cm mass in the epigastric region, not moving with respiration. It is firm,
non-tender, with a resonant note on percussion.
3. PSEUDOCYST
A pseudocyst is a collection of amylase-rich fluid enclosed in a wall
of fibrous or granulation tissue.
Pseudocysts typically arise following an attack of acute pancreatitis,
but can develop in chronic pancreatitis or after pancreatic trauma.
Formation of a pseudocyst requires 4 weeks or more from the onset
of acute pancreatitis.
They are often single but, occasionally, patients will develop multiple
pseudocysts.
If carefully investigated, more than half will be found to have a
communication with the main pancreatic duct.
4. INVESTIGATION
A pseudocyst is usually identified on ultrasound or a CT scan.
It is important to differentiate a pseudocyst from an acute fluid collection or an
abscess;
the clinical scenario and the radiological appearances should allow that
distinction to be made.
Occasionally, a cystic neoplasm may be confused with a chronic pseudocyst.
EUS and aspiration of the cyst fluid is very useful in such a situation.
The fluid should be sent for measurement of CEA levels, amylase levels and cytology.
Fluid from a pseudocyst typically has a low CEA level
**Levels above 400 ng/mL are suggestive of a mucinous neoplasm.
Pseudocyst fluid usually has a high amylase level, but that is not diagnostic,
as a tumour that communicates with the duct system may yield similar findings
5. Cytology typically reveals inflammatory cells in pseudocyst fluid.
If there is no access to EUSthen percutaneous FNA is
acceptable (just aspiration, not percutaneous insertion of a drain).
ERCP and MRCP may demonstrate communication of the cyst with
the pancreatic duct system, demonstrate ductal anomalies or
diagnose chronic pancreatitis and thus help in planning treatment.
6. MANAGEMENT
Pseudocysts will resolve spontaneously in most instances, but
complications can develop.
Pseudocysts that are less likely to resolve spontaneously
thick-walled or large (over 6 cm in diameter),
have lasted for a long time (over 12 weeks) or
have arisen in the context of chronic pancreatitis
but these factors are not specific indications for intervention.
Therapeutic interventions are advised only if
the pseudocyst causes symptoms,
if complications develop
a distinction has to be made between a pseudocyst and a tumour.
7. DRAINING A PSEUDOCYST
1. Percutaneous drainage to the exterior under radiological guidance should
be avoided.
It carries a very high likelihood of recurrence.
Moreover, it is not advisable unless one is absolutely certain that the cyst is not
neoplastic and that it has no communication with the pancreatic duct (or else a
pancreaticocutaneous fistula will develop).
2. A percutaneous transgastric cystgastrostomy can be done under imaging
guidance, and a double-pigtail drain placed with one end in the cyst cavity and
the other end in the gastric lumen.
This requires specialist expertise but, in experienced hands, the recurrence rates are
no more than 15 per cent.
8. 3. Endoscopic drainage usually involves puncture of the cyst through the
stomach or duodenal wall under EUS guidance, and placement of a tube
drain with one end in the cyst cavity and the other end in the gastric lumen.
The success rates depend on operator expertise.
4. ERCP and placement of a pancreatic stent across the ampulla may help
to drain a pseudocyst that is in communication with the duct.
5. Surgical drainage involves internally draining the cyst into the gastric or
jejunal lumen.
Recurrence rates should be no more than 5 per cent, and this still remains the
standard against which the evolving radiological and endoscopic approaches are
measured.
The approach is conventionally through an open incision, but laparoscopic
cystgastrostomy is also feasible.
Pseudocysts that have developed complications are best managed
surgically