"A patient with a known history of previous pancreatitis presents to you complaining of abdominal discomfort and has an elevated amylase level. You do an ultrasound and find 3-4cm pancreatic pseudocyst; what would you do?"
Most pseudocysts in the pancreas develop during the course of chronic pancreatitis and not immediately following acute pancreatitis. Everybody agrees that non-symptomatic cysts less than 4cm in size should just be followed by serial ultrasound. Once the pseudocyst reaches the size of 5-6cm or becomes significantly symptomatic (pain, obstructive symptoms, etc.) something has to be done.
A safe approach is described here:
On the oral board exam., you should always mention your attempts/concern about ruling out malignancy within the pancreatic cyst ( solid elements on CT, FNA results... etc).
Do ERCP (check if the pseudocyst is communicating with the pancreatic duct - 15% of cases - or not). The recent changes in treating pancreatic pseudocyst are basically most helpful in treating non-communicating, minimally symptomatic, more than 4cm in size pseudocysts. In this case needle aspiration under CT guidance can be done and repeated as needed up to 3-4 times (some centers leave a catheter in the cyst cavity and change it frequently to prevent the high incidence of infection). If the cyst persists or becomes significantly symptomatic, surgical internal drainage is indicated.
If the pseudocyst is a communicating cyst, significantly symptomatic and larger than 6cm, surgical internal drainage is indicated, as long as it has a matured wall (at least 6 weeks old) and not complicated (not infected or bleeding and malignancy has been ruled out by F.S. if necessary). This is accomplished by Roux-en Y cystojejunostomy which is the procedure of choice in most centers or distal pancreatectomy (if the cyst is in the pancreatic tail) or rarely cystoduodenostomy (if it is deep in the head of the pancreas in close association with the duodenum) or cystogastrostomy.
Recently, endoscopic internal drainage of communicating cysts associated with partial pancreatic duct disruption (treated by trans ampullary stent drainage) or endoscopic cyst-enterostomy for cysts causing visible impingement on the gastric or duodenal wall have become reasonable non-surgical options in selected cases.
If the pseudocyst is infected (by FNA), only external drainage should be performed, whether percutaneously or surgically as described in the pancreatic abscess chapter. Should a pancreatic cyst bleed (usually by erosion into the splenic or gastroduodenal artery branches), the diagnosis should be suspected with sudden onset of pain and sometimes even shock. A CT scan with IV contrast is diagnostic. If the patient is reasonably stable, he/she should be sent immediately to radiology for an angiogram and embolization of the bleeding vessel. If this fails or the patient is unstable, immediate laparotomy should be done. The offending vessel should be ligated first, then the cyst is opened and packed immediately, then careful suture ligation of the bleeders from within the cyst wall is performed and the cyst is externally drained.
It should be remembered that a dramatic hemorrhage in a pseudocyst patient can be due to one of three pathologies:
Bleeding into the cyst (erosion into one of the pancreatic vessels).
Bleeding into the bowel (erosion into bowel wall, mainly the colon, duodenum or stomach).
Bleeding from gastric varices, secondary to splenic vein thrombosis (in this case splenectomy is life saving).
That is why an arteriogram (or more recently triple phases CT angiogram) whenever possible, should be performed prior to the surgery in these situations.
Pancreatic true cysts
You should suspect true cysts when the hx. is not suggestive of pseudocyst (non-alcoholic patient with biliary problems and no previous hx. of pancreatitis... etc.).
Pancreatic cysts could be true cyst (congenital, dermoid, parasitic...) or benign cystic tumor (serous or mucinous cystadenoma) or malignant cystic tumor (cystadenocarcinoma) or other rare types.
Mucinous cysts have higher malignant potentials than serous cysts and tend to be located at the body and tail of the pancreas as opposed to the serous cysts found mostly at the head of the pancreas.
True cysts tend to have sharply circumscribed and encapsulated on CT scan with multiple septations and calcifications (central in serous type and peripheral in mucinous type).
Whenever the examiner suggest to you the possibility of true cyst, ask for FNA and send the aspirate for analysis of the following:
CEA level (elevated in mucinous cyst, low in serous and pseudocyst)
CA 125 (elevated in malignant cyst, low in pseudocyst, variable in benign true cyst)
Amylase and Lipase (high in pseudocyst, low in true cyst)
Viscosity (high in mucinous cyst, low in serous and pseudocyst)
Percutaneous cytology (can identify malignant cells)
Percutaneous wall biopsy (lack of epithelial lining in pseudocyst, it can also differentiate between serous and mucinous lining in true cysts).
Treatment of malignant cysts depends on total surgical extirpation and aggressive approach is warranted even in the presence of mets. 5 years survival of mucinous cystadenocarcinoma is greater than 60%.