Based on these findings we considered that the patient was suffering from a symptomatic pancreatic pseudocyst two years after an episode blunt trauma. The unilocular pseudocyst was located in the body of the pancreas in contact with the pancreatic duct. It was less than 6 cm in size. This patient was a candidate for endoscopic transpapillary drainage to manage his pseudocyst.

Endoscopic retrograde cholangiopancreatography (ERCP) was performed on the patient. It showed stenosis of the common bile duct. The pancreatic duct pseudocyst was catheterized and opacified. Opacification of the pseudocyst was observed (Figure 2). A pancreatic sphincterotomy was performed followed by insertion of a 5 French x 5 cm plastic stent in the proximal end of the pseudocyst. Pancreatic fluid drainage showed at the distal end of the stent (Figure 3). The bile duct was found to be normal.

Figure 2. ERCP. Pancreatography. Hydrophilic guide wire inside the pseudocyst.

Figure 3. ERCP. Pancreatography. 5Fr stent draining the pseudocyst.

At the two week check-up after stent insertion the patient showed significant clinical improvement with decreased pain and increased oral tolerance. The abdominal ultrasound showed evidence of diminution of the pseudocyst’s size to 2cm x 1cm x 1cm. We decided to remove the pancreatic stent.

Additional tests were conducted. 30 days after stent insertion. The patient had none of the symptoms for which he had initially been referred. The cyst could not be seen in a sonogram. At the 60 day follow up the patient remained asymptomatic.

DISCUSSION

A pancreatic pseudocyst is a collection of fluid which is rich in amylase and other pancreatic enzymes. It is which is covered by a wall of fibrous tissue which is not surrounded by epithelium (1). A pancreatic pseudocyst is caused by disruption of the pancreatic duct followed by an increase in ductal pressure caused by stenosis, stones, precipitation of proteins which block the pancreatic duct proximal, or as the result of pancreatic necrosis after an episode of acute pancreatitis. They connect to the pancreatic duct either directly or through the pancreatic parenchyma (2).

The main causal factors in pancreatitis are alcoholism, biliary etiology, and then abdominal trauma (3).

There are several classifications of pancreatic pseudocysts. One of them is the Nealon and Walser classification system which is based on the anatomy of the pancreatic duct (4). Type I indicates a normal duct with no connections to the cyst. Type II is a normal duct connected to the cyst. Type III indicates a duct with stenosis that is not connected to the cyst. Type IV indicates a duct with stenosis that is connected to the cyst. Type V indicates a duct with complete obstruction. Type VI indicates chronic pancreatitis without any connection between duct and cyst. Type VII indicates chronic pancreatitis with the duct connected to the cyst. This classification can also provide a guide to physicians about the best type of approach for the treatment of pseudocysts (surgical, endoscopic and/or percutaneous drainage).

More than 50% of pseudocyst cases resolve spontaneously, consequently it is considered that the initial management of patients should consist of hydration, analgesics and antiemetics (5-10). The two main factors determining spontaneous regression of pancreatic pseudocysts are size and time of evolution after diagnosis (11). Significant numbers of pseudocysts of less than 4cm resolve spontaneously. Moreover, they have lower complication rates than do larger cysts (1, 6-11). In relation to time, acute pseudocysts have a higher rate of spontaneous regression in the first 6 weeks after observation than do pseudocysts which have persisted more than 7 weeks after diagnosis (8%). Relative indications for whether or not spontaneous regression will occur include pseudocyst sizes larger than 4 cm and no changes in size, morphology, or progression after an observation period of 6 weeks (1).

Symptomatic pseudocysts are those with complications. Complications including infections, hemorrhaging, compression of large vessels, obstruction of gastric outflow tract and obstruction of biliary duct are the main indications for drainage. The choice of management depends on local experiences. However, endoscopic treatment is preferred because it is a less invasive method than surgery. It avoids the need for external drainage and has a high long-term success rate. Transpapillary drainage can be performed with ERCP or direct drainage is possible through the stomach or duodenal walls. Endoscopic ultrasonography (EUS) is considered to be the test of choice for determination of the size and location of the pseudocyst and for measurement of wall thickness.

Transgastric or transduodenal endoscopic drainage is indicated in cases of simple mature pseudocysts where there has been no disruption of the pancreatic duct. Ideally they should be larger than 5 cm and be producing compression in the gastric or duodenal wall. The distance between the pseudocyst and the gastric or duodenal wall duodenal should be less than 1 cm (11). This distance can be measured adequately by EUS.

Transpapillary drainage through pancreatic stent insertion is indicated when the pseudocyst is connected to the pancreatic duct. It can be successful for patients with pancreatic duct disruption (3). Individual reports have found that the pancreatic pseudocyst is connected to the pancreatic ductal system in 22% to 57% of cases (7, 9).

No randomized prospective studies have been published which would provide answers to questions about the necessary duration of treatment with pancreatic duct stents, the optimal timing of stent insertion, or how often stents should be changed.

Barther et al ereported that, in a number of cases, the duration of therapy depends on the pseudocyst regression time. The mean time in published studies was 4.4 months (7). Catalano et al. performed a study on 37 patients. For 17 patients, resolution was immediate. 16 patients were free of recurrences at 37 months. The stents were replaced every 6-8 weeks if the pseudocysts remained unresolved (8).

In general, when the pseudocyst is less than 6 cm, and it is connected to the pancreatic duct, there is a better than 90% success rate with complete resolution of the lesion through transpapillary drainage (10).

At present, transcutaneous drainage is indicated only as an emergency procedure in cases of acute retention of fluid or when cysts are infected. This is because this procedure had a rate of recurrence greater than 70% and because formation of percutaneous fistulas is a common complication.

The patient we are reporting on had a pseudocyst that was 4 cm in diameter and was connected to the main pancreatic duct. After insertion of the stent the lesion resolved in 4 weeks. It was completely resolved, without symptoms and without recurrence, by the 60 day check-up.

Our conclusion is that the current trend in managing pancreatic pseudocysts with minimally invasive therapeutic and endoscopic procedures is superior to surgical procedures in terms of morbidity and mortality rates, however these procedures cannot always be performed. In making decisions about the treatment of pancreatic pseudocyst it is important to note that about 50% do not require intervention and resolve spontaneously with observation and clinical follow-up (10).

The selection of a technique for pseudocyst drainage depends on the experience of the group treating the pseudocyst. Transpapillary drainage is a safe and highly efficient option when the lesion is less than 6 cm, and it is connected to the pancreatic duct.

References

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