A pancreatic pseudocyst is defined as an encapsulated fluid collection with a well-defined inflammatory wall with minimal or no necrosis. The diagnosis cannot be made prior to 4 wk after the onset of pancreatitis. The clinical presentation is often nonspecific, with abdominal pain being the most common symptom. If a diagnosis is suspected, contrast-enhanced computed tomography and/or magnetic resonance imaging are performed to confirm the diagnosis and assess the characteristics of the pseudocyst. Endoscopic ultrasound with cyst fluid analysis can be performed in cases of diagnostic uncertainty. Pseudocyst of the pancreas can lead to complications such as hemorrhage, infection, and rupture. The management of pancreatic pseudocysts depends on the presence of symptoms and the development of complications, such as biliary or gastric outlet obstruction. Management options include endoscopic or surgical drainage. The aim of this review was to summarize the current literature on pancreatic pseudocysts and discuss the evolution of the definitions, diagnosis, and management of this condition.

According to the Atlanta classification an acute pseudocyst is a collection of pancreatic juice enclosed by a wall of fibrous or granulation tissue, which arises as a consequence of acute pancreatitis or pancreatic trauma, whereas a chronic pseudocyst is a collection of pancreatic juice enclosed by a wall of fibrous or granulation tissue, which arises as a consequence of chronic pancreatitis and lack an antecedent episode of acute pancreatitis. It is generally agreed that acute and chronic pseudocysts have a different natural history, though many reports do not differentiate between pseudocysts that complicate acute pancreatitis and those that complicate chronic disease. Observation--"conservative treatment"--of a patient with a pseudocyst is preponderantly based on the knowledge that spontaneous resolution can occur. It must, however, be admitted that there is substantial risk of complications or even death; first of all due to bleeding. There are no randomized studies for the management protocols for pancreatic pseudocysts. Therefore, today we have to rely on best clinical practice, but still certain advice may be given. First of all it is important to differentiate acute from chronic pseudocysts for management, but at the same time not miss cystic neoplasias. Conservative treatment should always be considered the first option (pseudocysts should not be treated just because they are there). However, if intervention is needed, a procedure that is well known should always be considered first. The results of percutaneous or endoscopic drainage are probably more dependent on the experience of the interventionist than the choice of procedure and if surgery is needed, an intern anastomosis can hold sutures not until several weeks (if possible 6 weeks).

To test a hypothesis that definitive management of pseudocyst associated with chronic pancreatitis is predicated on addressing pancreatic ductal anatomy.

The authors have previously confirmed the impact of pancreatic ductal anatomic abnormalities on the success of percutaneous drainage of pancreatic pseudocyst. The authors have further defined a system to categorize the pancreatic ductal abnormalities that can be seen with pancreatic pseudocyst. The authors have published, as have others, the usefulness of defining ductal anatomy when managing pancreatic pseudocysts associated with chronic pancreatitis.

Beginning in 1985, all patients with pseudocyst who were candidates for intervention (operative, percutaneous, or endoscopic) have undergone endoscopic retrograde cholangiopancreatography (ERCP). An associated diagnosis of chronic pancreatitis was established by means of ERCP findings. Patients were candidates for longitudinal pancreaticojejunostomy (LPJ) if they had a pancreatic ductal diameter greater than 7 mm. In a nonrandomized fashion, patients were managed with either combined simultaneous LPJ and pseudocyst drainage or with LPJ alone.

Two hundred fifty-three patients with pseudocyst have been evaluated. Among these there have been 103 patients with chronic pancreatitis and main pancreatic duct (MPD) dilatation (>7 mm). Among these 103 patients, 56 underwent combined LPJ/pseudocyst drainage and 47 had LPJ alone. Compared to combined LPJ/pseudocyst drainage, the patients undergoing LPJ alone had a shorter operative time, slightly less transfusion requirement, slightly reduced length of hospital stay, and slightly reduced complication rate. Long-term pain relief was achieved in 90%, and pseudocyst recurrence was less than 1%. Rates of each of these long-term outcomes were nearly incidental among the two groups.

Ductal drainage alone (LPJ) is sufficient in patients with chronic pancreatitis (MPD > 7 mm) and an associated pseudocyst. Simultaneous drainage of pseudocyst is not necessary.

This article reviews the history of and the authors' experience with endoscopic management of pancreatic pseudocysts. Discussion includes pseudocyst enterostomy and results, the transpapillary method, complications, endoscopic versus surgical and percutaneous therapy, and drainage of infected pseudocysts and pancreatic necrosis.

Pancreatic pseudocysts may produce pain, or biliary or duodenal obstruction. Those over 6 cm in diameter or associated with chronic pancreatitis are unlikely to resolve and usually require intervention. There are a number of treatment modalities available and this paper reviews the role of endoscopic drainage.

All articles and case reports quoted on Medline (National Library of Medicine, Washington DC, USA) containing the text words 'endoscopy' and 'pseudocyst', and citations from these references were reviewed.

Endoscopic drainage is technically feasible in around 50 per cent of pancreatic pseudocysts associated with chronic pancreatitis. Successful drainage occurred in 82-89 percent. The major complication is bleeding which required surgery for control in 5 per cent of procedures. One death attributable to the procedure has been reported. Recurrence rates range from 6 to 18 per cent with up to 4 years' follow-up. As in open surgery, recurrence is highest with drainage via the stomach.

Endoscopic drainage provides a minimally invasive approach to pseudocyst management, with success and recurrence rates similar to those of open surgery but with lower morbidity and mortality rates. It should be considered the treatment of choice for pseudocysts less than 1 cm thick which bulge into the stomach or duodenum, or for those which communicate with the main pancreatic duct.

Endoscopic treatment of pancreatic pseudocysts via cystenterostomy has been recognized as a successful treatment option in carefully selected patients. Pancreatic transpapillary stenting as an alternative treatment option in patients with pancreatic pseudocysts directly communicating with the main duct has received little consideration. The aim of the current study was to assess the safety and utility of transpapillary pancreatic endoprosthesis in the treatment of communicating pseudocysts.

Twenty-one patients underwent placement of 33 transpapillary endoprostheses for the treatment of symptomatic pancreatic pseudocysts. All pseudocysts communicated with the main pancreatic duct and ranged in size from 3 to 9 cm (mean 6 cm). Eight patients had associated pancreatic duct strictures.

Stent placement was successful in all cases: 13 directly into the pseudocyst, 8 beyond the stricture but not into the pseudocyst. Initial resolution of pseudocysts was seen in 17 patients, with 16 patients free of pseudocyst recurrence at mean follow-up of 37 months. All patients with associated strictures were treated successfully. Factors predictive of success included presence of strictures, size of pseudocyst greater than or equal to 6 cm, location in the body of the pancreas, and duration of pseudocyst less than 6 months. Complications included one episode of mild pancreatitis.

Endoscopic treatment of symptomatic pancreatic pseudocysts with ductal communication by transpapillary pancreatic duct stenting is a safe, effective modality and should be considered a first line therapy.

To evaluate the frequency of multiple pancreatic cysts, the likelihood of preoperative diagnosis, and therapeutic outcome, we retrospectively reviewed the records of 157 patients who underwent operation for pancreatic pseudocysts at 2 institutions between 1970 and 1992. Multiple pseudocysts were found in 29 (18.5%). The 8 women and 21 men ranged in age from 21 to 79 years. The etiology was alcohol abuse in 15 (52%), biliary tract disease in 6 (21%), alcohol abuse and biliary tract disease in 3 (10%), and a variety of other causes in the remaining 5 (17%). There was no difference in age, sex, race, etiology, or presenting signs and symptoms between patients with single pseudocysts and those with multiple cysts. Serum amylase levels were significantly higher in patients with multiple cysts compared to those with single cysts (P < 0.05). Computed tomography accurately demonstrated the extent of disease in 20 of 25 patients (80%), while 1 or more cysts were missed in 5 (20%). The mean number of cysts per patient was 2.7, with a range of 2 to 5. Average pseudocyst diameter was 7.8 cm, with a range from 3 to 20 cm. Multiple internal drainage procedures were performed in 19 patients, a combination of internal and external drainage in 6, external drainage in 1, and resection of multiple cysts in the tail in 2. There was no operative mortality. With a mean follow up of 38.5 months, only 1 recurrent pseudocyst has been found. There were six attempts at percutaneous drainage in six patients. Two of these patients were referred to our institution following failure of percutaneous drainage at other hospitals. Three other patients had residual symptomatic pseudocysts following percutaneous drainage at our hospitals and then underwent multiple internal drainage. The sixth patient refused operative drainage despite the persistence of residual symptomatic pseudocysts after attempted percutaneous drainage. The incidence of multiple pseudocysts (18.5%) is higher than previously reported. There is no difference in the clinical features of patients with single versus multiple pseudocysts. Patients with multiple cysts have higher serum amylase levels. Preoperative computed tomography underestimated the number of cysts in 20% of patients. Careful intraoperative exploration is still needed to avoid missing multiple pseudocysts. Internal drainage is the preferred therapy. A thorough search for multiple cysts at the initial operation should eliminate one potential cause for pseudocyst recurrence.

The records of 92 patients with symptomatic pancreatic pseudocysts referred for surgical management over a 27-year period were retrospectively reviewed to compare outcome in 42 patients managed with operative internal drainage procedures (group I) with that in 52 patients managed with computed tomography-directed percutaneous catheter drainage (PCD) (group II). The two groups were similar for patient age, sex, pseudocyst location, and cause. The frequency of antecedent pseudocyst-associated complications was less in group I (16.7 versus 38.5%, p less than 0.05). Seven group I patients and four group II patients had major complications (16.7 versus 7.7%, not significant). Group II mean duration of catheter drainage was 42.1 days, and the drain track infection rate was 48.1%. The frequency of antecedent operative cyst drainage was similar (14.2 versus 13.5%), as was the frequency of subsequent operations for complications related to chronic pancreatitis (9.5 versus 19.2%, not significant). Mortality rate was greater in group I (7.1% versus 0%, p less than 0.05). Pseudocysts can be effectively managed either by open operation with internal drainage or by PCD. Drawbacks of PCD include the controlled external pancreatic fistula and the risk of drain track infection. Percutaneous catheter drainage has the following advantages: (1) low mortality rate, (2) does not require a major operation, (3) does not violate the operative field in cases when subsequent retrograde duct drainage procedures are required. Neither PCD nor internal drainage is definitive, and with either technique subsequent correction of underlying pancreatic pathology may be necessary.

In the treatment of pancreatic pseudocysts, percutaneous and endoscopic drainage have, in certain cases, become alternatives to surgery. However, each treatment modality carries risks of complications and recurrences that may be minimized by the appropriate allocation of therapy. This article proposes the use of an endoscopic retrograde cholangiopancreatography (ERCP)-based algorithm as a means to allocate pseudocyst therapy based on the findings of pancreatic duct obstruction or pseudocyst communication. To evaluate this algorithm, the records of a series of patients with pancreatic pseudocysts seen at Duke University Medical Center from 1984 to 1990 were reviewed. Of 102 patients, 73 had symptomatic pseudocysts that required treatment. Forty of the 69 elective interventions were preceded by ERCPs and retrospectively applied to the algorithm. The number of adverse outcomes (treatment failures + complications) of the group that followed the algorithm was 3 of 26 (12%), while the number of adverse outcomes of the group that did not follow the algorithm was 6 of 14 (43%) (p less than 0.04 by Fisher's exact test). These two subgroups were similar in all other characteristics examined. Therefore, this ERCP-based algorithm may be used to allocate pseudocyst treatment; however, a prospective trial is necessary to prove its efficacy.

Pancreatic pseudocysts in 83 patients were classified according to clinical and radiographic criteria. Group I (45 patients) had acute, 'post-necrotic' pseudocysts with normal pancreatic duct anatomy and rarely duct-pseudocyst communication. Percutaneous drainage was curative in all patients in whom it was used. Group II (26 patients) included 'post-necrotic' pseudocysts developing in patients already suffering from chronic pancreatitis. The pancreatic duct was diseased but not strictured, and duct-pseudocyst communication was often present. Percutaneous drainage is possible for such patients but it may have to be prolonged; surgical internal drainage was usually successful. Group III (12 patients) had chronic 'retention' pseudocysts. The pancreatic duct was grossly diseased and strictured and duct-pseudocyst communication was present in all cases. Percutaneous drainage is contraindicated and surgical internal drainage has a high recurrence rate. Operative procedures in this group should address the specific ductal pathology. An improved classification of pseudocysts could help the surgeon to choose the most appropriate form of treatment.

Pancreatic fluid collections (PFC) can be drained surgically or nonsurgically with endoscopic or radiologic techniques. To define subgroups of patients with PFC who would benefit from the new modalities, we reviewed a period (1977 to 1990) during which both surgical and nonsurgical invasive techniques were available. Patients with phlegmon or necrosis at initial diagnosis were excluded. Sixty-five patients (35 male, 30 female) underwent 1 or more drainage procedures. A mean postprocedure follow-up of 10.2 months was available for 59 patients. Initial management was nonsurgical in 80% of patients. Procedures in patients with follow-up comprised invasive nonsurgical drainage (n = 25), invasive nonsurgical drainage plus surgery (n = 22), and surgery only (n = 12). Results for each group, respectively, were: morbidity, 20%, 20%, and 24%; mortality, 8%, 5%, and 0%; and successful drainage, 92%, 82%, and 83%. The choice of management appeared to be based on etiology and radiologic characteristics. Patients with nonalcohol- and nonbiliary-associated pancreatitis without a radiographically defined wall were more common in the invasive nonsurgical group and were successfully treated without surgery. Nonsurgical invasive techniques are efficacious in the treatment of PFC in this subgroup of patients.

Acute pain in the upper abdomen in a patient recovering from pancreatitis or abdominal trauma may herald a pancreatic pseudocyst. Although small cysts resolve spontaneously, those larger than 6 cm across usually require treatment to prevent such complications as rupture into adjacent structures and infection. The authors describe operative and nonoperative treatment methods and the success reported with each.

Fifty patients underwent ultrasonically guided percutaneous drainage (US-GPD) either with needle aspiration or catheter drainage. The procedures resulted in 70% complete recovery, 20% partial success and 10% of failures. The same patients were followed with clinical examination and sonography for a mean time of 36.3 months (minimum follow-up: 12 months). During the follow up period, 10 relapses occurred and one patient, considered for surgery after partial percutaneous treatment of a pyogenic liver abscess, recovered completely under conservative treatment. An analysis of the factors potentially related to the recurrence was made. It was found that one-step needle aspiration of abdominal abscesses and percutaneous treatment of chronic pancreatic pseudocysts are more prone to relapses. We conclude that US-GPD is an efficacious therapy for abdominal fluid collections, but an adequate drainage technique and a careful selection of the patients is crucial to avoid the possibility of relapse.

We describe a modified ultrasound-guided transgastric drainage technique for pancreatic pseudocysts. Using a water-filled stomach to improve visualization, we have successfully drained pseudocysts in ten patients. This report also describes the use of a stiffening cannula to assist transgastric catheter placement. We emphasize the value of constant real-time tracking of the dilator and guidewire to ensure correct positioning of the drainage catheter.

Surgical intervention in acute pancreatitis may have varied goals. Early laparotomy may be required for diagnostic purposes. There is, however, no convincing evidence that attempts to reduce the morbidity of severe pancreatitis by early operative pancreatic drainage, early formal pancreatic resection, or early biliary procedures have been effective. In fact, they may be harmful. Peritoneal lavage by catheter induced under local anesthesia may ameliorate early cardiovascular and respiratory complications in some patients. Preliminary experience suggests that early operative debridement of devitalized pancreatic tissue with postoperative lavage may be helpful in selected patients. Patients with infections of devitalized pancreatic or peripancreatic tissue require operative debridement and drainage or packing. Other complications such as colonic necrosis or pseudocysts also require operative treatment. Rarely do patients require operation to relieve protracted pancreatitis. Patients with gallstone-associated pancreatitis should usually undergo surgical correction of their cholelithiasis as soon as their pancreatitis has subsided.

Chronic alcoholism is the etiologic factor initiating most instances of chronic pancreatitis and its complications in the United States of America. The goal of operative intervention is to relieve incapacitating abdominal and back pain, while preserving as much endocrine and exocrine function as possible. Ultrasound and computed tomography scans are helpful for the identification of gross anatomical changes in the pancreas, but endoscopic retrograde cholangiopancreatography is critical for the precise delineation of pancreatic ductal anatomy. In patients who exhibit dilation of the pancreatic duct secondary to single or multiple sites of obstruction, pancreatic ductal drainage will provide complete or significant relief of pain in greater than 80% of patients. Side-to-side pancreaticojejunostomy has evolved as the operation which permits the widest drainage of the entire pancreatic ductal system. Although, initially, it was hoped that pancreatic exocrine and endocrine function would improve or stabilize after pancreatic ductal drainage, follow-up studies show that the destructive process in the pancreatic islets and acinar cells initiated by chronic alcoholism continues during the years after operation with an increasing incidence of diabetes and steatorrhea. Late mortality is primarily related to continued alcoholism and death secondary to alcohol-(and-smoking-) associated diseases. Correction of coexistent complications secondary to chronic pancreatitis including pseudocyst and biliary and/or duodenal obstruction should be considered at the time of pancreatic ductal drainage.

Experience with patients with pancreatic pseudocysts has led the authors to the hypothesis that preoperative evaluation of the pancreatic and bile ducts by ERCP will define those patients who may be inadequately treated by pseudocyst drainage alone without attention to associated pancreatic and biliary ductal abnormalities. In patients with certain ductal abnormalities, the pseudocyst operation was combined with a definitive operative drainage of the pancreatic duct and/or of the biliary tree where appropriate. A prospective evaluation of routine preoperative ERCP was undertaken over a 36-month period in all patients scheduled for operative treatment of pseudocyst of the pancreas. From an initial group of 44 patients with pseudocysts, three patients who had spontaneous regression of the pseudocyst were excluded. ERCP was successful in 39 of the remaining 41 patients. Among 41 operated patients, 24 were admitted with a diagnosis of pseudocyst that arose after an episode of acute pancreatitis, and 17 had chronic pancreatitis with pseudocyst. Nine patients, initially assumed to have acute pancreatitis, were recognized to have chronic pancreatitis on the basis of ERCP findings. Communication with the main pancreatic duct (MPD) was demonstrated in 18 of 41 pseudocysts, and the rate of communication was similar in patients with acute and chronic pancreatitis. Dilatation of the MPD was seen in 23 of 41 patients and was associated with chronic pancreatitis in 21. Dilatation of the common bile duct was found in 12 patients with chronic pancreatitis. The operative plan was altered by ERCP findings in 24 of 41 patients; 22 of the 24 patients had chronic pancreatitis. There were no complications of ERCP. These data suggest that ERCP should be performed in all patients with pseudocysts to establish correct diagnosis and to allow optimal choice of operation.

Review of the diagnosis and treatment of patients with pancreatic pseudocysts over the past 8 years has led us to three conclusions regarding controversial aspects of their treatment. We found that patients who present with chronic pseudocysts can be identified with the help of computerized axial tomography and promptly undergo successful internal drainage, whereas patients with acute peripancreatic fluid secondary to pancreatitis can be observed expectantly with a 43 percent frequency of spontaneous resolution. Patients with infected pancreatic pseudocysts can be safely drained internally. The most common cause of extrahepatic biliary obstruction in this group of patients with pancreatic pseudocysts was stricture due to pancreatitis and fibrosis, not extrinsic compression.

A biochemical evaluation was performed on plasma from eight patients developing a pancreatic pseudocyst during acute pancreatitis attacks and from six patients with a known pseudocyst. Patients developing an acute pancreatic pseudocyst had high levels of activated trypsin in complex with alpha 1-protease inhibitor, together with a probable activation of the kinin, complement, coagulation and fibrinolytic systems. Profound changes were also seen in several protease inhibitors, indicating consumption of the inhibitors. The changes did, however, not differ from those seen in severe acute pancreatitis attacks in which no pseudocyst developed. Patients with chronic pancreatic pseudocysts had biochemical changes similar to those seen in moderate pancreatitis attacks, without any overt cascade system activation. At convalescence, however, these patients had biochemical signs of leakage from the pancreas and an ongoing proteolytic activity.

A small fraction of pancreatic cysts are neoplastic rather than inflammatory in origin. Failure to recognize the true nature of a neoplastic cyst will lead to an incorrect treatment strategy. This is a report of eight patients whose cystic neoplasms were misdiagnosed and maltreated. Five of the eight tumors proved to be malignant. Five were drained by anastomosis to a viscus and one by aspiration; drainage was recommended for the other two. Treatment by drainage led to complications (persistent painful gastric ulcer, infection in the cysts), growth of new cysts, no cures, but missed opportunities to cure cancer. Three patients with no metastases at first operation had metastatic spread to the liver, omentum, or lungs at reoperation. In three of the five cases initially treated by cystenterostomy (including one cancer), subsequent resection was possible and probably curative. One cystadenocarcinoma was watched for 3 years before apparently curative resection. Guidelines based on serum and cyst amylase levels, morphologic appearance, angiography, pancreatography, and biopsy are given for the purpose of differentiating inflammatory cysts from neoplastic cysts of the pancreas. Confusion of these entities should not occur, but errors can often be corrected.

A review of 115 patients with pancreatic pseudocysts treated surgically between 1976 and 1984 showed four patterns of presentation: pseudocyst alone, pseudocyst and acute pancreatitis, acute pancreatitis alone, or neither apparent on hospital admission. These patterns of presentation were associated with differences in the clinical course and ultimate surgical outcome of each group of patients. Emergency procedures greatly increased the morbidity and mortality of surgery for pseudocysts. A preoperative delay for pseudocyst maturation was expected to decrease the morbidity and mortality of elective pseudocyst drainage, but no benefit was found either for the series as a whole or for any subgroup. We conclude that an arbitrary preoperative delay for pseudocyst maturation (in the absence of acute pancreatitis) exposes patients to the risks of preoperative complications, increases the expense of care for pancreatic pseudocysts, and fails to improve surgical outcome.

Preoperative ERCP was performed on 39 patients treated surgically for pancreatic pseudocysts from 1970 to 1982 at the Minneapolis Veterans Administration Medical Center. ERCP-related sepsis was rare (4 percent of patients) and only occurred when surgery was delayed for more than 24 hours. The primary benefit of preoperative ERCP was to provide detailed information on pancreatic and biliary ductal anatomic characteristics other than those specifically related to the pancreatic pseudocyst. These data influenced the choice of operation in 49 percent of the patients. Specific preoperative surgical planning was facilitated and intraoperative pancreatography and cholangiography were obviated. Major postoperative complications occurred in 21 percent of the patients (0 percent mortality) but none were considered to be related to preoperative ERCP. ERCP before operation is a safe and important adjunct to surgical management of pancreatic pseudocysts. We strongly believe, however, that the interval from ERCP to surgery should not exceed 24 hours.

Cystoduodenostomy for internal drainage of pancreatic pseudocysts has been both condemned and condoned. The current study reports the largest personal experience with a single method of cystoduodenostomy. Transduodenal cystoduodenostomy was performed in 14 cases followed an average of 39 months without mortality, fistula formation, abscess, or hemorrhage. Recurrent pseudocysts developed in two patients, neither in the pancreatic head. In a 15-year combined review of surgical procedures for pancreatic pseudocyst, transduodenal cystoduodenostomy evidenced mortality rates similar to other forms of internal drainage. In direct contrast, laterolateral cystoduodenostomy by suture anastomosis resulted in a 70% mortality rate and should rarely, if ever, be performed.

Thirty-five patients with chronic pancreatitis of varying cause have been treated according to a protocol first introduced in 1979. At the end of a mean follow up time of 2.1 years, only 54% of patients were found to have derived benefit defined by pain relief and improved quality of life. Patients with alcoholic pancreatitis did particularly poorly, and alcoholics who continued to drink almost never benefited. Patients with dilated pancreatic ducts were more likely to do well than those with small ducts, and pancreaticojejunostomy had a satisfactory record of pain relief. Patients with biliary pancreatitis generally did well with cholecystectomy and clearance of the common bile duct. The 40-80% pancreatectomy had a poor record for pain relief, and produced diabetes in the majority of patients in whom it was used. Nothing will reverse the established pathology of chronic pancreatitis, which remains an unsatisfactory condition to treat.