According to the Atlanta Symposium, a fluid collection more than 4 weeks old and surrounded by a wall is defined as a pancreatic pseudocyst . In acute pancreatitis, necrosis of peripancreatic tissue or parenchyma can cause liquefaction and subsequent organization resulting in pseudocysts. In chronic pancreatitis, an acute exacerbation of pancreatitis or progressive ductal obstruction can cause pseudocyst formation. Also a blunt or penetrating trauma and injury during pancreatic surgeries can disrupt the pancreatic duct causing pseudocyst formation. These cysts can present with a wide range of clinical manifestations such as abdominal pain, duodenal or biliary obstruction, vascular occlusion, fistula formation into pleural space or pericardial space and digestion of an adjacent vessel resulting in pseudoaneurysms. The diagnosis of pancreatic pseudocysts is made using imaging techniques in the appropriate clinical context.
Giant acute pseudo-pancreatic cyst can occur after acute pancreatitis and they measure 10 cm or more in major diameter. Several giant cysts have been reported in literature. Bozeman in 1882 reported the largest pancreatic pseudocyst cyst, which weighed 10 kg . Other reported cases are a giant pseudocyst containing about 6100 mL of fluid , one measuring 25 × 17 cm, containing 4.5 L of fluid , 25.7 cm × 15.3 cm × 10.9 cm sized one containing 3 L of , one with a diameter of 21 cm  and another one with diameter of 22 cm . The pseudocyst we describe here is much larger than these pseudocysts and its largest locule measured 30 cm × 15 cm × 14 cm in size.
In one study of 74 patients with pseudocysts following acute pancreatitis, those with a high Ranson score were at a significant risk for developing giant pseudocysts and worse outcome . Our patient did not have any organ failure during the first episode of acute pancreatitis but the 48-h CRP was high. We were unable to calculate Ranson score.
The management of pseudocysts is based on the studies done in the past that showed pseudocysts persisting beyond 6 weeks rarely resolve and develop complications nearly in about 50% during continued observation. Bradley EL and colleagues concluded that prolonged observation of pancreatic pseudocysts beyond 7 weeks greatly exceeded the mortality of elective surgery . According to Shatney optimal timing of the operation in patients with uncomplicated pseudocysts appears to be around 4 weeks . Vitas suggested a more conservative approach concluding that nonoperative, noninterventional, expectant approach is warranted in the management of selected patients with pancreatic pseudocysts . In 1990 Yeo and colleagues followed up 75 patients with pancreatic pseudocysts and showed that a large proportion of patients with pancreatic pseudocysts, without specific indications for operative treatment, can be safely managed non-operatively with careful clinical and roentgenographic follow-up study . In this study Pseudocysts greater than 6 cm in diameter required surgical treatment significantly more frequently compared to pseudocysts of less than 6 cm in diameter . The patient in our case required interventions due to the pseudocyst being large and symptomatic.
Radiologic imaging with percutaneous catheter drainage and endoscopic drainage are now two additional treatment options. Surgical drainage was the only form of therapy in the past comprising of internal drainage (in the form of a cystogastrostomy, cystoduodenostomy  or a Roux-en-Y- cystojejunostomy), external drainage or excision of the cyst. In a recent randomized trial in 2013, comparing efficacy of endoscopic and surgical cystogastrostomy for pancreatic pseudocyst drainage, both methods were to be of similar efficacy. However, endoscopic treatment was associated with shorter hospital stays and better physical and mental health of patients with a lower cost . In another two studies endoscopic drainage of pancreatic-fluid collections was successful in the majority of patients and was highly effective [18, 19]. The addition of endoscopic ultrasonography for endoscopic drainage is a new development making it minimally invasive, effective and a safe approach with reduce risk associated with endoscopic drainage [20, 21]. A study that compared endoscopic and percutaneous drainage of symptomatic pancreatic fluid collections concluded that endoscopic drainage was associated with higher rates of treatment success, lower rates of re-intervention and shorter lengths of hospital stay .
There are only few case studies in literature regarding the management of giant pseudo cysts. Behrman and colleagues concluded that expectant management of giant pseudo cysts was associated with higher morbidity and mortality than with small pseudo cysts. They suggested that earlier external drainage, before clinical deterioration, may be beneficial in giant pseudocysts . Wang and colleagues performed an open cystogastrostomy on a 65-year-old man with a giant pancreatic pseudocyst and he recovered uneventfully . Johnson and colleagues reported four patients with giant pseudocysts treated by cystogastrostomy who developed postoperative complications as a result of incomplete emptying of the cyst. From this study they concluded that cystogastrostomy might not be appropriate for the treatment of giant pancreatic pseudocysts as it failed to provide dependent drainage of a large cysts in these patients. It was also concluded that if internal drainage was performed, the cyst should be anastomosed to a defunctional loop of jejunum in a dependent position. They also stated that in some instances external drainage of giant pancreatic pseudocysts may be safer than cystogastrostomy . Ten patients with acute giant pseudocysts underwent video-assisted pancreatic necrosectomy at the time of internal drainage and this was shown to prevent postoperative retroperitoneal complications. This study illustrated that depending on appropriate surgical timing, video-assisted necrosectomy is a feasible and safer procedure when managing giant pseudocysts . Laparoscopic cystogastrostomy was successfully done on a 60-year-old lady with a giant pseudocyst of the pancreas with a good outcome . Here we performed endoscopic ultrasonography and inserted two stents and pigtails to drain the cyst. Later the two stents were removed leaving the pigtails in situ. Patient’s symptoms improved with the drainage of pseudocyst and did not required open surgery. However three repeated endoscopy procedures had to be performed and had a prolong hospital stay of 3 weeks.
With our experience we suggest endoscopic guided internal drainage as a possible initial method of management of giant pseudo cysts. However, long-term follow up is needed to make sure that it does not recur and multiple repeated endoscopy might be needed. In instances, in which the primary endoscopic internal drainage fails, surgical procedures may be required as a second line option.
In conclusion, giant pancreatic pseudocysts are rare and only few case reports are available on its management. Earlier surgical drainage was the only option for pseudocysts but lately radiologic imaging with percutaneous catheter drainage and endoscopic drainage have become available. Earlier drainage was suggested for giant pseudocysts before clinical deterioration. Some suggest that cystogastrostomy may not be appropriate for the treatment of giant pancreatic pseudocysts and in some instances external drainage of giant pancreatic pseudocysts may be safer than cystogastrostomy. Video-assisted pancreatic necrosectomy with internal drainage and laparoscopic cystogastrostomy were also tried with good outcomes. Here we describe a patient with giant pseudocyst following acute pancreatitis who underwent endoscopic ultrasonography and internal drainage of the cyst using stents and pigtails successfully. This can be used as a primary treatment method for giant pseudo cysts although long term follow up with imaging is necessary.