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Pancreatic Pseudocyst, Pediatric

Basics

- Walled-off necrosis (WON) - Collection of varying amounts of liquid and solid material surrounded by a mature, enhancing wall of reactive tissue - Represents a mature, encapsulated ANC - Develops no earlier than 4 weeks after episode of necrotizing pancreatitis - May be multiple and present at sites distant from the pancreas - May be sterile or infected

- Abdominal tenderness - Abdominal mass - Nausea and vomiting - Weight loss - Jaundice - Abdominal distention - In many situations, no clinical signs are seen. - Clinical signs may be secondary to complications: - Jaundice in hepatobiliary obstruction - Lower limb edema in compression of inferior vena cava - Ascites in peritonitis - Pleural effusion

- Congenital/genetic - Congenital cysts - Polycystic disease - Von Hippel-Lindau disease - Cystic fibrosis

- Infections - Pancreatic abscess - Echinococcal (hydatid) cyst - Taenia solium cyst

- Drainage - Most often used in the setting of WON - Indications: infection, rupture with cardiopulmonary compromise, biliary and gastric outlet obstruction, persistent symptoms, rapid enlargement, failure of large pseudocysts (>6 cm) to shrink after 6 weeks - Modalities: - Percutaneous drainage (aspiration or catheter drainage) is done in cases in which the pseudocyst has a less mature wall. - Percutaneous aspiration has a high recurrence rate of 63% and failure rate of 54%. - Continuous drainage has a recurrence rate of 8% and a failure rate of 19%. - Endoscopic procedures are becoming the 1st-line drainage modality, as they are less invasive than surgery. - Endoscopic procedures include transmural cystoenterostomies and transpapillary route procedures such as stent placement for pseudocysts that communicate with the main pancreatic duct. - Endoscopic procedures in experienced hands report success rates of 82 " 89%, complication rates of 10 " 20%, and recurrence rates of 6 " 18%.

- Hemorrhage - Erosions of vessels lining the cyst cause intracystic bleeding and rapid increase in the cyst size. - Bleeding may occur directly into stomach, duodenum (clinically manifesting as GI bleeding), or peritoneal cavity.

- Obstruction - Biliary obstruction: jaundice - Portal obstruction: portal hypertension - Gastric outlet obstruction - Inferior vena cava obstruction: peripheral edema - Urinary obstruction - Colonic obstruction

  • A pancreatic pseudocyst is a peripancreatic (or intrapancreatic) fluid collection associated with a history of pancreatitis, that is surrounded by a well-defined inflammatory wall, and that has no solid component.The term "pseudocyst " is often incorrectly used to define various types of fluid collections associated with pancreatitis. As a result, medical literature on pseudocysts is not consistent in its descriptions or its findings.An important distinction between "fluid collections " associated with pancreatitis is that some consist of fluid alone, whereas others arise from necrosis of pancreatic parenchyma and/or peripancreatic tissues. The latter type of fluid collection involves a solid component (with variable amounts of fluid), which distinguishes them from pseudocysts.
  • Types of fluid collections:Acute peripancreatic fluid collection (APFC)A fluid collection that develops in the early phase of interstitial edematous acute (typically mild) pancreatitisLack a well-defined wall on CT scanNOT associated with necrotizing pancreatitisRemain sterile, and usually resolve without interventionIf APFC persists beyond 4 weeks, likely to develop into a pancreatic pseudocyst; although this is considered a rare outcome.Pancreatic pseudocystRefers specifically to a peripancreatic (or less commonly, an intrapancreatic) fluid collectionSurrounded by a well-defined inflammatory wall and containing NO solid materialPancreatic pseudocysts develop more than 4 weeks after the onset of interstitial pancreatitis.Acute necrotic collection (ANC)A collection of BOTH variable amounts of fluid and solid (necrotic) material related to pancreatic and/or peripancreatic necrosisOccur within the first 4 weeks of disease, and can resemble an APFC in the first few days of acute pancreatitisAs necrotizing pancreatitis develops and necrosis evolves, solid component become evident.May be multiple and may involve the pancreatic parenchyma alone, the peripancreatic tissue alone, or most commonly bothMay be infected or sterileGenerally associated with more severe sequelae of APWalled-off necrosis (WON)Collection of varying amounts of liquid and solid material surrounded by a mature, enhancing wall of reactive tissueRepresents a mature, encapsulated ANCDevelops no earlier than 4 weeks after episode of necrotizing pancreatitisMay be multiple and present at sites distant from the pancreasMay be sterile or infected

Pathophysiology

  • Pseudocysts occur when there is disruption in the pancreatic ductular system, or its intrapancreatic branches, without any evidence of pancreatic or peripancreatic necrosis.
  • This results in the extravasation of pancreatic enzymes evoking an inflammatory response.
  • The inflammatory reaction leads to a fluid collection that is rich in pancreatic enzymes (APFC).
  • If the duration of the fluid collection is >4 weeks, becomes localized (intrapancreatic or extrapancreatic), and develops a fibrin capsule, it becomes a pseudocyst.
  • A pseudocyst does not have a true epithelial lining.
  • If there is communication between the pseudocyst and the pancreatic duct, the enzyme level in the fluid remain elevated; if there is no communication, the enzyme level falls with time.

Diagnosis

History

Acute or chronic pancreatitis

  • Suspect pancreatic pseudocyst in patients recovering from acute pancreatitis, or in the patient with chronic pancreatitis, who has recurrent/persistent abdominal pain, a palpable abdominal mass, or persistently elevated serum pancreatic enzymes.

Physical Exam

  • Abdominal tenderness
  • Abdominal mass
  • Nausea and vomiting
  • Weight loss
  • Jaundice
  • Abdominal distention
  • In many situations, no clinical signs are seen.
  • Clinical signs may be secondary to complications:Jaundice in hepatobiliary obstructionLower limb edema in compression of inferior vena cavaAscites in peritonitisPleural effusion

Diagnostic Tests & Interpretation

Lab

Serum pancreatic enzyme levels:

  • Persistently elevated enzymes in blood can be a clue, but is not an absolute indicator.
  • Elevated enzymes in fluid drained from a peripancreatic or intrapancreatic fluid collection with no solid component is consistent with a pancreatic pseudocyst.

Imaging

  • CT scanReveals pseudopancreatic cyst; can also be used to gauge size of pseudocyst and its relationship to adjacent organs
  • UltrasonographyVisualizes pancreatic pseudocystsCan be used to follow cyst size over time
  • Endoscopic ultrasonography (EUS)Common modality in adult patients and increasingly used in pediatricsCan be used to diagnose presence and size of pseudocyst; can also be used to guide peroral fluid aspiration and drainage
  • Endoscopic retrograde cholangiopancreatography (ERCP)Used in some cases to delineate the pancreatic ductular system before drainage to distinguish ductal stenosis, disruption, stones, and other obstructions

Differential Diagnosis

  • Congenital/geneticCongenital cystsPolycystic diseaseVon Hippel-Lindau diseaseCystic fibrosis
  • InfectionsPancreatic abscessEchinococcal (hydatid) cystTaenia solium cyst
  • TumorSerous cystadenomaMucinous cystadenomaCystic islet cell tumorsTeratomaPancreatoblastomaCystadenocarcinomaFranz tumorAngiomatous cystic neoplasmsLymphangiomasHemangioendothelioma
  • Miscellaneous:Splenic cystAdrenal cystEnterogenous cystDuplication cystsEndometriosis

Treatment

General Measures

  • Medical management:Most cases resolve with supportive care.If eating precipitates pain, short-term nasojejunal feedings or parenteral nutrition may be warranted.Follow up with ultrasound or CT scan to make sure there are no complications.>60% have complete resolution by the end of 1 year.Usually, no medications are used for managing pseudocysts.Somatostatin analogue (octreotide) has been reported to be used to decrease fluid collection along with drainage.Antibiotics are used in situations of infected pseudocyst.
  • DrainageMost often used in the setting of WONIndications: infection, rupture with cardiopulmonary compromise, biliary and gastric outlet obstruction, persistent symptoms, rapid enlargement, failure of large pseudocysts (>6 cm) to shrink after 6 weeksModalities:Percutaneous drainage (aspiration or catheter drainage) is done in cases in which the pseudocyst has a less mature wall.Percutaneous aspiration has a high recurrence rate of 63% and failure rate of 54%.Continuous drainage has a recurrence rate of 8% and a failure rate of 19%.Endoscopic procedures are becoming the 1st-line drainage modality, as they are less invasive than surgery.Endoscopic procedures include transmural cystoenterostomies and transpapillary route procedures such as stent placement for pseudocysts that communicate with the main pancreatic duct.Endoscopic procedures in experienced hands report success rates of 82 " 89%, complication rates of 10 " 20%, and recurrence rates of 6 " 18%.

Surgery/Other Procedures

  • Reserved for failed endoscopic procedures, difficult to access areas of WON and multiple WONs
  • Includes internal drainage (cystogastrostomy, cystoduodenostomy, and Roux-en-Y cystojejunostomy), resection, and external drainage
  • Success rate is 85 " 90%.
  • Recurrence rate is 0 " 17%.
  • Mortality rate is between 3 and 5%.

Ongoing Care

Prognosis

Majority of pseudocysts resolve without intervention.

Complications

  • Perforation/ruptureCardiopulmonary compromise secondary to pleural effusion and ascitesPeritonitis and ascites, which can be fatal
  • HemorrhageErosions of vessels lining the cyst cause intracystic bleeding and rapid increase in the cyst size.Bleeding may occur directly into stomach, duodenum (clinically manifesting as GI bleeding), or peritoneal cavity.
  • ObstructionBiliary obstruction: jaundicePortal obstruction: portal hypertensionGastric outlet obstructionInferior vena cava obstruction: peripheral edemaUrinary obstructionColonic obstruction
  • Infection of pseudocysts is rare in children compared to adults:Associated with high mortality rate for children and adultsManagement usually requires surgical drainage.

Additional Reading

  • Law NM, Freeman ML. Emergency complications of acute and chronic pancreatitis. Gastroenterol Clin. 2002;32(4):1169 " 1194. [View Abstract]
  • Reber HA. Surgery for acute and chronic pancreatitis. Gastrointest Endosc. 2002;56(6)(Suppl):S246 " S248. [View Abstract]
  • Sarr MG, Banks PA, Bollen TL, et al. The new revised classification of acute pancreatitis 2012. Surg Clin North Am, 2013;93(3):549 " 562. [View Abstract]
  • Vidyarthi G, Steinberg SE. Endoscopic management of pancreatic pseudocysts. Surg Clin North Am. 2001;81(2):405 " 410. [View Abstract]
  • Weckman L, Kylanpaa ML, Poulakkainen P, et al. Endoscopic treatment of pancreatic pseudocysts. Surg Endosc. 2006;20(4):603 " 607. [View Abstract]

Codes

ICD09

  • 577.2 Cyst and pseudocyst of pancreas

ICD10

  • K86.3 Pseudocyst of pancreas

SNOMED

  • 111374002 pseudocyst of pancreas (disorder)
  • 405563007 Infected pancreatic pseudocyst (disorder)