Pancreatic Cysts - Types, Causes, Symptoms, Complications, Treatment & Prevention

Pancreatic cystic lesions are a traditional term that refers to a well-defined lesion or sac-like pockets in the pancreas that contains fluid. 

They are characterised by liquid inside, with an outer skin, and can range in size from just a few millimetres to several centimetres wide. However, the majority are small and less than a centimetre or two in diameter.

Prevalence of pancreatic cyst

The prevalence of pancreatic cysts varies greatly depending on the imaging method used, ranging from 0.21% with ultrasound to 50% in autopsy studies, and it increases with age.

Globally, pancreatic cystic lesions (PCLs) are common, with multiple studies suggesting a prevalence ranging from 2% to 38% depending on the imaging modality used, with an overall prevalence of around 15%.

While data on the prevalence of pancreatic cysts in India is limited, studies suggest a prevalence of around 2.5% in asymptomatic populations, increasing with age. However, some studies show higher rates, particularly in older age groups.

Types of Pancreatic Cysts

Pancreatic cystic lesions can be classified as: 

Benign cysts

non-cancerous, e.g., simple cysts, Pancreatic pseudocysts, and serous cystic neoplasms (SCNs).

Cysts with malignant potential

e.g., mucinous cystic neoplasms (MCNs) and intraductal papillary mucinous neoplasms (IPMNs).

Malignant cysts

Neoplastic cysts such as pancreatic adenocarcinomas with cystic degeneration and cystic pancreatic neuroendocrine tumors.

Pseudocysts: Pseudocysts are the most common type, which emerges following either acute or chronic pancreatitis. They usually manifest as one or more unilocular cysts that may contain debris and cannot become malignant (not able to develop into cancer). Intervention is only necessary for symptomatic pseudocysts; the majority resolve on their own.

Serous cystadenomas: Serous cystadenomas are slow-growing, benign lesions that primarily affect women between the ages of five and seven. Although they might appear as solid, macrocystic, or unilocular lesions, these cysts typically have a microcystic (honeycomb) look. They are incapable of developing into cancer.

Mucinous Cystic Neoplasm: The less prevalent mucinous cysts are called MCNs and are typically seen in the distal pancreas. They are single, thick-walled, primarily unilocular cysts.

They primarily affect women between the ages of 40 and 50 and can develop into cancer. Furthermore, they characteristically contain ovarian-like stroma and almost exclusively affect women in the fourth to sixth decades of life.

Intraductal Papillary Mucinous Neoplasm: IPMNs are the most common type of mucinous cystic lesions. Pancreatitis may coexist with intraductal papillary mucinous neoplasm (IPMNs); men are more likely than women to have this condition. These ductal cell-derived neoplasms are frequently multifocal and spread throughout the pancreas. IPMNs have the potential to become malignant.

Solid Pseudopapillary Neoplasm: The rarest pancreatic cyst is a solid pseudopapillary neoplasm, primarily affecting women in their second or third decade. These well-defined, heterogeneous lesions, which can be found all over the pancreas, contain solid and cystic components and occasionally irregular calcifications. Although most pancreatic cysts are benign, some have the potential to become cancerous.

Revised WHO histological classification of pancreatic cystic neoplasms (WHO pancreatic cyst classification):

• Serous cystic neoplasm (SCN)
• Serous cystadenoma
• Serous microcystic adenoma (Benign)
• Serous oligocystic adenoma (Benign)
• Serous cystadenocarcinoma (Malignant)

• Mucinous cystic neoplasm (MCN)
• Mucinous cystadenoma (Benign)
• Mucinous cystic neoplasm
• Low-grade (Borderline)
• High-grade (Carcinoma in situ)
• Mucinous cystadenocarcinoma
• Non-invasive (Malignant)
• Invasive (Malignant)

• Intraductal papillary mucinous neoplasm (IPMN)
• Intraductal papillary mucinous neoplasm
• Low-grade (Borderline)
• High-grade (Carcinoma in situ)
• Intraductal papillary mucinous carcinoma
• Non-invasive (Malignant)
• Invasive (Malignant)

• Solid pseudopapillary neoplasm
• Solid pseudopapillary neoplasm (Borderline)
• Solid pseudopapillary carcinoma (Malignant)

Pancreatic Cyst Symptoms

Most pancreatic cysts are not symptomatic (asymptomatic) and are discovered incidentally on diagnostic imaging that is carried out for an unrelated symptom or reason. The following are the common signs and symptoms of pancreatic cysts that can be seen in some patients, including:

• Jaundice: It is a rare symptom in patients with pancreatic cysts (less than 1%). However, it is a more common feature if cysts are huge or contain cancer cells. It happens due to a build-up of bilirubin (a chemical constituent of bile) in the blood. Jaundice can occur if a cyst in the pancreatic head compresses or blocks the ducts carrying bile from the liver.
• Abdominal pain: Small cysts, e.g. less than 2cm, usually do not cause pain. However, as cysts enlarge, they may exert pressure on the surrounding tissues and nerves, leading to persistent back or upper abdominal pain.
• Nausea and vomiting: Compression of the duodenum delays stomach emptying (gastric emptying), resulting in a feeling of fullness, which may lead to nausea and vomiting.
• Weight loss: It is a rare symptom; if the cysts are large, they can decrease the pancreas's ability to produce digestive enzymes, causing poor digestion of food and resulting in weight loss.

Potential symptoms related to specific types of cysts include:

Serous cystic neoplasm (SCN)

• Signs: Palpable mass 
• Symptoms: Mostly asymptomatic 
• If these SCNs are large, they cause gastric outlet obstruction and bile duct obstruction

Solid pseudopapillary neoplasm (SPN)

• Common symptoms: May present with nausea, abdominal pain, vomiting, and weight loss
• Other signs and symptoms: Anaemia, jaundice, gastric outlet or intestinal obstruction and pancreatitis.

Mucinous cystic neoplasm (MCN)

• Symptoms: Most patients are asymptomatic; possible symptoms include back pain, abdominal pain
• Signs: It may present as a palpable mass 
• Other features: Recurrent pancreatitis, gastric outlet obstruction, jaundice, and weight loss are more familiar with malignant lesions.

Intraductal papillary mucinous neoplasm (IPMN)

• Symptoms and signs: Mostly asymptomatic, some patients have symptoms suggestive of chronic pancreatitis, which results from intermittent obstruction of the pancreatic duct with mucus plugs. Manifestations such as back pain, jaundice, weight loss, anorexia, steatorrhea, and diabetes are precursors of malignancy.
• Other features: Some patients have a long-standing history of recurrent acute pancreatitis

Neuroendocrine tumors (NET)

• May rarely manifested as cystic lesions
• Most are asymptomatic, but symptoms or signs due to the production of hormones may be present.

Pancreatic Cyst Causes

The exact reason for most pancreatic cysts is still idiopathic (unknown). However, some cysts might be partly hereditary and partly triggered by other factors, including:

• Genetic Disorders: As mentioned above, hereditary syndromes, including von Hippel-Lindau disease, cystic fibrosis, and polycystic kidney disease, are associated with pancreatic cysts.

• Pancreatitis: Pancreatitis, both acute and chronic, is a leading cause of pancreatic cysts. Inflammation can lead to the leakage of pancreatic enzymes, forming pseudocysts.

• Alcohol use: Over-alcohol consumption is the leading contributor to many health conditions, particularly pancreatitis, raising the risk for pancreatic cysts.

• Advancing age: Pancreatic cysts become more common as you get older. They affect an estimated 25% of people in their 70s.

• Family history: Some persons may be more likely to have pancreatic cysts if they have a family history of pancreatic cancer or if they have a hereditary syndrome associated with cysts.

• High Blood Calcium or Cholesterol Levels: Elevated calcium or fat levels in the blood can harm the pancreas and contribute to cyst formation.

• Infections: Rare infections like tuberculosis or parasitic infections (e.g., tapeworms) can also trigger pancreatic cyst formation.
  

Pancreatic Cyst Risk Factors

Pseudocysts almost always occur following a bout of acute pancreatitis, a painful condition in which digestive enzymes become prematurely active and irritate the pancreas. Common risk factors for pancreatitis include:

• Heavy alcohol use: As mentioned above, heavy consumption of alcohol can increase the risk of pancreatitis, contributing to the significant risk of the formation of cysts in the pancreas.

• Gallstones: Gallstones can increase the risk of pancreatic cysts, particularly pancreatic pseudocysts, by causing pancreatitis by leaking the digestive enzymes, damaging the tissue, and potentially leading to cyst formation. 

• Age: The risk of developing many pancreatic cysts, e.g. IPMN, increases with age. Some cysts are seen almost exclusively in women, like mucinous cystic neoplasms (more than 90%) and serous cystadenoma (more than 70%).

Pancreatic Cyst Complications

Complications are not common with pancreatic cysts, though they may include:

• Pancreatic cancer: Less than 1% of cysts can turn into cancer, most commonly adenocarcinoma, having the capability to spread. Hence, early detection is vital.

• Bile duct obstruction: A large cyst can obstruct the bile duct, causing jaundice (yellowing of the skin and eyes) and other biliary complications. 

• Pancreatic Duct Obstruction: Certain mucinous cysts can obstruct the pancreatic duct, leading to problems with pancreatic function.

• Haemorrhage: Bleeding or cyst haemorrhage may occur within the cyst or surrounding tissues, resulting in internal bleeding and shock.

• Rupture: A ruptured cyst can cause internal bleeding and infection of the abdominal cavity (peritonitis), which can be life-threatening. 

• Gastrointestinal Obstruction: In some cases, huge cysts can compress the intestine or stomach, causing various gastrointestinal issues, including stomach pain and discomfort. These cysts can prevent food from passing through the GI tract in severe cases.

• Pancreatic abscess and sepsis: If the cyst becomes infected, it may lead to pancreatic abscess and sepsis, requiring immediate medical attention.
  

Diagnostic Approach Options

Pancreatic cysts are most commonly discovered during scans conducted for other issues, like checking for kidney stones. However, patients experiencing symptoms such as abdominal pain, weight loss, or nausea and vomiting may undergo tests to identify the cause of these symptoms, which can include:

Blood tests

• Complete blood count
• Liver function tests (LFTs)
• Kidney function test

Imaging studies

• CT
• MRCP
• MRI
• Trans Abdominal Ultrasound:
• Endoscopic ultrasonography (EUS)
• Endoscopic retrograde cholangiopancreatography (ERCP)

Biopsies

• EUS-guided FNA

Cytology, smears

• Cyst fluid analysis
  

Pancreatic Cyst Treatment

Depending on the size, type of cyst, symptoms, and any suspicion of cancer, a healthcare professional may recommend one or several treatments, or a combination of treatments. 

Conservative treatments Pancreatic Cyst

• Medications
• Antibiotics
• Enzyme replacement therapy
• Monitoring & Observation
• Regular Imaging
• Observation
• Drainage Procedures
• Endoscopic Drainage
• Percutaneous Drainage

Surgical Treatments Pancreatic Cyst

• Cyst Resection
• Pancreaticoduodenectomy (Whipple Procedure)
• Other Procedures
• Sclerotherapy
• Ethanol Injection
  

Prevention of Pancreatic Cysts

Certain lifestyle changes and habits can reduce the risk of developing cysts, even though some cannot be avoided.

• Refraining from Drinking Too Much Alcohol: Reducing alcohol consumption can help avoid pancreatitis, which can cause pancreatic cysts.



• Managing gallstones: Gallstones are a significant cause of pancreatitis, and addressing them is vital to prevent future pancreatic cysts.

• Exercising regularly: Regular exercise helps maintain a healthy weight and supports pancreatic function in general.

• Monitoring Blood Sugar Levels: Especially in diabetics, controlling blood sugar can reduce the risk of pancreatic issues, including cysts.

• A nutritious diet: Maintaining pancreatic health and lowering the risk of cyst formation can be achieved by eating a balanced diet rich in fruits, vegetables, and whole grains.

Differences between Pancreatic Cyst and Pseudocyst