Pancreatic cysts are fluid-filled sacs that form within or on the surface of the pancreas. Most are benign and often discovered incidentally during imaging for unrelated conditions. However, some types carry a risk of becoming cancerous and may require monitoring or treatment.
Types of pancreatic cysts
Intraductal papillary mucinous neoplasms (IPMNs) — these are the most common pancreatic cysts and arise from the cells lining the pancreatic ducts. IPMNs produce mucin and often communicate with the pancreatic duct. While many are small and slow-growing, some subtypes, especially those involving the main duct, carry a risk of progressing to pancreatic cancer.
Mucinous cystic neoplasms (MCNs) — typically found in women and located in the body or tail of the pancreas, MCNs are larger cysts that do not connect with the pancreatic duct. They are defined by the presence of a distinctive ovarian-like stroma and carry a moderate risk of malignancy.
Serous cystadenomas (SCNs) — these are usually benign cysts composed of numerous small, fluid-filled sacs. They are more common in older women and rarely become cancerous. SCNs can be further classified into microcystic and macrocystic subtypes.
Solid pseudopapillary neoplasms (SPNs) — rare and most often seen in young women, SPNs contain both solid and cystic components. They are considered low-grade malignant tumours and are typically treated with surgery due to their potential to grow and spread.
Cystic pancreatic neuroendocrine tumours (cystic PanNETs) — these are rare tumours that may develop cystic areas and can be functional (hormone-producing) or non-functional. Some carry a risk of malignancy and may be associated with genetic conditions like MEN1.
Simple cysts and lymphoepithelial cysts — these uncommon, benign cysts do not produce mucin and have no risk of turning cancerous. Lymphoepithelial cysts are characterised by the presence of squamous cells and lymphoid tissue.
Mucinous non-neoplastic cysts — these are benign cysts that produce mucin but have no malignant potential. They are usually managed conservatively.
Pancreatic cysts are fluid-filled sacs that form within or on the pancreas and can range from harmless to potentially cancerous, depending on their type.
What causes pancreatic cysts?
Most pancreatic cysts are idiopathic, meaning their precise origin is unclear, but they are thought to arise from a combination of genetic predisposition, inflammation, tissue injury, or age-related changes
Inherited conditions linked to pancreatic cysts — certain genetic disorders increase the likelihood of cyst formation:
Von Hippel–Lindau syndrome — a hereditary condition that causes multiple benign and malignant tumours as well as cysts in organs like the pancreas and kidneys.
Autosomal dominant polycystic kidney disease (ADPKD) — a genetic disorder primarily affecting the kidneys but also associated with cyst development in the pancreas and liver.
Cystic fibrosis — a genetic disease characterised by thick mucus secretions; it frequently leads to cystic and fibrotic changes within the pancreas.
Other contributing factors — pancreatitis, trauma to the pancreas, and advancing age raise the risk of cyst formation, including pseudocysts that arise after episodes of severe inflammation.
A pancreatic pseudocyst is a fluid-filled sac that typically forms after pancreatitis and can cause abdominal pain or pressure on nearby structures.
What are the signs and symptoms of pancreatic cysts?
Pancreatic cysts are typically asymptomatic, hence they are not commonly a cause for a visit to the doctor. Most cases of pancreatic cysts are detected from abdominal imaging tests, such as CT scans or MRI scans, for other purposes. Occasionally, pancreatic cysts can show gastrointestinal symptoms such as:
Abdominal pain
Jaundice
Loss of appetite
Unexplained weight loss
Nausea and vomiting
Bloating and indigestion
Who is at risk of pancreatic cysts in Singapore?
While pancreatic cysts can affect anyone, certain factors may increase the likelihood of developing them. These include:
Genetics — genetically inherited mutations or disorders can lead to an increased likelihood of developing pancreatic cysts.
Family history — a family history of pancreatic cancers or pancreatic cysts may put you at a higher risk of developing pancreatic cysts.
Smoking — smoking has also been identified as an independent risk factor of pancreatic cysts.
How are pancreatic cysts diagnosed?
As mentioned, pancreatic cysts are typically found during an imaging test for other conditions or purposes. Doctors can diagnose a pancreatic cyst using the following tests:
Computed tomography (CT) scan — CT scans are frequently used to evaluate abdominal concerns and often detect pancreatic cysts incidentally. They also play a key role in monitoring cyst size, features, and changes that may suggest a risk of malignancy.
Magnetic resonance imaging (MRI) — like CT scans, MRI scans are commonly used to detect pancreatic cysts and provide detailed images of the pancreas and surrounding structures. They are particularly useful in evaluating the internal characteristics of cysts and their connection to the pancreatic duct.
Endoscopic ultrasound/fine-needle aspiration (EU-FNA) — Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) involves inserting an endoscope equipped with ultrasound to visualise the pancreas. A fine needle is then used to collect fluid or tissue samples from the cyst for laboratory analysis to assess its type and cancer risk.
Laboratory tests — fluid obtained from the cyst is analysed for cancer biomarkers like carcinoembryonic antigen (CEA), along with cytological examination to assess cell type, structure, and any signs of malignancy.
What are the complications of pancreatic cysts?
While many pancreatic cysts are asymptomatic and benign, untreated or high-risk cysts can lead to significant complications. The likelihood and severity of complications depend on the cyst type, size, location, and whether it obstructs nearby structures.
Pancreatic duct obstruction — certain mucin-producing cysts, such as intraductal papillary mucinous neoplasms (IPMNs), can block the pancreatic duct. This may impair the flow of digestive enzymes and lead to inflammation or tissue damage.
Biliary or gastrointestinal obstruction — large cysts located near the bile duct, stomach, or duodenum can cause compression, resulting in symptoms such as jaundice, delayed gastric emptying, or digestive disturbances.
Pancreatitis — obstruction of the pancreatic duct can cause inflammation of the pancreas (pancreatitis). This may present with abdominal pain, nausea, vomiting, and elevated pancreatic enzymes.
Timely evaluation and appropriate monitoring of pancreatic cysts are essential to avoid complications. If you have been diagnosed with a pancreatic cyst, consult a specialist to determine the most suitable course of action based on its features and your individual risk profile.
What are the treatment options for pancreatic cysts in Singapore?
Not all pancreatic cysts require treatment. Management depends on factors such as the type and size of the cyst, its potential for malignancy, the patient’s age and overall health, and the presence of symptoms or complications.
Surveillance — many pancreatic cysts, particularly those without high-risk features, are monitored over time with regular imaging. MRI or MRCP scans are commonly used to assess changes in size or structure. For stable cysts under 3 cm, annual imaging may be advised for several years before surveillance is tapered or stopped.
Drainage — if a cyst causes symptoms such as pain, infection, or pancreatic duct obstruction, drainage may be required. This can be done endoscopically using endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) or percutaneously through the skin.
Surgical removal — surgery is recommended for cysts with suspicious features or known malignant potential, such as main-duct IPMNs or mucinous cystic neoplasms larger than 3 cm. It may also be considered if the cyst has a solid component, causes main duct dilation, or shows other concerning changes on imaging.
Summary
Pancreatic cysts are fluid-filled growths within the pancreas that range from harmless to potentially cancerous. While many cysts are found incidentally and may not require treatment, others, such as mucinous cystic neoplasms or main-duct IPMNs, can pose a risk of malignant transformation.
Diagnosis typically involves imaging scans, fluid analysis, and sometimes biopsy. Treatment options depend on the type, size, and features of the cyst and may include regular monitoring, drainage, or surgical removal. If left unmanaged, certain cysts can lead to complications such as pancreatitis, duct obstruction, or even pancreatic cancer.
If you have been diagnosed with a pancreatic cyst or are experiencing unexplained abdominal symptoms, schedule a consultation with Tan Siong San Surgery for expert evaluation and personalised care.
Frequently Asked Questions (FAQs)
No, most pancreatic cysts are benign. However, some types, such as mucinous cystic neoplasms and main-duct IPMNs, carry a risk of turning cancerous.
They are often discovered incidentally during imaging scans, such as CT or MRI, performed for unrelated abdominal issues.
Most cysts are asymptomatic, but larger or high-risk cysts may cause pain, nausea, jaundice, or digestive problems due to obstruction.
Some simple or post-inflammatory cysts may resolve, but most pancreatic cysts require monitoring to assess for changes or complications.
Surveillance intervals depend on the cyst’s type and size, typically every 6 to 12 months for several years using MRI or MRCP.
Surgery is considered when a cyst shows high-risk features, causes symptoms, or has malignant potential.
Pseudocysts are non-cancerous fluid collections, usually from pancreatitis, while neoplastic cysts may have precancerous or cancerous potential.
Cysts removed surgically usually do not recur, but new cysts may form, especially in individuals with underlying risk factors.
If the cyst is low-risk and asymptomatic, regular monitoring may be safe. However, evaluation by a specialist is essential to guide this decision.
Discuss your diagnosis with a specialist to determine the cyst type, associated risks, and whether treatment or surveillance is appropriate.
This article has been medically reviewed by Dr. Tan Siong San
Dr Tan is a Senior Consultant Surgeon with over 25 years of clinical experience in the field of Hepato-Pancreato-Biliary (HPB) surgery treating conditions affecting gallbladder, liver and pancreas.
