A pancreatic cyst is a fluid-filled sac on or within the pancreas, an organ behind the stomach that produces digestive enzymes and hormones like insulin. These cysts are common, found in 2% to 15% of individuals through imaging studies, and potentially as high as 50% in autopsy series. While many are harmless, some types of pancreatic cysts carry a potential risk of becoming cancerous.
Types of Pancreatic Cysts
Pancreatic cysts are categorized into two main groups: non-neoplastic and neoplastic. Non-neoplastic cysts, like pseudocysts and serous cystadenomas, are generally benign and do not typically become cancerous. Pseudocysts are fluid collections that usually develop following pancreatitis or abdominal injury. Serous cystadenomas are also benign but can grow large enough to cause symptoms, sometimes requiring surgical removal.
Neoplastic cysts, however, have the potential to become cancerous. These include intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs). IPMNs are the most common neoplastic cyst, growing on the pancreatic duct and containing pancreatic juices and mucin. MCNs are less common, primarily affecting women over 50 and typically growing on the body of the pancreas. Solid pseudopapillary neoplasms are rarer, with both solid and liquid components, often found in younger females.
Recognizing Pancreatic Cysts
Many pancreatic cysts do not cause symptoms and are discovered incidentally during imaging tests, such as CT scans or MRIs, performed for other medical reasons. Increased use and improved resolution of abdominal imaging technologies have contributed to a rise in their detection.
When symptoms occur, they are often non-specific and can include persistent abdominal pain that may spread to the back. Other symptoms include nausea, vomiting, unexplained weight loss, feeling full quickly after eating, or jaundice (yellowing of the skin or eyes). These symptoms typically arise if a cyst grows large enough to press on surrounding organs, such as the pancreatic duct, bile ducts, or parts of the gastrointestinal tract.
Diagnosing Pancreatic Cysts
Once a pancreatic cyst is suspected, medical professionals use various imaging techniques to characterize it. Computerized tomography (CT) scans provide detailed information about the cyst’s size and structure. Magnetic Resonance Imaging (MRI) and Magnetic Resonance Cholangiopancreatography (MRCP) are often preferred for highlighting subtle details, including internal components that might suggest a higher cancer risk. MRCP is particularly useful for evaluating cysts within the pancreatic duct.
Endoscopic ultrasound (EUS) offers high-resolution images of the cyst’s morphology and allows for guided fine needle aspiration (FNA). During FNA, fluid is collected from the cyst for laboratory analysis. This fluid can be tested for cytology (presence of cancer cells), amylase levels, and tumor markers like carcinoembryonic antigen (CEA), which helps differentiate between mucinous and non-mucinous cysts and assess their malignant potential. EUS with FNA can significantly improve diagnostic accuracy compared to imaging alone, especially for distinguishing neoplastic from non-neoplastic cysts.
Managing Pancreatic Cysts
The approach to managing a pancreatic cyst largely depends on its type, size, and features, particularly its potential for malignancy. For many benign or low-risk cysts, watchful waiting or surveillance is often recommended. This involves periodic imaging, typically with MRI, to monitor the cyst for changes in size or appearance that might indicate an increased risk. The frequency of surveillance imaging can range from every 3 months to 2 years, depending on cyst characteristics and established guidelines.
Surgical removal is generally recommended for cysts with higher malignant potential, those growing rapidly, or those causing bothersome symptoms like pain or obstruction. This includes certain types of IPMNs, MCNs, and solid pseudopapillary neoplasms. The goal of surgery is to prevent cancer development or alleviate symptoms caused by the cyst. While surgery carries risks, outcomes for surgically resected cysts are generally better than for solid pancreatic tumors.