Tumours and Cysts of Pancreas

The pancreas can develop various types of growths, broadly classified as tumours and cysts. While some are benign (non-cancerous), others have the potential to become malignant (cancerous). Understanding the type and nature of these growths is essential for appropriate management.

Pancreatic cysts are fluid-filled sacs that form within the pancreas. They are increasingly detected incidentally on imaging studies such as CT scans and MRIs performed for unrelated reasons. Most pancreatic cysts are benign, but some types carry a risk of malignant transformation and require surveillance or surgical removal.

Pancreatic tumours include both benign and malignant neoplasms. The most common malignant tumour is pancreatic adenocarcinoma, while neuroendocrine tumours (PNETs) arise from the hormone-producing cells of the pancreas.

Pancreatic cysts are classified based on their lining cell type and malignant potential. The most common types include:

Serous Cystadenoma (SCN)

Serous cystadenomas are benign cysts composed of multiple small cysts filled with clear fluid. They are most commonly found in the body or tail of the pancreas and occur more frequently in middle-aged women. These cysts have virtually no malignant potential and are usually managed with observation unless they grow large and cause symptoms.

Mucinous Cystic Neoplasm (MCN)

Mucinous cystic neoplasms contain thick, mucin-filled fluid and have a potential to transform into invasive cancer. They occur almost exclusively in women and are typically located in the body or tail of the pancreas. Due to their malignant potential, surgical removal is recommended for most MCNs, especially those larger than 3 cm or with worrisome features.

Intraductal Papillary Mucinous Neoplasm (IPMN)

IPMNs arise from the pancreatic duct and produce mucin, causing dilation of the duct. They are classified into main duct type, branch duct type, and mixed type based on involvement of the pancreatic duct system. Main duct IPMNs have a higher risk of malignant transformation and are generally treated with surgical resection. Branch duct IPMNs have a lower risk and may be observed in select patients based on size and features. Whipple procedure or distal pancreatectomy may be required depending on the location of the IPMN.

Pancreatic Pseudocyst

Pseudocysts are not true cysts as they lack an epithelial lining. They develop as a complication of acute or chronic pancreatitis, when pancreatic fluid collects and becomes walled off by fibrous tissue. Management includes observation, endoscopic drainage, or surgical drainage depending on size, symptoms, and maturity of the cyst wall.

Solid Pseudopapillary Neoplasm (SPN)

Solid pseudopapillary neoplasms are rare tumours with low malignant potential, occurring predominantly in young women. They are typically large at presentation and have an excellent prognosis after complete surgical resection.

Pancreatic tumours can be classified based on their cell of origin and biological behaviour:

Pancreatic Neuroendocrine Tumours (PNETs)

PNETs arise from the endocrine (hormone-producing) cells of the pancreas. They can be functional (producing hormones that cause clinical syndromes) or non-functional (not producing clinically significant hormones). Functional PNETs include:

• Insulinoma: The most common functional PNET, causing low blood sugar episodes with symptoms such as sweating, palpitations, confusion, and loss of consciousness.
• Glucagonoma: Causes diabetes, weight loss, and a characteristic rash called necrolytic migratory erythema.
• Gastrinoma: Causes severe recurrent peptic ulcers and diarrhoea (Zollinger-Ellison syndrome).
• VIPoma: Causes profuse watery diarrhoea leading to dehydration and electrolyte imbalances.
• Somatostatinoma: A rare tumour causing diabetes, gallstones, and steatorrhoea.

Non-functional PNETs are more common and are usually detected incidentally. They can grow to a large size before causing symptoms due to mass effect. Surgical resection is the treatment of choice for localized PNETs.

Pancreatic Adenocarcinoma

Pancreatic cancer is the most common malignant tumour of the pancreas. It arises from the exocrine cells and is known for its aggressive behaviour and late presentation. Surgical resection offers the best chance of cure, but only a minority of patients are diagnosed at a resectable stage.

Many pancreatic cysts and benign tumours are asymptomatic and discovered incidentally during imaging for other reasons. When symptoms do occur, they depend on the size and location of the lesion:

Functional PNETs present with symptoms related to hormone overproduction, such as hypoglycaemia in insulinomas or severe peptic ulcers in gastrinomas.

The diagnostic approach to pancreatic cysts and tumours involves a combination of imaging studies, laboratory tests, and sometimes tissue sampling:

Cross-sectional Imaging

A high-resolution, thin-cut, triple-phase CT scan is the primary imaging modality for evaluating pancreatic lesions. It provides detailed information about the size, location, and characteristics of the cyst or tumour. MRI with MRCP (magnetic resonance cholangiopancreatography) is particularly useful for evaluating cystic lesions and their connection to the pancreatic duct.

Endoscopic Ultrasound (EUS)

EUS involves passing an ultrasound probe on the tip of an endoscope into the stomach and duodenum to obtain detailed images of the pancreas. It is especially valuable for characterizing small lesions and guiding fine-needle aspiration (FNA) for tissue diagnosis. Cyst fluid can be aspirated and analysed for tumour markers (such as CEA), amylase levels, and cytology.

Laboratory Tests

Blood tests include tumour markers such as CA19-9 (elevated in pancreatic adenocarcinoma). For suspected PNETs, specific hormone levels such as insulin, glucagon, gastrin, and chromogranin A are measured. Genetic testing may be considered in selected cases.

The treatment depends on the type of lesion, its size, location, malignant potential, and the patient's overall health. Options range from observation to surgical resection.

Observation and Surveillance

Benign cysts such as serous cystadenomas and small branch-duct IPMNs without worrisome features can be managed with periodic surveillance using MRI or CT scans. The frequency of follow-up depends on the size and characteristics of the cyst.

Surgical Resection

Surgical removal is indicated for lesions with malignant potential, symptomatic cysts or tumours, and lesions causing complications. The type of surgery depends on the location of the lesion:

• Enucleation: For small, superficial, benign or low-grade tumours such as insulinomas. The tumour is carefully shelled out from the surrounding pancreatic tissue, preserving maximum healthy pancreas.
• Distal pancreatectomy: For lesions located in the body or tail of the pancreas. This may be performed with or without splenectomy, and can be done laparoscopically or robotically.
• Whipple procedure (pancreaticoduodenectomy): For lesions in the head of the pancreas. This complex operation removes the head of the pancreas, duodenum, bile duct, gallbladder, and part of the stomach with reconstruction of the digestive tract.
• Central pancreatectomy: For benign or low-grade lesions in the neck or proximal body of the pancreas. This procedure preserves more pancreatic tissue than a distal pancreatectomy but carries a higher risk of pancreatic leak.

Endoscopic and Percutaneous Drainage

Pancreatic pseudocysts and selected fluid collections can be drained endoscopically or percutaneously. Endoscopic drainage involves creating a communication between the cyst and the stomach or duodenum, allowing the fluid to drain internally. This is less invasive than surgery and is suitable for mature pseudocysts.

Management of Malignant Tumours

For pancreatic cancer, treatment follows a multimodal approach including surgery, chemotherapy, and sometimes radiation therapy. Whipple procedure is performed for head tumours, while distal pancreatectomy is performed for body and tail tumours. Neoadjuvant or adjuvant chemotherapy is often recommended to improve outcomes.

Surgery for pancreatic cysts and tumours requires careful preoperative planning and should be performed by an experienced pancreatic surgeon at a high-volume centre. The choice of surgical approach depends on the location and nature of the lesion.

Minimally Invasive Surgery

Laparoscopic and robotic approaches are increasingly used for pancreatic resections. Laparoscopic distal pancreatectomy is now considered the standard approach for most lesions in the body and tail of the pancreas, offering benefits such as less postoperative pain, shorter hospital stay, and faster recovery. Robotic surgery provides enhanced precision for complex dissections, particularly when preserving the spleen.

Open Surgery

Open surgery may be preferred for large or locally advanced tumours, lesions involving major blood vessels, or when there has been previous abdominal surgery. It provides excellent exposure and allows the surgeon to assess the extent of disease thoroughly.

Pancreatic Enzyme Replacement

After pancreatic resection, some patients may develop exocrine pancreatic insufficiency, leading to difficulty digesting fats and fat-soluble vitamins. Pancreatic enzyme replacement therapy helps manage this condition and maintain adequate nutrition.

Recovery after pancreatic surgery depends on the extent of resection and the surgical approach. For minimally invasive procedures, hospital stay is typically 3–7 days, while open surgery may require 7–14 days. Most patients can resume normal activities within 4–8 weeks.

• Pain is managed with medications, and early walking is encouraged.
• A liquid diet is started and gradually advanced to solid food.
• Drains placed during surgery are monitored and removed when output is low.
• Patients who had a splenectomy require vaccinations against encapsulated bacteria.
• Long-term surveillance imaging is scheduled based on the type and pathology of the lesion.

Pancreatic surgery carries specific risks that should be discussed with your surgeon before the procedure:

• Pancreatic leak (fistula): Leakage of pancreatic fluid from the cut surface of the pancreas. This is the most common complication and occurs in 10–30% of cases. Most leaks resolve with conservative management.
• Bleeding: May occur during or after surgery.
• Infection: Surgical site infection or intra-abdominal abscess.
• Delayed gastric emptying: Difficulty tolerating food after surgery, more common after Whipple procedure.
• Pancreatic insufficiency: Difficulty digesting food due to reduced pancreatic enzyme production.
• New-onset diabetes: May develop after significant pancreatic resection.