Cystic Tumors of the Pancreas
Cystic tumors of the pancreas derive their name from the presence of fluid in the tumor. The fluid is produced by the lining of the tumor that is abnormal and may give rise to a cancer in some patients. Cystic tumors of the pancreas are uncommon, and constitute about 2% of all pancreatic tumors. Appropriate diagnosis of these tumors is important since surgical removal of the tumor is associated with a high cure rate.Unresected (surgically not removed) tumors particularly of the mucinous cystadenoma type can lead to invasive pancreatic cancer, a potentially fatal disorder. An important consideration is the separation of these tumors from a condition called pancreatic pseudocyst since cystic tumors are often misdiagnosed as pancreatic pseudocyst and inappropriately treated. Cystic tumor of the pancreas include the following group of tumors:
I. Mucinous Cystadenoma
- Mucinous Cystadenoma
- Serous Cystadenoma
- Mucinous Ductal Ectasia
Mucinous cystadenomas are the most frequent cystic tumors of the pancreas and comprise approximately 50% of all cystic tumors. While these tumors are usually benign, the majority if left untreated will probably evolve to a malignant tumor. 80% of mucinous cystic tumors occur in females and the majority of the tumors occur in the younger female patient with a median age of 54 years.
The radiological (CT x-ray) image of the tumor is characteristic and the diagnosis is made based on this appearance. The treatment of choice is surgical removal of the tumor since if left untreated almost all of these tumors may progress towards the development of invasive pancreatic cancer.
The surgical procedure depends on the location of the tumor. The vast majority of these tumors are precancerous. Because it is a precancerous tumor, it is preferable to avoid radical surgery, we have therefore emphasized techniques of organ preservation for removal of these tumors. For very small tumors in the head of the pancreas we would consider a pancreatic head resection preserving the duodenum and the bile duct.
A Whipple operation is only occasionally indicated for tumors in the head of the pancreas and a distal pancreatectomy is performed for the tumors in the tail of the pancreas. We would preserve the spleen in patients that undergo distal pancreatectomy for these tumors. For tumors in the neck of the pancreas we perform a central pancreatectomy to preserve pancreatic tissue. We offer laparoscopic surgical approaches for distal pancreatectomy and central pancreatectomy.
II. Serous Cystadenoma
Serous cystadenoma is also known as a microcystic adenoma and is a second most common cystic tumor of the pancreas. These tumors have a honeycombed appearance on pathology that appearance is also characteristically seen on the CT scan. Diagnosis is made based on a characteristic CT scan for this tumor. These lesions are almost always benign and progression to cancer is unlikely. The preferred treatment for this lesion is observation without surgery unless the patient has clinical symptoms associated with this tumor.
III. Mucinous Ductal Ectasia
Mucinous ductal ectasia is associated with a very characteristic clinical picture. In this tumor the lining of the pancreatic duct becomes malignant and the cancer cells produce large amounts of thick mucous. The mucous often blocks the pancreatic duct causing recurrent attacks of pancreatitis. This tumor occurs predominantly in the older men with a median age of 66 years. A history of heavy smoking is frequent.
The diagnosis is made during ERCP that shows a markedly enlarged opening of the pancreatic duct into the ampulla vater with mucous extruding from the ampulla. Mucinous ductal ectasia most frequently affects the head of the pancreas, however, the involvement of the lining of the pancreatic duct can be variable from a small amount to extensive involvement requiring removal of most of the pancreas.
The treatment of choice is removal of the tumor at surgery. These tumors are very slow growing and therefore conservative treatment of these tumors without surgery has been advocated. A risk of doing this is possible future development of invasive pancreatic cancer, we therefore would recommend surgery if the patient is otherwise in excellent health.
At the time of the surgery it is important to ensure that the surgical margin is free of disease since the extent of involvement of the pancreas is very variable. We usually also inspect the pancreatic duct at surgery through a tiny scope introduced into the duct to ensure that the remaining duct is free of disease.