Cystic Tumours of Pancreas

What is the epidemiology of pancreatic cystic neoplasm?

Pancreatic cystic neoplasms are being increasingly identified with high-quality abdominal imaging and comprise at least 15% of all pancreatic cystic masses

What are the common types of cystic pancreatic neoplasm?

The three most common primary pancreatic cystic neoplasms are;

Serous cystic neoplasm Mucinous cystic neoplasm Intraductal papillary mucinous neoplasm (IPMN)
Predominantly affect women Women>men Men>women
30% of primary cystic neoplasms 40% 30%
Mostly found in the head of pancreas Mostly in the body and tail Can arise from the main duct or branch duct or both
Well demarcated spongy, honeycomb mass with small cysts Larger often solitary cyst to begin with and may have a septum or septae contained within the cyst. Does not communicate with the pancreatic duct Characterised by intraductal proliferation of neoplastic mucinous cells forming papillae & excess mucous secretion. These changes lead to dilatation of the main pancreatic duct or branch duct.
Fluid analysis- very low CEA and low amylase High CEA (because CEA is being secreted by the columnar and the mucinous epithelium) and low amylase. Cytology will be positive, if malignant transformation
Relatively benign lesion (think of it like hyperplastic polyp of colon) Benign lesion (think of it like adenomatous polyp of colon) but can turn into malignancy. Greatly increased risk of colorectal cancer and other extrapancreatic cancers in patients with IPMN.
May cause local effects, but no systemic problem Local effects only. Malignant transformation can occur. All malignant cystic malignancies come from a mucinous lesion.

What are the clinical features of these cystic neoplasms?

  • 50% of patients do not have any symptoms and are detected incidentally at imaging studies performed for unrelated indications.
  • Symptoms due to mass effect- abdominal pain or mass
  • Patients with malignant change may have weight loss or jaundice
  • Pancreatitis and jaundice secondary to ductal obstruction by mucus plugs are common in IPMTs of the pancreas. Patients may have a history of recurrent acute pancreatitis.

How do you diagnose cystic neoplasms of pancreas?

  • Imaging CT/MR/EUS.
  • If imaging is non diagnostic- use cytology. It could be malignant or nondiagnostic.
  • If cytology is nondiagnostic- use cyst fluid CEA.
    • CEA <5- Benign/serous,
    • CEA 5-200- inflammatory (pseudocyst),
    • CEA>200- mucinous/IPMT,
    • CEA >1000 – malignant.

These values have not been firmly established. However a CEA of < 5- very high likelihood of it being serous and a CEA >200- very high suspicion of mucinous

Discuss the management options?

  • Serous cystadenomas are nearly always benign and may be managed conservatively and kept under radiological surveillance. So, if a lesion can be positively identified as a serous cystic neoplasm then a conservative approach with regular follow-up imaging is justified.
  • Mucinous cystic neoplasms should be resected if the patient is fit for major surgery owing to the high malignant potential.
  • All main duct IPMNs should be resected if the patient is fit, combined with frozen section assessment of the main pancreatic duct resection margin; the patient should be prepared to undergo a total pancreatectomy.
  • Side branch IPMNs that lack malignant features may also be managed conservatively with radiological monitoring.

Ref

  1. British Society of Gastroenterology Guidelines for the Management of Patients with Pancreatic Cancer, Periampullary and Ampullary carcinomas.
  2. Ghaneh P et al. Biology and management of pancreatic cancer. Gut. 2007; 56(8):1134-52

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