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.
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