Pancreatic cysts are fluid-filled ‘pockets’ or sacs found within the pancreas gland. They are commonly found ‘incidentally’ on CT and MRI scans of the abdomen performed for other reasons. Some studies have reported the prevalence of pancreatic cysts to be up to 10%.
The main concern with pancreatic cysts is the risk of them turning cancerous (malignant). There are several different types of pancreatic cysts each with a different risk profile. In general, the most common types of cysts are considered benign and have a very low risk of cancer.
There are however some cysts that have a higher risk of cancer and should be watched closely or removed with surgery.
Most pancreatic cysts do not cause any symptoms. They are usually found while having a CT or MRI scan for another reason.
If a cyst is in a delicate location or grows to a large enough in size, it can cause stomach discomfort, nausea and a feeling of fullness. Occasionally a cyst can also block the drainage of the pancreas and cause ‘pancreatitis’.
While identifying the presence of a cyst on CT or MRI is straightforward, determining the exact subtype of the cyst can be very difficult. This is because the pancreas gland is deep within the abdomen and hard to access. Cysts can also look very similar to one another and have a very thin wall, which makes collecting cells quite challenging.
Different types of cysts that can be found in the pancreas are: serous cyst adenoma (SCA), mucinous cystic neoplasm (MCN), intraductal papillary mucinous neoplasm (IPMN), and cystic neuroendocrine tumour. There is also an entity called a pseudocyst that occurs affect a severe bout of pancreatitis.
Endoscopic ultrasound (EUS) is the best method for assessing the structure of a cyst, as well as for taking a sample of the cyst fluid or cyst wall. An endoscopic ultrasound is a painless procedure during which a thin flexible tube (with a tiny ultrasound probe on the end) is passed through the mouth into the stomach. The cyst can be aspirated through a technique called fine needle aspiration (FNA) or a biopsy can be taken called a ‘core biopsy’. The fluid and tissue taken during the procedure are analysed in the lab to look for cancer cells and well as to further identify the type of cyst.
Most pancreatic cysts do not require treatment. Depending on the suspected ‘type’ of cyst, many of them need to be ‘watched’. This is to monitor for changes that may be suspicious for the development of pre-cancerous cells.
There are several new techniques currently in development to remove or ablate pancreatic cysts. These include ‘burning’ them with radio-frequency ablation as well as injecting them with chemotherapy drugs. At the moment however these techniques are experimental.
The mainstay of treatment if a cyst does become cancerous is for it to be removed with surgery.