• Patients not progressing to operation due to the development of symptoms, growth to a maximum diameter of >3cm, or development of a mural nodule. [ Time Frame: 3 years ] [ Designated as safety issue: No ]
  

• A decrease in size by >1 cm on MRCP Relative decrease in size of cyst after 1 or 2 injections with ethanol Is reduction in size durable (over what length of time)? [ Time Frame: 3 years ] [ Designated as safety issue: No ]
  

The appropriate management of patients with cystic lesions of the pancreas is controversial. The identification of small asymptomatic pancreatic cysts is increasing due to an improvement in the quality of radiologic imaging and the frequency that imaging is obtained. However, the natural history of these lesions is unknown1. The current consensus guidelines established at the International Consensus Conference in Sendai, Japan in 2005 suggest that branch chain IPMNs and mucinous cystic neoplasms that cause no symptoms, measure <3cm, and have no nodules can be observed with periodic imaging.

However, the time course of these pre malignant mucinous lesions, intraductal papillary mucinous neoplasms (IPMN) or mucinous cystadenomas, from benign to malignant has not been determined. Due to the unknown natural history, and diagnostic uncertainty, some authors have recommended routine resection2, 3. Resection, despite improvements in surgical outcomes after pancreatectomy at high volume centers, carries a mortality and morbidity of 1-6% and 35-51%, respectively4-6. More recently studies are reporting a more selective approach to avoid the risk of operation in patients with benign lesions7.

Improved radiographic and endoscopic studies have been able to identify some lesions with increased malignant potential8, 9. Thus, most patients will undergo pancreas specific radiologic imaging and endoscopic ultrasound with cyst aspiration. Since the natural history of cystic lesions is poorly understood no clear guidelines for surgical resection have been established. Some of the cysts will grow over time, with an increase in the cumulative risk of malignancy. Therefore, the therapeutic alternatives are to wait and watch for a change in the cyst morphology or to treat preemptively, which has been restricted to surgical resection. Based on the pilot study performed by Dr. William Brugge, at Massachusetts General Hospital, ethanol lavage of pancreatic cysts is safe and will result in a decrease in cyst diameter in 61% of patients. Additionally, if patients elect to not be treated preemptively it is unclear how to best follow these patients in terms of the type and the frequency of follow up studies.