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Cystic neoplasms of the pancreas account for about 1% of all pancreatic tumors. Cystic neoplasms of the pancreas may be classified into 3 categories. True neoplastic cysts, the cystadenomas and cystadenocarcinomas arising from the ductal epithelium, account for 90% of cystic pancreatic tumors.¹Intraductal tumors like intraductal pancreatic mucinous neoplasm and intraductal pancreatic endocrine neoplasm (PEN) may demonstrate cystic dilatation of the distal pancreatic ducts. Solid tumors of the pancreas like ductal adenocarcinoma, acinar cell carcinoma, and PEN may very rarely undergo cystic degeneration following central necrosis.²Truly cystic PEN, however, has also been reported.³

Pancreatic endocrine neoplasms account for less than 5% of all cystic pancreatic neoplasms.³The majority of cystic PENs are nonfunctional.⁴They generally reach a larger size than their solid counterparts.⁵They most commonly occur in the body and tail of the pancreas in patients between the ages of 50 and 60 years.³They are equally distributed between men and women.

One of the most controversial aspects of PENs is the prediction of biologic behavior. Factors that adversely correlate with clinical outcome include tumor size (>3 cm), capsular and vascular invasion, and a mitotic rate greater than 2 of 10 per high-power field. Both in cytology and on tissue sections, immunohistochemical analysis is very helpful in distinguishing endocrine, ductal, and acinar tumors. Most, if not all, PENs show positivity for general endocrine markers, including synaptophysin and chromogranin. The tumor in our patient exhibited all the clinicopathological features of a low-grade, nonfunctioning cystic pancreatic endocrine neoplasm.

About a third of PENs are malignant. Cystic PENs are composed of cystic spaces that may be lined by characteristic islet cells or may contain necrotic material. All PENs should be resected, both to provide relief of symptoms and to detect the presence or absence of malignancy.³

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Correspondence:Adhish Basu, MS, MRCS, Department of General Surgery, Providence Hospital and Medical Centers, 16001 W 9 Mile Rd, Southfield, MI 48075 (adhishbasu@rediffmail.com).

Accepted for Publication:March 11, 2007.

Author Contributions:Study concept and design: Basu and Sistla. Acquisition of data: Basu and Iyengar. Analysis and interpretation of data: Basu. Drafting of the manuscript: Basu. Critical revision of the manuscript for important intellectual content: Sistla and Iyengar. Administrative, technical, and material support: Basu and Iyengar. Study supervision: Sistla and Iyengar.

Financial Disclosure:None reported.