Operative indications for cystic lesions of the pancreas with malignant potential - Our experience

BACKGROUND/AIMS: There are still many important but unclear points regardin g the differential diagnosis and operative indications of cystic lesions of the pancreas with malignant potential. Studies of the clinicopathological and molecular biological characteristics of such diseases are necessary. In this paper, we discuss operative indications for this condition based on a review of the literature and our own experience. METHODOLOGY: Seven cases of serous cystadenoma and 9 cases of mucinous cyst adenoma or cystadenocarcinoma of the pancreas that were operated on or auto psied in our department from 1980 to 1996 were analyzed clinicopathological ly. Small cystic lesions incidentally found in 300 autopsied cases were als o studied. Finally, mucin-producing tumors described in several reports wer e reviewed, and the branch type of this tumor was especially investigated. RESULTS: A marked disappearance of pancreatic acini in the upstream pancrea s was found when serous cystadenoma became large. Papillary projection was histologically found in all of the cases. Tumorous invasion to the intersti tium was suspected in tumors more than 5cm in diameter, and malignancy was reported when tumors were larger than 6cm. As for mucinous cystadenocarcino ma, the patients had a poor prognosis. In 2 of 42 cases with a pseudocyst, small duct cell carcinoma was incidentally found adjacent to the pseudocyst on the duodenal side. With regard to branch-type intraductal papillary neo plasm, 80% of the tumors larger than 4cm were malignant. Most of the small cystic lesions found in elderly autopsy cases were accompanied by hyperplas tic epithelia without evidence of malignancy. CONCLUSIONS: Based on our experience, an operation should be considered and resection is recommended under the following circumstances: 1) cystic lesi ons in the body and tail of the pancreas in middle-aged women; 2) typical s erous cystadenoma larger than 4cm; 3) mucinous cystadenoma of any size; 4) branch-type intraductal papillary neoplasm larger than about 3cm; and, 5) p seudocysts of unknown cause. Small cystic lesions in elderly patients shoul d not necessarily be operated on, but should be followed-up carefully.