[Cystic neoplasms of the pancreas. Pathologico-anatomic study of 15 pancreatic tumors].

Cystic neoplasms of the pancreas are rare and comprise about 2% of all exocrine tumors. Clinically they manifest as an abdominal mass and may result in gastrointestinal or biliary obstruction or remain symptomless. Fifteen such tumors from the Institute of Pathology, University Hospital, Zürich, are presented. Eleven of them are autopsy findings and 4 are operative specimens. They can be divided into two distinct groups described as (A) microcystic adenomas, composed of many small cysts lined by cuboidal cells containing glycogen but no mucin, and (B) as mucinous cystic tumors formed by larger cystic spaces lined by tall, columnar, mucin-producing cells. Microcystic adenomas are invariably benign, whereas the majority of mucinous tumors show focally malignant epithelium. We had no difficulty in distinguishing between these two forms. Nine of the 11 microcystic adenomas were autopsy findings, and we have follow-up information only for two patients. Histologically, however, no malignant change was seen in a microcystic adenoma but was found in 3 of the 4 mucinous tumors. The cell of origin of the mucinous tumors must be the lining cell of the excretory ducts. Because of histological and ultrastructural similarity, the cell of origin of the microcystic adenoma is thought to be the centroacinar cell. The question arises whether these latter tumors, not infrequently combined with cysts or cystic tumors in other organs, should not rather be classified as hamartomas.