Serous cystadenoma of the pancreas with atypical cells. Case report.

CONCLUSIONS

Serous cystadenomas of the pancreas may have the biologic ability to undergo malignant transformation.

BACKGROUND

It is generally recognized that: serous cystadenomas of the pancreas are benign and that their malignant potential is low.

METHODS

A serous cystadenoma of the pancreas was resected from a 53-yr-old woman. In the central portion of the tumor, papillary structures were found on the cyst wall. Immunohistologic studies using antibodies to carbohydrate antigen 19-9, carcinoembryonic antigen, and proliferating cell nuclear antigen were performed to determine the malignant potential of this tumor.

RESULTS

On histology, most tumor cells were positive for periodic acid-Schiff but were negative for periodic acid-Schiff after diastase digestion and Alcian blue, a staining pattern typical of serous cystadenomas. The cells found in the papillary structure of the cyst wall were mildly atypical. These cells were stained with antibodies to carbohydrate antigen 19-9, carcinoembryonic antigen, and proliferating cell nuclear antigen, indicating that the cells comprising the papillary structure were proliferating more rapidly than cells in other parts of the tumor and strongly suggesting that the cells are premalignant.