Nonmucinous cystadenomas of the pancreas with pancreatobiliary phenotype and ovarian-like stroma.

Among 31 benign cystic neoplasms of the pancreas diagnosed as mucinous cystadenomas, we identified 9 (29%) cases of nonmucinous cystadenomas with a pancreatobiliary phenotype and an ovarian-like stroma. Although both cystic tumors belong to the same family, they should be separated because their epithelial lining and cyst fluid are different. The lining cells of the nonmucinous cystadenomas consisted of a single layer of cuboidal cells, similar to the epithelial cells of the normal pancreatic ducts, and were not dysplastic (90%-100% of the lining cells). The cyst fluid was described as serous or clear. The remaining 22 classical mucinous cystadenomas, lined predominantly by mucinous and foveolar epithelium, revealed focal pancreatobiliary epithelium in 86% of the cases, and 6 pancreatic invasive mucinous cystadenocarcinomas failed to show pancreatobiliary differentiation. We believe that these nonmucinous cystadenomas of the pancreas represent a distinctive subset of cystic neoplasms of the pancreas that probably have no malignant potential.