Papillary cystadenoma.

A rare case of a papillary cystadenoma, mucous-cell type, in the lower lip of a 73-year-old male is presented. The tumor consisted of many small cysts with multiple papillary projections into their cystic spaces. The projections and cyst walls were lined with pseudostratified mucous-cell epithelium. Clinically and histologically, the present papillary cystadenoma was considered as a true tumor originated from the ducts of minor salivary glands. There exists only one case report of a papillary cystadenoma with adequate description and photomicrographs in the Japanese dental literature.