Ovarian serous cystadenofibroma with signet ring-stromal cells: report of 2 cases.

We report 2 ovarian serous cystadenofibromas with signet ring cells within the stromal component. The signet ring-stromal cells were widespread in 1 case and focal in the other. Immunohistochemically, they were negative with cytokeratin and other epithelial markers and positive with mesenchymal markers. The occurrence of signet ring-stromal cells in ovarian serous cystadenofibromas is an unusual pseudoneoplastic phenomenon, which has not been reported previously, although signet ring cells may occur within a variety of ovarian stromal neoplasms, including fibromas, sclerosing stromal tumors, and signet ring-stromal tumors. In reporting these cases, we review ovarian stromal neoplasms and other lesions with signet ring cells.