Ovarian Brenner tumors. II. Malignant

In this study, nine malignant Brenner tumors were reviewed and divided into well and poorly differentiated types. To meet the criteria for malignancy, stromal invasion must be observed. A component of typical benign, metaplastic, and/or proliferating Brenner tumor should be identified. The presence of these latter elements is necessary because the malignant component is often too poorly differentiated to be identified as a Brenner tumor, and a metastatic lesion cannot otherwise be ruled out on pathologic grounds. Well-differentiated tumors often occurred in close relationship to proliferating and occasionally to metaplastic areas, and poorly differentiated ones in relationship to low malignant potential areas. The malignant component may consist of transitional cell, squamous, or undifferentiated carcinoma or an admixture of these. A component of adenocarcinoma may be associated with other malignant elements, but pure mucinous or serous adenocarcinomas would be regarded as separate neoplasms. Although the number of cases is small, the well-differentiated tumors appear to have a better prognosis than the poorly differentiated ones.