Coexisting Brenner tumor and struma ovarii in the right ovary: case report and review of the literature.

A bilateral ovarian tumor composed of mixed Brenner tumor and struma ovarii in the right ovary and mature cystic teratoma in the left ovary, is described. Mixed Brenner tumor and struma ovarii is rare; eight cases are reviewed. In this case, in addition to the typical Brenner tumor and struma ovarii, some nests composed of both Brenner tumor and struma ovarii in one nest were found in the right ovarian tumor. Immunohistochemically, the struma ovarii is stained for thyroglobulin, and Brenner nests showed various degrees of positive stain for thyroglobulin, which is a specific finding. Brenner tumor, in this case, may produce thyroglobulin or have a receptor to thyroglobulin or analog of thyroglobulin. The origin of mixed Brenner tumor and struma ovarii may be germ cell, as described in some literature, or the Brenner tumor may be of a metaplastic nature, although the Brenner tumor is fourfold the size of struma ovarii in the case presented.