Background: Borderline Brenner tumor of the ovary is a rare entity characterized by papillary structures with a fibro-vascular core, covered by a transitional epithelium, and by the absence of stromal infiltration. It is associated, by definition, with a benign component of Brenner tumor.
Case: We report a case of a 68-year-old woman, with a right ovarian mass, whose morphology and immuno-profile were consistent with the diagnosis of a borderline Brenner tumor. Immunohistochemistry carried out on selected markers may help to formulate the diagnosis, more than the molecular analyses.