MALIGNANT BRENNER TUMOR WITH PERITONEAL METASTASIS

A case of malignant Brenner tumor with peritoneal metastasis in a 67‐year‐old woman was reported. The multilocular cystic tumor of right ovary was 420 g in weight, and their cystic walls were covered with multilayered tumor cells showing papillary pattern very frequently. The tumor was histologically transitional cell carcinoma with occasional glandular structures but no squamous differentiation corresponding to grade 2 or 3 urinary bladder carcinoma. The pattern of benign Brenner tumor was not Identified, but there was some area of proliferating Brenner tumor. Immunohistochemically, carcinoembryonic antigen was detected in several tumor cells, especially in the intercellular spaces among them, and cytokeratin was detected only in some tumor cells. Ultrastructurallly, the malignant Brenner tumor shared many common features with the benign one and also bladder tumor. Intercellular spaces with microvilli were frequently found and thought to be important for diagnosis. The morphologic criteria of this rare tumor are discussed.