[Prostatic tissue in a cystic teratoma of the ovary]

We report one example of mature cystic teratoma of the ovary containing prostatic tissue, in a 73 year-old female. The tumor is typical and it is composed of well-differentiated derivatives of the three germ layers. Prostatic tissue was an incidental finding in teratoma. This tissue contained ducts and acini in a simple branching pattern similar to that seen in the peripheral zone of the prostatic gland. The immunohistochemical stainings for PSA and PSAP throughout the glandular cells were similar to those present in normal prostate.