Prostatic tissue in mature cystic teratomas of the ovary: a report of four cases, including one with features of prostatic adenocarcinoma, and cytogenetic studies.

Four cases of mature cystic teratoma that contained prostatic tissue are reported. The ovarian tumors occurred in patients from 17 to 38 (mean 31) years of age and had no unusual clinical or gross aspects. The microscopic findings for the most part were typical of a mature cystic teratoma, but they also contained foci of prostatic tissue that ranged from 0.2 to 1.9 cm in greatest dimension. In these areas there was a lobular arrangement of medium-sized acini lined by cuboidal to columnar cells with pale cytoplasm and round nuclei with inconspicuous nucleoli except focally in one case as noted below. Basal cells were seen focally. The prostatic acini lay in a paucicellular fibromuscular stroma. In two cases thick layers of disorganized smooth muscle covered by transitional-like pseudostratified epithelium, resulting in an appearance resembling fetal bladder wall, were present next to the prostatic glands. One tumor also contained prostatic-type acini, which haphazardly infiltrated the stroma over an area approximately 5 mm in maximal dimension. The acini, a few of which contained intraluminal flocculent eosinophilic material, were lined by cells with eosinophilic to amphophilic focally granular cytoplasm and had nuclei that were enlarged compared with the benign-appearing, prostatic-type acini in the four cases and had focally prominent nucleoli. Basal cells were not identified in these infiltrating glands. Grading this focus according to the approach in the prostate, the morphology was that of a Gleason grade 3 of 5 adenocarcinoma. Immunohistochemical stains of the putative prostatic epithelial cells confirmed their nature by showing immunoreactivity for prostatic-specific antigen in the lining epithelial cells in all four cases and for prostatic-specific acid phosphatase in the one case tested. The high molecular cytokeratin stain, 34betaE12, highlighted basal cells to a variable extent in the three cases containing only benign prostatic tissue. Material was not available to immunostain for basal cells in the case with carcinoma. Cytogenetic studies were performed in two cases and showed that the great majority of the nuclei of the nonprostatic and prostatic tissue had an XX karyotype but from 3% to 5% of the nuclei displayed trisomy for the X chromosome. A small number of cases of prostatic tissue in ovarian teratomas have previously been documented but none had morphologic features of carcinoma.