[1088] Immuhistochemical Profile of Ovarian Malignant Germ Cell Tumors: Comprehensive Analysis of 14 Markers in 56 Cases.

Joema F Lima, Gary L Keeney, Fabiola Medeiros. Mayo Clinic, Rochester, MN

Background: Malignant germ cell tumors (mGCTs) still present several diagnostic challenges resulting from diversities in histologic types. Several immunohistochemical markers have been used to aid in the diagnosis of mGCTs. Most of the data available was generated in testicular mGCTs. There is a shortage of literature pertaining specifically to the ovaries. Intuitively, mGCTs of the ovaries are expected to have the same immunoprofile as the ones occurring elsewhere. However, this question has not been specifically addressed. The objective of this study is to present a panorama of the pattern of expression of the most commonly used markers in mGCTs occurring in the ovaries.
Design: An immunohistochemical panel of 14 markers was evaluated in 56 mGCTs of the ovaries selected from the in-house and consultation archives of the Mayo Clinic from 2003 to 2010. The study comprises 23 dysgerminomas, 13 yolk sac tumors, 12 immature teratomas, 3 choriocarcinomas and 5 mixed germ cell tumors. Immunohistochemistry was performed in paraffin-embedded tissue sections with antibodies directed against keratin AE1/AE3, AFP, CAM5.2, OCT-4, D2-40, KIT, PLAP, inhibin, calretinin, MIB-1, synaptophysin, chromogranin, GFAP and hCG.
Results: The median age of the patients was 24 years old (range 9 to 58). Tumor size ranged from 2.3 to 29 cm. All dysgerminomas were diffusely positive for OCT4, KIT, PLAP and D2-40; less than 10% stained for CD30 and less than 5% for AE1/AE3, CAM5.2 and hCG. Yolk sac tumor was the only lesion positive for AFP; a diffuse pattern was present with the exception of 2 cases that showed focal expression. All yolk sac tumors were also positive for AE1/AE3 and CAM5.2; KIT was expressed in 84,6%, PLAP in 77%, D240 in 38,4%, OCT4 in 18% and inhibin in 7,6% of cases. All choriocarcinomas stained positively for hCG and keratins; two were also positive for inhibin and one for CD30. All immature teratomas with the exception of one case were positive for both or either synaptophysin and GFAP; chromogranin was expressed in 1/3 and calretinin in 1/4 of cases. Only one of the mixed mGCT contained embryonal carcinoma, which was diffusely positive for CD30, OCT4, PLAP, D2-40 and keratins, and negative for KIT and inhibin. The other mixed mGCTs showed dysgerminoma, yolk sac and immature teratoma components, which had an immunoprofile similar to the pure tumors in these categories.
Conclusions: The immunohistochemical profile of ovarian mGCTs is similar to the one described for mGCTs of the testis; and, therefore, it can be used in this setting with the same level of reliability.
Category: Gynecologic & Obstetrics

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 129, Tuesday Afternoon


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