[1174] A Clinicopathological and Immunohistochemical Study of 54 Cases of Dysgerminoma and Gonadoblastoma

Anthony N Karnezis, John R Jalas, Yunmin Li, Yun-Fai Chris Lau, Lee-May Chen, Teri A Longacre, Charles J Zaloudek. UCSF, San Francisco, CA; Veterans Affairs Medical Center, San Francisco, CA; Stanford University, Palo Alto, CA; St. John's Health Center, Santa Monica, CA

Background: In the ovary, dysgerminoma (DG) most often develops as a pure tumor, a mixed germ cell tumor or from a gonadoblastoma (GBL) in a patient with dysgenetic gonads. The purposes of this study are to assess the clinical, gross, and histologic features of DG and GBL and determine the best immunohistochemical markers to delineate the types of germ cell neoplasia present in these tumors.
Design: We searched the Pathology records for cases of DG and GBL from 1980 to 2011. Immunohistochemical stains for OCT4, SALL4, NANOG, PLAP, TSPY, CD117, D2-40, AFP, Glypican-3, HCG, AE1/AE3 and CAM5.2 were performed in all tumors. GBL were also stained for WT1, inhibin A (INHA), calretinin, SF1 and CK18. Stains were scored for extent (percent) positivity (0-4) and intensity (0-3), and a composite score (CS) was calculated as the product of the two scores (0-12).
Results: We identified 54 tumors: 32 pure DG, 9 DG mixed with other germ cell elements, 6 DG arising in GBL, and 5 pure GBL. Mean age was 21 years for patients with DG (range 5-51) and 16 years for patients with GBL (range 11-21). Mean DG size was 16 cm; mean weight, 1.3 kg. For DG patients, 27 patients (57%) were stage I, 2 (4%) stage II, 12 (26%) stage III, 1 (2%) stage IV, and 5 (11%) had unknown stage disease. Mean mitotic activity in DG was 22 per 10 HPF (median 18, range 0-61). The most sensitive markers for DG were OCT4 (CS=11.6), D2-40 (CS=10.9), SALL4 (CS=9.6), NANOG and CD117 (CS=8.6) and PLAP (CS=6.8). Similarly in GBL, germ cell nests were best highlighted by OCT4 (CS=11.6), CD117 (CS=11.5), D2-40 (CS=11.4), SALL4 (CS=9.5), PLAP (CS=8) and TSPY (CS=7.5). AE1/AE3 (CS=6.4) and INHA (CS=4.7) were the most sensitive markers of sex cord-stromal cells in GBL. Interestingly, the Y chromosome-specific protein TSPY was expressed in 4 (10%) DG not associated with GBL. It was exclusively cytoplasmic in contrast to its cytoplasmic and nuclear localization in GBL.
Conclusions: OCT4, D2-40 and CD117 are the most sensitive markers for malignant germ cells in DG and GBL. AE1/AE3 and INHA are the most sensitive markers of sex cord-stromal cells in GBL. The expression of TSPY in some pure dysgerminomas raises the possibility that these patients may harbor regions of the Y chromosome.
Category: Gynecologic & Obstetrics

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 203, Tuesday Morning


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