[1005] Reproducibility of Histological Diagnosis of Ovarian Clear Cell Adenocarcinoma

T Kiyokawa, T Moriya, H Ishikura (deceased), SG Silverberg. Jikei University School of Medicine, Tokyo, Japan; Kawasaki Medical University, Kurashiki, Japan; Chiba University School of Medicine, Chiba, Japan; University of Maryland School of Medicine, Baltimore, MD

Background: Ovarian clear cell adenocarcinoma (CCA) is relatively common in Japan compared to Western countries. It is often associated with endometriosis or an adenofibromatous component (AF), and one recent study suggested that the latter might be a factor for less aggressive behavior. Because its biological behavior including chemotherapy-resistance is different from ovarian cancer of other histological types, accurate pathological diagnosis is crucial for patient management. This study was carried out to examine reproducibility of the histological diagnosis of ovarian CCA. Frequencies of coexisting AF and endometriosis were also explored.
Design: Ninety-nine cases (age: 38-72 yrs, average 55.4 yrs; 50 FIGO stage I, 13 stage II, 30 stage III, 6 stage IV) of ovarian tumors submitted from 36 institutions for a Japanese Gynecologic Oncology Group (JGOG) clinical study with a referring institution's pathologist's diagnosis of CCA were reviewed by a panel of 4 gynecologic pathologists. Representative H-E slides were assessed independently by 3 of the panelists using WHO criteria before re-examination under a multihead-microscope by 4 of them. The panel diagnosis was based on diagnostic concordance by at least 3 of the 4 panelists.
Results: The panel diagnosis was CCA in 93 cases (94%). The rest included 2 cases of mixed carcinoma with minor component of CCA, and one each of clear cell borderline tumor, transitional cell carcinoma, endometrioid adenocarcinoma, and serous borderline tumor. Of 93 confirmed cases of CCA 13 (14%) were associated with AF and 15 (16%) with endometriosis. There was no association of either of these features with lower stage CCA.
Conclusions: Reproducibility of referring institutions' pathologists' diagnosis of ovarian CCA by a panel of gynecologic pathologists is excellent. Our results also suggest that the frequencies of AF and endometriosis associated with CCA are at least 14%, and 16%, respectively, and that these associated lesions do not correlate with tumor stage.
Category: Gynecologic

Wednesday, March 11, 2009 9:30 AM

Poster Session V # 149, Wednesday Morning