[1206] Comparative Analysis of Low Stage Ovarian Carcinomas: Detailed Morphologic Assessment of Stage I and II High Grade Serous Carcinoma as Compared to Other Low Stage Ovarian Carcinoma Subtypes

Elizabeth Morency, Yevgeniy Karamurzin, Mario Leitao, Robert Soslow. Memorial Sloan-Kettering Cancer Center, New York, NY

Background: Recent studies have suggested that many high grade serous carcinomas (HGSCs) that present as ovarian carcinomas may derive from microscopic precursors in the fallopian tube but the majority present at high-stage, complicating detection of the origin of disease. Studying features of low-stage disease may help to provide information relevant to this issue. We anticipate that most non-high grade serous carcinomas will demonstrate features consistent with derivation from precursors located in or transplanted to the ovary and that many will be distributed in a pattern suggesting secondary involvement.
Design: We examined 76 patients with low stage (FIGO I/ II) ovarian carcinoma who underwent primary surgical management at our institution from 1980 to 2000. H&E slides were reviewed and histologic type assigned using Gilks, Soslow et al criteria. Ovarian mucinous, endometrioid, clear cell and HGSCs were included and primary versus metastatic origin was assessed based on the presence or absence of bilaterality, multifocality, surface involvement, size, and pattern of invasion.
Results: Twenty-two cases of HGSC, 30 cases of endometrioid, 11 cases of mucinous and 13 cases of clear cell adenocarcinoma were evaluated and the 54 non-serous carcinoma (NSC) subtypes were grouped for the purposes of comparison. Surface involvement was identified in 14 cases (63%) of HGSCs compared to 7 cases (13%) from the non-serous group. Bilaterality was identified in 12 cases (55%) of HGSCs versus 4 cases (7%) of NSCs. The mean size of the HGSCs was 8.95 cm compared to 13.8 cm for the NSCs. Twelve (55%) cases of HGSC were multifocal compared to 4 cases (7%) of NSC. A significant difference in growth pattern was also identified. Eight cases (36%) of HGSCs showed an infiltrative growth pattern whereas only 12 cases (22%) of NSCs; showing instead a more expansile pattern. Of note, a subset of HGSCs did emerge that fit a more primary pattern. Four cases (18%) of unilateral, unifocal HGSCs without surface involvement and a mean size of 13 cm were identified.
Conclusions: Stage IA HGSC is exceedingly rare. This along with higher rates of “metastatic” features as compared to the non-serous subtypes support the hypothesis that most derive from extraovarian precursors. We also identified a small subset of HGSCs that exhibited a “primary” growth pattern, which lends credence to the hypothesis that some HGSCs arise within ovarian inclusion cysts.
Category: Gynecologic & Obstetrics

Tuesday, March 5, 2013 1:45 PM

Proffered Papers: Section B, Tuesday Afternoon


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