[1210] Additional Insights on Ovarian Low Grade Serous Carcinoma: A Study of Consecutive Cases with Primary Surgery Performed at a Single Institution

E Okoye, E Euscher, A Malpica. MD Anderson Cancer Center, Houston, TX

Background: Low grade serous carcinoma(LGSC) is a subtype of ovarian carcinoma (OC) with distinct pathogenesis, pathologic features and clinical behavior. Although several studies have covered different aspects of this entity, no study has evaluated this disease in patients (pts) who have received their primary surgery at a single institution. In this study we present our experience with a cohort of such cases.
Design: To determine incidence of LGSC, all cases of OC from 1995-2010 were recorded. From 2005-2010, all LGSC and high grade serous carcinomas (HGSC) were also extracted to determine survival differences. Pt age, stage and outcome were recorded. All available H&E slides were reviewed for presence/absence of serous borderline tumor (SBT), presence/absence of micropapillary/cribiform pattern (MP/CP), architectural pattern in the invasive component, presence/absence of desmoplasia or fibrosis.
Results: Of 471 OC from 1995-2005, 22 LGSC were identified (4.7%). In addition 11 LGSC were collected from 2005-2010. Mean age for LGSC was 52 yrs (range:19-70;17.5% <40) and 62 yrs for HGSC (range:38-90;1.6% <40). LGSCs were staged as follows:Stage I (2), Stage III (23), Stage IV (8). 28 LGSC had concurrent SBT, usually MP/CP. Of cases with SBT, SBT usually comprised > 50% of the tumor. The architectural pattern of invasion included small stroma poor papillae (92.3%), cribiform nests (73.1%), elongated papillae (34.6%), medium sized papillae with fibroconnective tissue (FCT) core (34.8%), large papillae with FCT core (19.2%), solid nests (15.4%), single cells (7.7%), desmoplasia (46.2%) and fibrosis (65.4%).Follow up from 13 mos to 195 mos (mean 67.2) was available for 30/33 LGSC:dead of disease, 18 pts (60%);dead of other cause, 1 pt (3.3%);alive with disease, 5 pts (16.7%);no evidence of disease, 6 pts (20%). For 185 HGSC with follow up (7 days to 169 mos, mean 57):dead of disease 132 pts (71.4%):dead of other cause, 3 pts(1.6%);alive with disease, 21 pts(11.3%);no evidence of disease, 29 pts (15.7%).
Conclusions: LGSC is a rare tumor accounting for 4.7% of all primary OC at a single institution. LGSC can present over a wide age range, and is more likely to occur at a younger age than pts with HGSC. Most of the cases of LGSC are associated with a SBT, particularly with MP/CP pattern. Most of the cases with associated SBT with MP/CP pattern had an invasive component histologically similar to what was seen intracystically. The majority of pts with LGSC present at advanced stage disease, and have a survival advantage over pts diagnosed with HGSC.
Category: Gynecologic & Obstetrics

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 166, Wednesday Morning


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