[1188] Site of Origin and High-Grade Pelvic Serous Carcinoma

Douglas I Lin, Eleanor Y Chen, Marisa R Nucci, Christopher P Crum. Brigham and Women's Hospital, Boston, MA

Background: Although classified as "ovarian cancers", the origin of high grade serous carcinomas in the pelvis has been controversial. Recent studies implicate the distal oviduct in a significant percentage of these tumors by the presence of a serous tubal intraepithelial carcinoma (STIC). However, the magnitude of the role played by the fallopian tube remains unclear. We performed a detailed analysis of consecutive cases of serous cancer to determine 1) the maximum number of cases that could be assigned to a non-tubal source by exclusionary criteria and 2) if there was immunohistochemical evidence of an origin in the ovary.
Design: Consecutive cases of high-grade carcinoma accessioned between 2005 and 2007 were analyzed. Reports were scrutinized for whether the distal fallopian tubes were completely analyzed. Cases containing STIC or in which the fimbria could not be fully examined to exclude STIC, were placed in the non-exclusionary category. Cases in which the distal tubes were reported examined and were negative were systematically reviewed to confirm this and exclude STIC. In a separate subset of cases in which both the fimbria were visualized and STIC excluded, the ovaries were immunostained for PAX2 and p53 to identify normal PAX2 positive epitheium in continuity with adjacent p53 positive or PAX2-null cancers or putative precursor epithelium (either PAX2-null or p53 positive).
Results: 203 cases of high-grade carcinoma were identified of which 143 (70%) either reported a STIC or did not identify both fallopian tubes. Of the remaining 60, 34 were availble for review. Of these, 9 contained inadequate or no fimbria in the tubal tissue blocs, 5 contained a STIC, and 16 contained negative fimbrial histology from both the right and left fallopian tubes. Analysis of the ovaries from 20 cases with no clear tubal primary revealed PAX2-null and p53-positive surface serous carcinomas. However, in no case was a carcinoma detected in continuity with either normal or immunohistochemically altered (PAX2-null, p53+) mullerian epithelium, in keeping with surface implantation rather than de-novo neoplastic change.
Conclusions: In approximately 16% of high-grade pelvic mullerian carcinomas, both fimbria can be identified and both will be histologically benign. Analysis of the ovarian cortices do not implicate a source in the ovarian surface epithelium using the existing precursor models described for the fallopian tube. The possibility of other origins and the impact of meticulous sampling the oviduct will be discussed.
Category: Gynecologic & Obstetrics

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 142, Tuesday Afternoon


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