Original ArticlesIncidental Nonuterine High-grade Serous Carcinomas Arise in the Fallopian Tube in Most Cases Further Evidence for the Tubal Origin of High-grade Serous CarcinomasGilks, C. Blake MD*; Irving, Julie MD†; Köbel, Martin MD‡; Lee, Chenghan MD, PhD§; Singh, Naveena FRCPath∥; Wilkinson, Nafisa FRCPath¶; McCluggage, W. Glenn FRCPath#Author Information *Department of Pathology, Vancouver General Hospital and University of British Columbia, Vancouver †Department of Pathology, Royal Jubilee Hospital, Victoria, BC ‡Department of Pathology, Calgary Laboratory Services and University of Calgary, AB §Department of Pathology, Royal Alexandra Hospital and University of Alberta, Edmonton AB ∥Department of Cellular Pathology, Barts Health NHS Trust, London ¶Department of Histopathology, St James’s Hospital, Leeds #Department of Pathology, Belfast Health and Social Care Trust, Belfast, United Kingdom Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website, www.ajsp.com. Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: C. Blake Gilks, MD, FRCPC, Department of Pathology, 1st Floor JPPN, Vancouver General Hospital, Rm 1259, 910 West 12th Ave, Vancouver, BC, Canada V5Z 1M9 (e-mail: [email protected]). The American Journal of Surgical Pathology: March 2015 - Volume 39 - Issue 3 - p 357-364 doi: 10.1097/PAS.0000000000000353 Buy SDC Metrics Abstract Most nonuterine high-grade serous carcinomas (HGSCs) in women with hereditary breast and ovarian cancer syndrome, due to germline BRCA1/2 mutation, arise in the fimbria of the fallopian tube. However, the site of origin of sporadic HGSC, which is usually widely disseminated at presentation, is not well established. We sought to characterize cases of HGSC discovered incidentally in patients not known to be at high risk, in order to determine the site distribution and possible origin of sporadic HGSC. Incidental microscopic, non–mass-forming cases of serous tubal intraepithelial carcinoma or HGSC in salpingo-oophorectomy specimens in which the tubes and ovaries had been extensively examined were identified. No patients were known or suspected BRCA1/2 mutation carriers. Twenty-one cases were identified (mean age: 57 y). Surgery was for benign disease (n=15), uterine endometrioid adenocarcinoma or atypical hyperplasia (n=3), bladder carcinoma (n=1), or ovarian serous borderline tumor (n=2). In 16 of 21 cases, the lesion was confined to the fallopian tube (unilateral in 14 cases, bilateral in 2). There was serous tubal intraepithelial carcinoma in all cases and invasive HGSC into the underlying lamina propria in 8 of these 16 cases; the invasive focus measured 1.3 cm or less in every case. In the remaining 5 cases, there was fallopian tube mucosal and ovarian involvement; in 2 of these cases, there was also microscopic peritoneal involvement. Sporadic cases of nonuterine HGSC arise in the fallopian tube fimbria in a large majority of cases, providing further evidence for the tubal origin of these neoplasms. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.