Detection of serous precursor lesions in resected fallopian tubes from patients with benign diseases and a relatively low risk for ovarian cancer.

The frequency of ovarian cancers in Japan has increased; however, doubts have been raised concerning the mechanism by which high-grade serous adenocarcinomas (HGSCs) arise. Conventionally, HGSC is thought to originate from the ovarian surface epithelium or epithelial inclusion cyst. However, recent data indicate that HGSCs may in fact develop from precursor lesions in the fallopian tube, including epithelia with a p53 signature, serous tubal intraepithelial carcinomas (STICs), secretory cell outgrowths (SCOUTs), and tubal intraepithelial lesions in transition (TILT). Here, we determined the frequency of these fallopian tube precursors in surgically excised samples from 123 patients with benign pelvic diseases. We identified 12 cases with a p53 signature (9.7%), 26 with observable SCOUTs (21.1%), and 4 with TILT (3.2%), but no STIC cases. Although the lifetime risk for developing ovarian cancer is only around 1.4% for women without germ-line mutations, it is important to evaluate the presence of precursor lesions to understand HGSC pathogenesis better. Taken together, salpingectomy appears to be an option for women who are past their childbearing age and plan to undergo elective pelvic surgery. To our knowledge, this is the first study to investigate the presence of these specific precursors post-salpingectomy in low-risk patients.