Fallopian tube abnormalities in uterine serous carcinoma

Uterine serous carcinoma (USC) is presumed to arise from endometrial intra-epithelial carcinoma (EIC), whereas tubo-ovarian high-grade serous carcinomas have similar precursor lesions in the Fallopian tube, i.e. serous tubal intra-epithelial carcinoma (STIC). The presence of Fallopian tube abnormalities and their clonal relationship to the concurrent USC was investigated.

In this multicenter study, all patients treated for USC between 1992 and 2017 were retrospectively identified. Histopathological diagnosis of USC, EIC and STIC was revised by an expert pathologist. Additionally, all Fallopian tube sections were immunohistochemically stained (p53 and Ki-67). Fallopian tube abnormalities were classified as either p53 signature, serous tubal intra-epithelial lesion (STIL) or STIC. The USCs and Fallopian tube abnormalities were analyzed by targeted next-generation sequencing.

In 168 included patients, Fallopian tube abnormalities were found in 27.4% (46/168): p53-signatures in 17.9% (30/168), STILs in 3.0% (5/168) and STICs in 6.5% (11/168). In subgroup analysis, STICs were found in 9.5% (11/115) of patients with at least one section of the fimbriated end embedded. Next-generation sequencing showed identical TP53-mutations in the STIC and corresponding USC.

In conclusion, the presence of Fallopian tube abnormalities was shown in a high percentage of patients with USC, representing either true precursor lesions or metastasized disease.