Abstract: Serous ovarian carcinoma, serous tubal carcinoma and serous peritoneal carcinoma comprise non-uterine pelvic serous carcinoma. Serous ovarian carcinoma can be divided into low-grade and high-grade subtypes according to cell differentiation. These two subtypes are distinct disease for the extreme variation in clinical manifestation, prognosis and endometrial cysts molecular feature. It was considered that low-grade subtype arises from benign cysts of ovarian like the serous cystadenomas and endometrial cysts by borderline tumors. The origin of high-grade subtype is unclear and believed to arise from ovarian surface epithelium traditionally. Pathological examination of the fallopian tube after risk-reducing salpingo-oophorectomy of BRCA mutation carriers found that serous tubal intraepithelial carcinoma （STIC） was usually present，which may be the precursor lesion for high-grade serous ovarian carcinoma. The same lesion was found at the fimbriae of patients diagnosed of serous tubal or peritoneal carcinoma which sharing the similar clinical and molecular characters to high-grade serous ovarian carcinoma. It was suggested that the above three types of non-uterine serous carcinoma may all arise from the STIC lesion located in fimbriae of uterine tube.

Key words: Neoplasms, cystic, mucinous, and serous, Ovarian neoplasms, Fallopian tube neoplasms