Objective To explore the clinical manifestations and ultrasound imaging features of primary high-grade serous carcinoma of the fallopian tube (PHGSC-FT) under the new pathological criteria.

Methods A retrospective study was conducted on 45 PHGSC-FT patients diagnosed by postoperative pathology at the Obstetrics & Gynecology Hospital of Fudan University from April to June 2023. Clinical data, ultrasound imaging characteristics, and prognosis were systematically analyzed.

Results The age of patients was (56.2±10.1) years, with postmenopausal women accounting for 68.9%. The main clinical symptoms were abdominal pain and (or) distension (53.3%), pelvic mass (31.1%), and abnormal vaginal discharge (11.1%). Preoperative ultrasound revealed that 40 cases presented as solid pelvic or abdominal masses, while 5 cases involved widely disseminated small lesions not describable by ultrasound; 70.0% of lesions had irregular shapes. Intraoperative findings showed that the primary lesions were located in the ovary in 27 cases (60.0%), fallopian tube in 7 cases (15.6%), extra-adnexal pelvic in 6 cases (13.3%), and widespread disseminated lesions in 5 cases (11.1%). The accuracy rate of ultrasound localization was 82.2%, and the accuracy rate for benign and malignant differential diagnosis was 75.6%. Serum carbohydrate antigen 125 (CA125) levels were significantly lower in patients whose major lesion was located in the fallopian tube than in those with lesions outside the fallopian tube (P＝0.001). FIGO stage Ⅰ: 4 cases (8.9%), stage Ⅱ: 10 cases (22.2%), stage Ⅲ: 23 cases (51.1%), and stage Ⅳ: 8 cases (17.8%), with 3-year survival rates of 75%, 80%, 56.5%, and 50%, respectively.

Conclusions PHGSC-FT predominantly occurs in postmenopausal women, and its biological behavior is characterized by “small primary lesion–large metastatic lesion”. Prognosis is related to FIGO stage. Ultrasound demonstrates high accuracy in localization of large lesions and in determining benign versus malignant nature.