Abstract: Objective:To analyze the clinical features of ovarian fibrothecoma complicated with ascites and high level of CA125, and to explore the causes of elevated CA125 level and its significance in identifying benign and malignant ovarian tumors. Methods:The clinical data of one patient with varian fibrothecoma complicated with ascites and high level of serum CA125;combined with relevant literature review, the clinical characteristics, diagnosis and treatment process, and the significance of CA125 in the differential diagnosis of benign and malignant ovarian tumors were analyzed. Results:The patient was admitted to hospital due to vaginal bleeding for 4 months and pelvic mass for 1 month. The diagnosis result was pelvic and abdominal mass arising from ovarian according to the preoperative color Doppler ultrasound, enhanced CT, serum CA125 level and physical examination,and was highly suspected as ovarian malignant tumor. Surgery treatment was performed; based on the intraoperative rapid pathological results and postoperative slow pathology, the patient was diagnosed as ovarian fibrothecoma; the operation was successful. The patient recovered well and discharged from hospital.The serum CA125 level was decreased to the normal range 1 month after operation. Conclusion:Identification and quantitative analysis of the glycosylation modification and specific glycan structure of CA125 from different sources can significantly improve the diagnostic specificity of CA125 for benign and malignant ovarian tumors.

Key words: ovarian fibrothecoma, ovarian neoplasms, carbohydrate antigen 125, ascites