Abstract: Objective：To investigate the clinicialpathoiogy，diagnostic approachs，therapies，and prognosis of struma ovarii. Methods：From Jan. 1994 to Mar. 2012，the data of 32 patients with struma ovarii in the Department of Gynecology in Tianjin Medical University General Hospital，were analyzed retrospectively. Results：Struma ovarii occured within ovarian teratomas at rate of 4.3%（32/745），and the rate of malignant change was 6.25%（2/32）. The average age of the patients was 46.8 years old（range from 22 to 78）. The patients mainly presented as pelvic or adnexal mass，accompanying with hypogastralgia， abdominal distension，ascites，urgent urination，or frequent micturition. The average diameter of turmors was 6.9 cm （range from 3.0 to 15.0 cm）. The mean of CA125 level was 28.6 U/mL，and elevated serum CA125 of 4 cases was detected in different level （range from 38.1-174 U/mL）. There was no feature in image examinations. Final diagnosis based on pathology. No reoccurrence found within mean follow-up of 58 months after operation. Conclusions：Struma ovarii is rare in clinical. Because of no obvious clinical feature，the preoperative misdiagnosis rate is high，but the prognosis is good for most of patients. Meanwhile，it is necessary to pay more attention to these patients with malignant transformation，mixture with brain tissue，or hyperthyroidism.

Key words: Struma ovarii, Diagnosis, Therapy, Prognosis