Sonographic and clinical characteristics of struma ovarii

Our objective was to evaluate the preoperative clinical, laboratory, and so nographic characteristics of struma ovarii in comparison to ovarian dermoid cysts. A retrospective review of gynecologic patients operated on for matu re cystic teratoma over a 10 year period identified 12 cases of struma ovar y. These cases, combined with 4 additional cases from an earlier report, we re the subject of this study. Results were compared to 32 cases of ovarian dermoid cysts. Ovarian struma ovarii occurred in 12 (4.8%) of 251 cases of ovarian dermoid cysts. Most patients were premenopausal, and the mean lesio n diameter was 57.3 mm (range, 30-95 mm). Struma ovarii occurred more frequ ently (68.8%) in the right adnexa and was seen with a normal CA-125 level. Blood flow, assessed by Doppler ultrasonography, was located in the center of the lesion in all cases of struma ovarii. Rare cases were seen with elev ated tumor markers and low resistance blood flow With regard to dermoid cys ts, blood flow had a higher resistive index. In addition, no blood flow cou ld be detected from the center of the echoic lesion in dermoid cysts (P < 0 .0001). In summary, it is difficult to distinguish between struma ovarii an d dermoid cysts on the basis of their sonographic appearance. Nevertheless, Doppler flow may aid in the preoperative diagnosis of struma ovarii. Blood flow signals, detected from the center of the echoic lesion, and low resis tance to flow may be more common in struma ovarii.