Doppler flow characteristics of dermoid cysts: unique appearance of struma ovarii.

The purpose of our study was to evaluate the Doppler flow characteristics of ovarian dermoid cysts. In 70 women (mean age, 38.7 +/- 14.6 years), 78 ovarian lesions with mean diameter of 48.9 +/- 28.4 mm and preoperative sonographic diagnosis of dermoid cyst of the ovary were evaluated prospectively by Doppler flow sonography; these cysts were eventually removed surgically. The findings were compared to the postoperative histologic results. In 74 lesions (eight cases were bilateral), when blood flow patterns were detected (detection rate of 24.3%) they were obtained only from the ovarian tissue surrounding the dermoid cavity, with a mean resistive index of 0.6 +/- 0.1 (range, 0.4 to 0.76). In four cases, which were proved postoperatively to be struma ovarii, blood flow was detected not only from the cyst capsule but also from the centrally positioned solid area (dermoid tissue), with a mean RI of 0.565 +/- 0.08 (range, 0.509 to 0.667). Dermoid cysts of the ovary are devoid of blood flow, with flow detection rate being only 24.3% from the cyst capsule. When apparently vascularized solid tissue is detected in the central part of a sonographically suspected benign cystic teratoma, struma ovary is highly suspected.