Sonographische Diagnostik von Dermoidzysten (Sonomorphologie und Vaskularisation)

Purpose: Due to their sonomorphical appearance mature cystic teratomas are often correctly diagnosed ,,at first sight. However the complex and variable architecture of the lesions frequently leads to their classification as malignant if sonographic tumour scores are applied. Material and Methods: In the Department of Gynaecology Hospital at the University of Freiburg, we performed between 1988 and 1996 a preoperative ultrasound examination of 117 cystic teratomas in 110 patients. In 63 of these tumours Colour-Doppler sonography was also used. Results: As typical sonographic markers for the diagnosis of cystic teratomas was used the following criteria: a line pattern in the fluid phase of the tumour (seen in 62 [53%] cases); homogeneous echogenic structure (seen in 102 [82%] cases); shadowing (seen in 50 [43%] cases). 96% of the tumours showed at least one of these markers. In 62% of dermoid plugs with hairs typical sonographic criteria were present. In 25% of the cases with osseous or dental structures characteristics shadowing was observed. The ranking of the sonographic diagnosis was assessed for 754 ovarian tumours including 71 cystic teratomas. The dermoid tumours were predicted with a sensitivity of 94.3%, a specificity of 99.3%, an accuracy of 98.8% and a positive or negative predictive value of 93% and 99.3%, respectively. Using the colour Doppler technique we were able to predict the tumour status of the complex cystic teratomas correctly in 91% and 93% of the cases, respectively, using one of the following parameters: number of tumour arteries, maximum systolic velocity or sum of maximum systolic velocities. This figure dropped to 68% if minimal resistance index was used. Conclusion: Basing on typical markers, sonographic diagnosis of cystic teratomas is very reliable. Colour Doppler sonography is a useful, independent method to supplement determination of the tumour status of teratomas.