Sonography of ovarian tumors: predictability of tumor type.

One hundred six ovarian neoplasms were evaluated with respect to size, echogenic characteristics, and percentage of echogenic material to determine if sonography could differentiate between malignant and benign tumors and if histology could be determined. This study indicates that anechoic lesions have high likelihood of being benign tumors, usually mucinous cystadenomas or serous cystadenomas. As the percentage of echogenic material increases, the likelihood of malignancy also increases. There are two exceptions to this rule. The first is lesions with very echogenic foci, which are virtually always benign teratomas. The second is groups of tumors that are totally or near-totally echogenic. These are actually less likely to be malignancies than mixed-density tumors that have a large anechoic component. In mixed-echogenicity tumors that are not teratomas, there was no way of distinguishing between benign and malignant lesions with an acceptable degree of accuracy in an individual case. Also, with the exception of teratomas, histology could not be determined. It should be noted that in the postmenopausal patient, the maximum size of a normal ovary is 2 X 1.5 X 0.5 cm. An adnexal mass larger than this must be considered suspicious of a neoplasm.