This study was undertaken to determine if the diagnosis of cystic teratomas of the ovary can be made by experienced sonologists using only specific associated sonographic features.

Two sonologists independently reviewed the sonograms of 252 adnexal masses. For each mass, each sonologist recorded sonographic features using a standardized checklist, which included four descriptions associated with cystic teratomas. From a list of diagnostic possibilities, each reviewer chose one specific conclusion, with emphasis on achieving the highest combination of sensitivity and positive predictive value for any particular diagnosis. The sensitivity, positive predictive value, and positive likelihood ratio for the diagnosis of cystic teratoma were evaluated for each sonographic finding and for each sonologist's interpretation.

Of the 252 masses, 74 cystic teratomas were found, 55 of which showed two or more associated sonographic features. Each reviewer had a 98% positive predictive value with 85% sensitivity for the diagnosis and identification of cystic teratomas (positive likelihood ratio = 152). The positive predictive value was 100% when an adnexal mass had two or more sonographic features associated with dermoid masses. The positive predictive value for individual sonographic features associated with dermoid masses was 80% for a shadowing echodensity, 75% for regionally bright echoes, 50% for hyperechoic lines and dots, and 20% for a fluid-fluid level.

An adnexal mass showing two or more of the sonographic features associated with cystic teratomas can be confidently diagnosed as a cystic teratoma.