Endometrioma With Calcification Simulating a Dermoid on Sonography

Several investigators have explored the sonographic diagnostic criteria of endometriomas. Endometriomas have characteristic findings on sonography. Diffuse dispersion of low-level echoes within a cystic mass is thought to be the most useful diagnostic feature. Mais et all documented sensitivity of 88% and specificity of 90% in differentiating endometriomas from other ovarian masses with endovaginal sonography. Patel et al 2 identified diffuse low-level internal echoes in 95% of endometriomas and 19% of nonendometriomas. The presence of multilocularity or hyperechoic wall foci further increased the possibility of a given mass being an endometrioma. 2 They postulated that these two findings would have the highest diagnostic value in distinguishing endometriomas from other adnexal masses. This report presents an unusual case in which a large cystic adnexal mass showed a fluid-fluid level and a large, discrete calcification. A sonographic diagnosis of a dermoid was made; however, it proved to be an endometrioma on magnetic resonance imaging (MRI), which was later confirmed with laparoscopic removal and a pathologic report.