CT and MR features of struma ovarii

The purpose of this study is to investigate radiologic findings of struma ovarii, and to correlate both CT and MR findings.

MR images of 26 cases were retrospectively reviewed. Post-contrast enhanced T1-weighted images were available in 17 patients. CT images, including seven non-contrast and eleven post-contrast studies, were available for review in 13 cases.

All 26 tumors appeared as well-defined cystic tumors with solid components, which were multilobulated surfaces in 19 and smooth surfaces in seven. Twenty-four was multicystic, whereas two were unilocular. The solid components were recognized as thickened septi or walls in 23 and a mass in three tumors. On T2-weighted images, loculi of prominent low intensity were recognized in 16 tumors. On T1-weighted images, the punctuate foci of high intensity were recognized in 24 tumors in or adjacent to the solid components. Ascites was present in only one lesion. In six of seven cases with non-contrast CT images, high attenuation areas were recognized. In five of these six tumors, high attenuation areas corresponded to the areas of prominent low intensity and the solid components on T2-weighted images. In seven cases with CT, curvilinear calcifications were recognized in the solid components.

Struma ovarii typically presents as a lobulated multicystic lesion with solid components. The tumors frequently include loculi of low intensity on T2-weighted images and punctuate foci of high intensity on T1-weighted images. On CT, high attenuation areas and calcifications in the solid components are common findings.