Struma ovarii mimicking a benign multicystic ovarian tumor: MR imaging in one case

Struma ovarii is a rare form of mature teratoma of the ovary. A case of struma ovarii is presented with magnetic resonance (MR) imaging and pathologic findings. MR imaging showed a multiloculated cystic adnexal mass with well-defined margin and septum. Internal cystic spaces presented homogeneous signal intensity of fluid content in both T1-weighted and T2-weighted images. Subtle contrast enhancement was depicted in internal septi. Imaging features were indistinguishable from benign multicystic ovarian tumor, and different from the reported cases in the literature.