Ovarian teratomas: Tumor types and imaging characteristics

Ovarian teratomas include mature cystic teratomas (dermoid cysts), immature teratomas, and monodermal teratomas (eg, struma ovarii, carcinoid tumors, neural tumors). Most mature cystic teratomas can be diagnosed at ultrasonog raphy (US) but may have a variety of appearances, characterized by echogeni c sebaceous material and calcification. At computed tomography (CT), fat at tenuation within a cyst is diagnostic. At magnetic resonance (MR) imaging, the sebaceous component is specifically identified with fat-saturation tech niques. The US appearances of immature teratoma are nonspecific, although t he tumors are typically heterogeneous, partially solid lesions, usually wit h scattered calcifications. At CT and MR imaging., immature teratomas chara cteristically have a large, irregular solid component containing coarse cal cifications. Small foci of fat help identify these tumors. The US features of struma ovarii are also nonspecific, but a heterogeneous., predominantly solid mass may be seen. On T1 - and T2-weighted images, the cystic spaces d emonstrate both high and low signal intensity. Familiarity with the US, CT, and MR imaging features of ovarian teratomas can aid in differentiation an d diagnosis.