[Mature and immature ovarian teratomas: US, CT and MR imaging features].

Mature cystic ovarian teratomas, also called dermoid cysts, are one of the most frequent ovarian tumors of younger female patients and are suggested when a fat-containing cystic tumor is identified on imaging. However, the presence of fat is not pathognomonic for dermoid cyst, and it may also be identified in immature teratomas, whose prognosis and treatment are different. Some imaging features are helpful to differentiate between both tumors, including th epresence of enhancement on CT and MRI. Knowledge of the imaging features of these tumors allows for a confident diagnosis to be made in most cases. A few rare and less typical imaging features should also be recognized.