Immature ovarian teratoma represents less than 1% of ovarian teratomas. It is an uncommon ovarian germ cell tumor, which differs from the far more common mature ovarian teratomas (dermoid cysts). It is usually seen in young females, as in this example. It appears on CT as a large cystic lesion with solid components that shows coarse calcifications and streaks of fat.

Immature ovarian teratoma can be associated with another mature or immature cystic teratomas ¹.