The prenatal imaging of a rare congenital intracranial teratoma.

Fetal intracranial teratoma presents a rare and devastating diagnosis. Typically, this condition is first detected during routine prenatal ultrasounds, appearing as an irregular heterogeneous lesion. Further insights are gained through fetal magnetic resonance imaging (MRI), better characterizing the anomaly. The combination of these modalities provides detail-oriented high resolution MRI images, while follow-up ultrasounds capture dynamic growth changes, serving as a cost-effective and easily accessible adjunct. This fast-growing tumor leads to macrocephaly and ventriculomegaly, causing severe distortion of the brain parenchyma. Early detection is crucial for effective fetal management and preventing maternal complications. Unfortunately, treatment options are limited due to the tumor's aggressive nature, typically resulting in fetal demise shortly after birth. Here, we present the sonographic and MRI findings of a congenital intracranial teratoma, reaching massive proportions and replacing the entire cerebral hemisphere.