At 24 weeks of gestation, an intracranial cystic lesion of 3 cm diameter, without further associated foetal malformations, was detected by ultrasound in a 25-year old nullipara prima gravida, during routine prenatal care. Within 5 weeks, the cystic mass developed into a predominantly solid tumour located at the 3rd ventricle, showing patterns of a rapidly growing malignant intracerebral process. At 29 weeks of gestation, pregnancy was terminated by sectio parva because of a progressive hydrocephalus with a biparietal diameter of 10.2 cm. Autopsy confirmed a malignant teratoma. Foetal intracranial teratomas are rare. Diagnosis and therapy should be carried out in perinatal centres.