Introduction Congenital intracranial tumours constitute 0.5%–1.5% of childhood brain tumours and most of them are immature teratoma. The cystic or calcified structure of tumour can be evaluated with prenatal ultrasonography, the size/location of tumour can be assessed and differentiated from hematoma with magnetic resonance imaging (MRI). The definite diagnosis can be made with histopathological examination. Even if the tumour is diagnosed prenatally, the prognosis of these tumours is very poor. In this case report, a premature infant, detected a giant intracranial mass prenatally and diagnosed with immature teratoma by histopathological examination postnatally, is presented.

Case A 29 week estimated gestational age, twin male fetus were delivered by caesarean section due to congenital brain tumour and hydrocephalus. His Apgar scores were 5/7 and birthweight was 2700 g (his twin weighed 1200 g). On the prenatal ultrasonographic examination at the 23th week, an intracranial mass and ventriculomegaly were observed in one of the twins. At the same week, fetal MRI showed an irregularly contoured mass measuring 27 × 23 mm which caused compression to the third and fourth ventricles on the midline, and dilatation in both lateral ventricles and third ventricle. The mass progressed rapidly (87 × 70 mm) at the 26th week. Macrocephaly (50.5 cm,>95p), prominent cranial vasculature, widening of sutures and appearance of sunset sign in the eyes and low set ears were observed on physical examination. The other system examinations were normal. Haemoglobin was 7.9 g/dL. Cranial tomography showed intracranial calcifications, the mass with hypodense fat densities (9 × 8 cm), hydrocephalus and significant thinning of brain parenchyma. Cranial MRI revealed a large mass measuring 89x95 × 95 mm with haemorrhagic areas and cystic structures, hydrocephalus, an appearance consistent with hydranencephaly. When he was 3 day old, the patient, operated with the preliminary diagnosis of immature teratoma after the consent of the family, died during operation. Histopathology was reported as immature teratoma.

Conclusion Even if immature teratoma was diagnosed prenatally, the prognosis of this disease is quite poor, therefore, multidisciplinary team approach including neonatologist, neurosurgeon and also family members should be necessary for the management.