EP05.46: Fetal congenital medulloblastoma diagnosed by prenatal ultrasound and MRI

Medulloblastoma represents the most common malignant pediatric brain neoplasm. However, congenital medulloblastomas are extremely rare and mostly diagnosed postnatally. Here the authors report a care of fetal medulloblastoma diagnosed prenatally by ultrasound examinations and MRI. A 35-year-old multiparous woman was undergoing prenatal care at our hospital, but there were no specific findings. On ultrasound performed at 33 + 4 weeks of gestational age, a cerebellar tumour with colour Doppler and mild dilatation of the left ventricle were observed. MRI findings showed that the mass lesion involving the fourth ventricle and cerebellum, causing hydrocephalus with ventricular dilatation, and the differential diagnosis could be posterior fossa tumour, including congenital medulloblastoma or ependymoma. As the size of the cerebellar tumour gradually increased and left ventricular enlargement increased, a Caesarean section was performed at 36+0 weeks of gestation. A male newborn was born with a birthweight of 2420 g, a 1 min Apgar score of 8, and a 5 min Apgar score of 9. After birth, the underwent brain tumour resection, and pathological findings of medulloblastoma were confirmed. With this in mind, if a rapidly growing fetal brain tumour is found during prenatal care, clinicians should perform detailed ultrasound and MRI.