- 1 in 200,000 births.
- Avascular, supratentorial, hyperechogenic mass in the posterior fossa above the cerebellum, surrounded by a triangular sonolucent area (the dilated venous sinus).
- The incidence of chromosomal abnormalities and genetic syndromes is not increased.
- Detailed ultrasound examination, including neurosonography.
- Fetal brain MRI is necessary to conﬁrm the diagnosis and describe its location and size.
- Ultrasound scans every 4 weeks to monitor the evolution of the lesion.
- Repeat MRI after 6-8 weeks to exclude infarction and hemorrhage of the cerebral parenchyma.
- Standard obstetric care and delivery.
- Normal head size with decreasing thrombus size indicate a favourable prognosis. Postnatally, management is usually non-interventional.
- No increased risk of recurrence.