ABSTRACT
BACKGROUND: Dural sinus malformations are rare congenital forms of dural arteriovenous shunt. Our goal is to describe prenatal ultrasonography and magnetic resonance imaging (MRI) findings of a thrombosed midline dural venous malformation. CASE: Second-trimester fetal ultrasonography and MRI demonstrated a large T2-hypointense mass centered at the level of the torcular Herophili consistent with complete thrombosis of a dural sinus malformation. A follow-up third-trimester MRI showed decreased thrombus size and no parenchymal injury. A neurologically intact newborn was delivered. CONCLUSION: Dural sinus malformations can lead to fetal intracranial thrombosis. Prenatal imaging is useful to establish the diagnosis of dural sinus malformations and to plan perinatal management and treatment options.