Different outcomes in two cases of Dural Sinus Malformation
Fetal Dural Sinus Malformation (DSM) is a rare condition with massive dilation of dural sinuses due to an arteriovenous shunt. It most frequently involves the confluence sinuum above the cerebellum in the posterior fossa [1,2]. Clinical courses range from intrauterine demise (IUD) to live birth with normal neurological outcome depending on associate factors like sufficient collateral venous drainage, absence of additional structural abnormalities, brain insult, infarction, ventricular hemorrhage and cardiac failure.
We report on two consecutive cases of DSM. In case 1 the diagnosis was made on post mortem pathologic examination after IUD at 21 wksGA. Sonographically the abnormality was misclassified as a brain tumor. In case 2 a mass was spotted during routine scan at 26 wksGA and assessed by Level 2 ultrasound accompanied by fetal MRI and telemedical expert consultation. The posterior fossa mass with a size of 4.5 × 4.9 × 6.5 cm and signs of an intraluminal thrombus was associated with mild ventriculomegaly and downwards-shift of the cerebellum. Both the size of the lesion and secondary features decreased with ongoing pregnancy. Delivery was performed 37+1 wksGA by planned caesarian section. (APGAR 9/10/10). Neonatal intensive care was required for respiratory complications due to borderline preterm delivery. Postnatal cMRI confirmed the diagnosis of thrombosis in the sagittal posterior sinus decreasing in size in comparison to prenatal findings accompanied by hypoplastic transverse and sigmoid sinuses.
Thrombosis of a DSM may lead to secondary intraventricular hemorrhage and hemorrhagic cerebral necrosis which had been the cause of IUD in case 1, where the Sinus confluens showed partial thrombosis. On the contrary, in the absence of severe complications DSM may lead to favorable perinatal outcome not even requiring neurosurgical or minimal-invasive radiologic intervention .
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