The dural sinus malformation (DSM) are rare congenital vascular anomalies with variable anatomic features, clinical conditions, and outcomes. There are two forms of disease: a lateral subtype, affecting the jugular bulb with associated high flow arteriovenous fistula; and a midline subtype, called torcular DSM. The torcular subtype is more common and characterized by a giant dural sinus lake involving the confluens sinuum (torcular Herophili). We present a case of a 28-year-old woman with an ultrasound at 32 weeks’ gestation showing a fetal intracranial thrombosed lesion, measuring 6x4 cm. An elective c-section was performed at 38 weeks’ gestation, and a male neonate was born. He remained asymptomatic, and a brain MRI performed 9 days later showed a thrombosed midline mass due to a torcular DSM. The outcome with conservative treatment was favorable, and further development was unremarkable. The 2-year follow-up imaging demonstrated spontaneous involution of the clot.
The torcular DSM is frequently diagnosed prenatally as an intraluminar lake thrombosis, and differential diagnosis include tumors, subdural collections, vein of Galen aneurysmal malformations, pial malformations, arachnoid and dermoid cysts. A literature review involving 126 patients with torcular DSM found an overall mortality of 22.1%. Torcular DSM seems to have better prognosis than those having dural arteriovenous shunts, and the worst outcomes were associated to brain damage and patent feeders. In addition, antenatal diagnosis and thrombosis of pouch have good prognosis, possibly because the clot may spontaneously obliterate the fistulas. Treatment options must be individualized, and include conservative, embolization, ventriculoperitoneal shunt and endoscopic third ventriculostomy. Although systemic anticoagulation is controverse in infants, it should be considered for patients with sinovenous thrombosis affecting outflow pathways, especially those aggravated by venous congestion. Intervention is recommended for grade III patients because they progress to grade IV, and endovascular treatment is the gold standard therapy due to the risk of fatal intraoperative exsanguination. Whenever possible, embolization should be prioritized over hydrocephalus treatment because it may avoid ventriculoperitoneal shunt. Close follow-up imaging is recommended to detect any changes, with lesion reduction indicating favorable outcome.