Purpose There are several hereditary disorders that are well known to be associated with arteriovenous malformations (AVMs) involving the central nervous system including Sturge-Weber, Klippel-Trenaunay-Weber, and Parkes-Weber syndromes as well as hereditary haemorrhagic telangiectasia and hereditary neurocutaneous angiomatosis. Furthermore, familial incidence of AVMs in the absence of congenital hereditary disorders also has been reported. Herein, we describe the occurrence of the giant torcular herophili (TH) dural arteriovenous fistula (AVF) in two pediatric cousins treated with endovascular embolization.

Case report Case 1: Five-month-old male with the chief complaint of poor head control, right head tilt, and increasing head circumference with full and pulsatile fontanelle presented and following imaging studies revealing marked venous dilation adjacent to the vein of Galen he underwent multiple sessions of embolization and radiation therapy without significant improvement. Ten months later the patient presented to our center with significant clinical deterioration with developing seizure and apnea requiring immediate intubation. Case 2: Second case was the third-degree relative (paternal cousin) of case 1. A 20-day-old female was admitted for evaluation of failure to thrive, dysphagia, and enlarged head circumference with bulging fontanelles. Pregnancy history was remarkable for intrauterine diagnosis of an intracranial mass superior to the posterior fossa which was identified on 20-week gestation ultrasound. Amniocentesis with chromosomes and SNP array examinations were reported normal. Mother denied smoking and drinking alcohol during pregnancy and family history was negative for haematological disorders, cardiovascular events and stroke prior to age 50, stroke or frequent miscarriages.

Image findings Case 1: Immediate cerebral angiography was performed and venography of the TH demonstrated the filling of the large cavity within the mostly thrombosed TH with retrograde drainage into the superior sagittal sinus (SSS) and subsequently into the deep cerebral vein via a second channel. Embolization of the TH and the distal thirds of the SSS were performed utilising multiple hydro coils followed by pushable fibre coils and N-butyl cyanoacrylate in multiple sessions. Although complete obliteration of the shunts was achieved, the sequels of the prolonged drainage disturbance remained due to the late diagnosis. Case 2: Fetal MR imaging (MRI) revealed a midline mass in the region of the TH with signal characteristics of blood or blood products that was thought to be consistent with dural sinus thrombosis (Figure). Following presentation, cerebral angiography demonstrated a significant AV shunting from multiple meningeal vessels including bilateral occipital, middle meningeal arteries, and posterior meningeal arteries into a massively enlarged TH either directly or through intermediate dural veins. Subtle opacification of the outflow into the right sigmoid sinus and internal jugular vein and normal venous drainage from the SSS to the TH also was observed. Additionally, there was evidence of venous collateral pathways including the petrygoid venous plexuses due to the venous hypertension. Endovascular embolization was performed in multiple sessions using Onyx resulting in obliteration of the shunt with long-term favorable angiographic and clinical outcome.

Summary To the best of our knowledge, our case series represents the only reported familial incidence congenital DSMs involving TH in children.

Disclosures A. Honarmand: None. M. Hurley: None. V. Daruwalla: None. S. Ansari: None. A. Shaibani: None.