Cerebral Sinus Venous Thrombosis Recurrence in a Toddler With Dural Sinus Malformation: A Case for Prolonged Therapeutic Anticoagulation Treatment

Dural sinus malformation (DSM) is characterized by localized sinus ectasia and/or fistulous connections, represent a distinct underlying pathology that significantly increases the risk of cerebral sinus venous thrombosis (CSVT) due to localized flow stasis within the malformed venous structures. We report a previously healthy 2-year-old boy with extensive CSVT involving an ectatic superior sagittal sinus, torcula, bilateral transverse and sigmoid sinuses, and cortical veins. Digital subtraction angiography confirmed a low-flow DSM without arteriovenous shunting. Following treatment with unfractionated heparin and therapeutic rivaroxaban, the thrombus resolved after 6 months, and anticoagulation was reduced to prophylactic dosing. Five months later, after a 1-week interruption of prophylactic anticoagulation, surveillance imaging demonstrated recurrent non-occlusive thrombosis involving the ectatic superior sagittal sinus, torcula, and straight sinus. Therapeutic rivaroxaban was restarted, with subsequent reduction in thrombus burden. This case highlights the persistent thrombotic risk associated with low-flow DSM and suggests that prophylactic anticoagulation may be insufficient in patients with substantial venous ectasia and flow stasis. Serial imaging may help guide anticoagulation intensity and duration, although the optimal long-term anticoagulation strategy remains uncertain.