ABSTRACT
The vein of Galen malformation is caused by an abnormal shunting between choroidal arteries and the median prosencephalic vein during embryological development, leading to increased blood flow to the deep cerebral veins, intracranial damage, and systemic repercussions. Idiopathic spontaneous thrombosis of a vein of Galen malformation is rare, and its association with acute sinusitis has not been reported in the literature. We present the case of a girl with a postnatal diagnosis of a vein of Galen malformation at the age of 16 months, with secondary pulmonary hypertension that was adequately controlled with spironolactone. At 3 years old, while expecting elective endovascular treatment, the patient developed spontaneous thrombosis of the vein of Galen malformation, concomitant to an acute sinusitis episode, with complete resolution of the vascular malformation and secondary pulmonary hypertension. The patient continued with normal neurological development over a 5-year follow-up. We discuss the main pathophysiologic mechanisms that can explain spontaneous thrombosis of VOGMs and the patient's outcome. Awareness of different mechanisms that can lead to spontaneous thrombosis can help in the decision-making process and prompt targeted approaches to individual patients with a vein of Galen malformation.