We report a case of neonatal dural sinus malformation already visible on antenatal ultrasound. This is a rare disease entity in infants and children. Clinical diagnosis was made by demonstrating a cranial murmur on auscultation; macrocrania and signs of progressive cardiac failure. Imaging studies as cerebral ultrasound, postnatal MRI scan and MR angiography demonstrated a large dural sinus malformation originating from the sagittal sinus with extensive arteriovenous fistulae. Due to the extent of the lesion, the existing ischemic brain damage and involvement of the torcular, no therapeutic options were available and the child died of irreversible cardiac failure. The diagnosis was confirmed with autopsy. We discuss the clinical presentation, imaging and neuropathological results and relate our findings to embryological data and the existing literature.