Spontaneous Chronic Subdural Haematoma Due to Hypoplastic Rostral Superior Sagittal Sinus.

The superior sagittal sinus (SSS) is a midline structure of the superficial cerebral venous system that drains the anterior cerebral hemispheres. Hypoplasia of the rostral SSS is a known variant, although associated complications are rare. A woman in her 30s presented for evaluation of a symptomatic left-sided acoustic neuroma and was found to have an incidental chronic subdural haematoma (SDH) over the left frontoparietal convexity without trauma or precipitating event. The SDH expanded on serial imaging and the patient eventually underwent left-sided frontoparietal craniotomy for haematoma evacuation. Haematological evaluation was benign, but angiography revealed absence of the anterior half of the SSS. We report the first case of spontaneous SDH in the setting of hypoplastic rostral SSS.