A fifty-three-year-old woman with no significant medical history was admitted due to sudden decreased level of consciousness preceded by headache and vomit. Her Glasgow Coma Scale Score was 5, the patient offered motor response in the extension prone position and right mydriasis. We proceeded with airway isolation. The cranial computed tomography (CT) scan conducted showed an extensive right acute subdural hematoma with a 9mm midline shift (Fig. 1) and no associated subarachnoid hemorrhage. Since the patient had not sustained any traumas, the CT scan was followed by a CTA that confirmed the presence of one 10×6×5mm oval-shaped aneurysm independent from the bifurcation of the right middle cerebral artery responsible for the bleeding in an atypical location such as the subdural space (Fig. 2). We proceeded with the urgent evacuation of the subdural hematoma and the direct clipping of the aneurysm with a favorable clinical course.

Figure 1.

Cranial CT scan (axial slice). Right hemispheric extra-axial hyperdense collection consistent with an extensive acute subdural hematoma with significant mass effect.

Figure 2.

Cranial CTA. Aneurysmal lesion dependent on the bifurcation of the right middle cerebral artery (arrowhead).