Clinical Presentation

A teenager who was involved in a high-speed motor vehicle collision.

Axial noncontrast computed tomography (CT) image demonstrates a biconvex fluid collection along the left frontal lobe (arrow) exerting a considerable mass effect on the adjacent brain. The fact that the rim is bright but the central portion is isodense to brain suggests two distinct episodes of bleeding.

Differential Diagnosis

• Epidural hematoma: A lesion with a biconvex shape in the setting of recent head trauma is classic for epidural hematoma.