Subependymal Giant Cell Astrocytoma
Subependymal giant cell astrocytoma (SEGA) is a benign brain tumor (WHO Grade 1) that is almost exclusively seen in the setting of tuberous sclerosis. It affects 5% to 15% of patients with tuberous sclerosis and is usually diagnosed before the age of 20 yrs. This intraventricular tumor is usually located in the lateral or third ventricle near the foramen of Monro and may cause obstructive hydrocephalus, although most cases are asymptomatic. On MRI scans, it is solid, well-circumscribed, often calcified, and enhances with contrast. Microscopically, it is composed of epithelioid, gemistocyte-like, or spindle cells arranged in sweeping fascicles.