Definition:

Subependymal giant cell astrocytoma (SEGA) is the most common central nervous system tumor in patients with tuberous sclerosis complex (TSC). Although these lesions are generally benign and non-infiltrative, they commonly arise in the region of the foramen of Monro, where they can cause obstructive hydrocephalus and sudden death. TSC is an autosomal dominant genetic disorder caused by inactivating mutations in either the TSC1 or TSC2 genes. These mutations lead to constitutive upregulation of the mammalian target of rapamycin (mTOR) pathway, which affects many cellular processes involved in tumor growth. Clinical studies have demonstrated that mTOR inhibitors can induce regression of SEGA in patients with TSC, providing a viable alternative to surgical removal.