The hallmark of TSC is the involvement of the brain. This occurs in 95% of affected individuals. The findings in the brain usually take the form of cortical tubers, subepedymal nodules and subependymal giant cell astrocytomas (SEGA).
The name Tuberous Sclerosis comes from cortical tubers, which were first named in 1880 by Bourneville. Tubers are made up of a collection of abnormally sized neurons and their supporting cells (glia). They are most commonly found in the cerebral cortex.The number, size and location of the tubers vary tremendously among patients with TSC. Nowadays, a brain MRI is the most common way of identifying these tubers (see MRI).
Subependymal nodules: These lesions are found along the wall of lateral ventricles in the brain. In the past, they were referred to as "candle guttering" to convey the appearance similar to drippings of wax from a candle. These lesions do not cause any problems. However, in 5-10% of the cases, these benign lesions can degenerate into subependymal giant cell astrocytomas (SEGA). SEGAs can grow and block the circulation of CSF (cerebrospinal fluid) around the brain and cause hydrocephalus. Hydrocephalus leads to a swelling of the brain and requires immediate neurosurgical intervention.