Subependymal giant cell astrocytoma (SEGA)

What it is

Subependymal giant cell astrocytoma (SEGA) is a benign-behaving (WHO grade 1) tumor strongly associated with tuberous sclerosis complex (a genetic condition). It arises near the ventricles of the brain and can block the flow of cerebrospinal fluid. It is treatable with a targeted drug as well as surgery.

Understanding Subependymal giant cell astrocytoma (SEGA)

SEGA occurs almost exclusively in people with tuberous sclerosis complex, a genetic condition that causes tumors in various organs. SEGAs grow near the ventricles, where they can obstruct CSF flow and cause hydrocephalus (fluid buildup), so they are monitored in people with tuberous sclerosis. A distinctive feature is that SEGAs respond to targeted drugs called mTOR inhibitors (such as everolimus), which can shrink the tumor — offering a non-surgical treatment option, particularly useful for tumors that are difficult to remove or are causing problems. Surgery is also an option, especially if the tumor is causing acute obstruction. SEGA illustrates how understanding the underlying biology (the tuberous sclerosis pathway) enables targeted treatment. Understanding SEGA clarifies a benign-behaving tumor of tuberous sclerosis that is often targetable.

Why it matters

Understanding SEGA helps patients and families see a benign-behaving tumor linked to tuberous sclerosis — one that is monitored for CSF blockage and can often be treated with a targeted drug as well as surgery.