Subependymal giant cell astrocytoma (SEGA) is a benign (noncancerous), slow-growing tumor that forms in the walls of the ventricles, the fluid-filled spaces in the brain. SEGA is common in people with tuberous sclerosis complex (TSC), a rare genetic disease that causes benign tumor growth throughout the body. Because SEGA tumors are found in the ventricles, they can block the flow of cerebrospinal fluid (CSF) and cause neurological symptoms.
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What Is Subependymal Giant Cell Astrocytoma (SEGA)?
Subependymal giant cell astrocytoma (SEGA) is a benign (noncancerous), slow-growing tumor that forms in the walls of the fluid-filled spaces called ventricles in the brain. SEGA is common in people with tuberous sclerosis complex (TSC), a rare genetic disease that causes benign tumor growth throughout the body. Because SEGA tumors are found in the ventricles, they can block the flow of cerebrospinal fluid (CSF) and cause neurological symptoms.
How common is SEGA?
SEGA is a rare condition that occurs in 5% to 20% of people with TSC.
What is the syndrome associated with SEGA?
SEGA occurs mostly in people who have tuberous sclerosis complex (TSC).
What causes SEGA?
SEGA is strongly associated with TSC, a rare genetic condition affecting approximately 1 in 6,000 people. TSC is caused by mutations in the TSC1 (hamartin) or TSC2 (tuberin) genes. These mutations hyperactivate the mammalian target of the rapamycin (mTOR) pathway, promoting abnormal cell growth.
SEGA risk factors
A diagnosis of tuberous sclerosis complex (TSC) is the most significant risk factor for developing SEGA.
Complications of SEGA
SEGA may block spinal fluid flow and/or put pressure on surrounding structures, which can cause:
- Balance problems.
- Cognitive decline.
- Headaches.
- Hydrocephalus (a buildup of cerebrospinal fluid in the brain).
- Seizures.
- Vision disturbances.
How can I prevent SEGA?
There is nothing you can do to prevent SEGA, as it is driven by genetic mutations. However, regular monitoring in TSC patients can enable early detection and intervention.
What Are the Signs and Symptoms of Subependymal Giant Cell Astrocytoma?
SEGA tumors may not cause symptoms until they grow large enough to block the flow of CSF or cause pressure in your brain.
As the SEGA tumor grows, symptoms may include:
- Confusion.
- Headaches.
- Nausea or vomiting.
- Personality changes.
- Seizures.
- Speech, vision, or memory problems.
- Weakness or loss of sensation in the arms and/or legs.
When should I see a doctor about my SEGA symptoms?
If you or a loved one experience these symptoms, especially with a known TSC diagnosis, contact a doctor immediately. For severe symptoms (such as intense headaches, vomiting, or seizures), call 911 or go to the emergency department.
How Do You Diagnose Subependymal Giant Cell Astrocytoma?
At UPMC, our neurosurgeons will do an exam to check your vision, reflexes, and other neurological functions.
What to expect during your visit
If your doctor suspects SEGA, they will:
- Ask about your symptoms.
- Perform a physical and neurological exam.
- Order other tests.
- Review your health history and medications.
Tests to diagnose SEGA
Your doctor may order imaging studies, including:
- CT scan — A painless, noninvasive test that uses x-ray technology to capture multiple cross-sectional images of organs, bones, and tissues inside your body.
- Magnetic resonance imaging (MRI) — A safe, noninvasive imaging test that uses a magnetic field and radio waves to pinpoint where the tumor is and help doctors determine the size.
SEGA prognosis
Your prognosis after a SEGA diagnosis depends on the tumor size and location, as well as your age and overall health.
Patients with TSC should undergo brain MRI every one to three years until age 25 to monitor for SEGA development, as recommended by the 2021 International TSC Consensus Group.
How Do You Treat Subependymal Giant Cell Astrocytoma?
UPMC's neurosurgical team may recommend a combination of surgical and nonsurgical approaches to treat SEGA.
Surgery
Surgery is the standard treatment for SEGA.
UPMC's neurosurgical team thoroughly evaluates each patient before surgery. Our team strives to find the least disruptive surgical approach for your brain and critical nerves, ensuring your ability to return to normal functioning after treatment.
Neuroendoport® surgery
Neuroendoport surgery offers a minimally invasive option to treat tumors within the ventricles (fluid spaces) or deep-seated tumors within the substance of the brain. A narrow tube or port allows surgeons to access the SEGA through a tiny incision in your scalp, making it less invasive than traditional brain surgery.
Gamma Knife® stereotactic radiosurgery for SEGA
Gamma Knife® radiosurgery is a painless procedure that uses hundreds of highly focused radiation beams to target tumors and lesions within the brain, with no surgical incision.
Gamma Knife treatment may be an option when parts of your tumor must be left behind after surgery or if your SEGA recurs. Gamma Knife radiosurgery can also enhance the effectiveness of radiation delivered directly to the tumor.
As the nation's leading provider of Gamma Knife procedures, our team has treated more than 19,500 patients with tumors, including SEGAs, as well as vascular malformations, pain, and other neurological issues.
UPMC neurosurgeons may also treat SEGAs with stereotactic radiosurgery using the Cyberknife and other linear accelerator-based systems.
Medication
Your doctor may recommend medical therapy, such as everolimus (mTOR therapy), to slow or stop tumor growth. However, in some people, tumors may continue to grow while on medication or when medication is stopped.
Why Choose UPMC for Subependymal Giant Cell Astrocytoma Care?
When you choose UPMC for SEGA care, you will receive:
- Access to world-class neurosurgery expertise — Our world-renowned experts treat the full spectrum of neurosurgical conditions using the latest diagnostic and treatment techniques.
- A full range of treatment options — We offer nonsurgical care and noninvasive, minimally invasive, and traditional open surgical procedures. This allows us to effectively treat all types of disorders while reducing your risk of complications.
- Multidisciplinary care — We partner with neurologists, rehabilitation specialists, and other medical experts to provide complete care that optimizes your recovery and quality of life.
