Subependymal giant cell astrocytoma

Other Names: SEGA A benign (not cancer), slow-growing tumor that usually forms in the walls of fluid-filled spaces in the brain. The tumors are made up of large, star-shaped cells called astrocytes. Subependymal giant cell astrocytomas are common in patients with tuberous sclerosis (an inherited disorder in which benign tumors form in the brain and other parts of the body). Also called SEGA.

Signs and symptoms

Individuals with this type of tumor may have no symptoms if cerebrospinal fluid (CSF) flow remains open. Obstruction of CSF flow will result in the symptoms associated with increased CSF pressure: nausea, vomiting, headache (often positional), lethargy, blurry or double vision, new or worsened seizures, and personality change.

Diagnosis

Photograph of a brain section containing a subependymal giant cell astrocytoma

MRI of brain with sub-ependymal giant cell astrocytoma

Diagnosis is made by imaging with a contrast-enhanced MRI or CT scan of the brain. It is recommended that children with TSC be screened for SEGA with neuroimaging every 1–3 years.

Treatment

Pharmacotherapy

Two related drugs have been shown to shrink or stabilize subependymal giant cell tumors: rapamycin and everolimus. These both belong to the mTOR inhibitor class of immunosuppressants, and are both contraindicated in patients with severe infections.

Rapamycin showed efficacy in five cases of SEGA in TSC patients, shrinking their tumor volumes by an average of 65%. However, after the drug was stopped, the tumors regrew.

Everolimus, which has a similar structure as rapamycin, but with slightly increased bioavailability and shorter half-life, was studied in 28 patients with SEGA. There was a significant reduction in SEGA size in 75% of the patients, and a mild improvement in their seizures.

Surgery

A NIH Consensus Conference report in 1999 recommends that any SEGA that is growing or causing symptoms should be surgically removed. Tumors are also removed in cases where a patient is suffering from a high seizure burden. If a tumor is rapidly growing or causing symptoms of hydrocephalus, deferring surgery may lead to vision loss, need for ventricular shunt, and ultimately death. Total removal of the tumor is curative.

Surgery to remove intraventricular tumors also carries risks of complications or death. Potential complications include transient memory impairment, hemiparesis, infection, chronic ventriculoperitoneal shunt placement, stroke, and death.

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition.

• Everolimus (Brand name: Afinitor)approved for the adjunctive treatment of adult and pediatric patients age 2 years and older with tuberous sclerosis complex (TSC)-associated partial-onset seizures. April 2012 approved for the treatment of adults with renal angiomyolipoma and tuberous sclerosis complex (TSC) not requiring immediate surgery. October 2010 approved for the treatment of patients with subependymal giant cell astrocytoma (SEGA) associated with tuberous sclerosis who require therapeutic intervention but are not candidates for curative surgical resection.

Prognosis

After complete surgical removal, a SEGA tumor does not grow back. They do not metastasize to other parts of the body. However, the patient is still at risk for, and often develops, new tumors arising from subependymal nodules elsewhere in the ventricular system.

NIH genetic and rare disease info

• NIH info on Subependymal giant cell astrocytoma

Subependymal giant cell astrocytoma is a rare disease.

Subependymal giant cell astrocytoma Resources
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