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Subependymal Giant Cell Astrocytoma (SEGA)

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A subependymal giant cell astrocytoma is a large subependymal nodule (SEN). They are benign and composed of undifferentiated dysfunctional cells, including balloon cells. In rare cases, SEGAs grow large enough to obstruct the flow of cerebrospinal fluid through the lateral ventricles of the brain and may cause hydrocephalus, an enlargement of the skull and pressure on the brain.