subependymal giant cell astrocytoma
A slow-growing astrocytic tumor associated with tuberous sclerosis complex, characterized by large gemistocytic cells.
Full Definition
Subependymal giant cell astrocytoma (SEGA) is a WHO grade I astrocytic tumor that occurs almost exclusively in patients with tuberous sclerosis complex (TSC). These tumors arise from subependymal nodules near the foramen of Monro and are characterized by large, gemistocytic cells with abundant eosinophilic cytoplasm and often multiple nuclei. The cells may show neuronal differentiation markers and can express both GFAP and neuronal proteins. SEGAs typically grow slowly but can cause obstructive hydrocephalus due to their strategic location. They are associated with mutations in the TSC1 or TSC2 genes affecting the mTOR signaling pathway.
Usage
Usage note: Pathognomonic for tuberous sclerosis complex; mTOR inhibitors may be used as adjuvant therapy.
In Context
- "The subependymal giant cell astrocytoma showed characteristic large gemistocytic cells in a patient with confirmed tuberous sclerosis." — Pediatric neuropathology report
- "SEGA was suspected given the tumor location near the foramen of Monro and the patient's TSC history." — Neurosurgical consultation