Subependymal Giant Cell Astrocytoma in an Adult without Tuberous Sclerosis: Systematic Review and Illustrative Case Example.

 Subependymal giant cell astrocytoma (SEGA) is a rare neoplasm arising from subependymal tissue. Predominantly associated with the tuberous sclerosis complex (TSC), SEGA may present with a range of diverse symptoms, most commonly seizures or neurocutaneous features of TSC. We present a novel case of sporadic SEGA in a 59-year-old woman who presented with acute intraparenchymal hemorrhage (IPH).  Systematic literature review and illustrative case example.  A 59-year-old woman presented with a headache decreased level of consciousness, and acute IPH involving the anterior septum pellucidum and right medial caudate head. MRI was concerning for an underlying neoplasm, which grew slowly on follow-up imaging, prompting microsurgical resection. A gross total resection was achieved, and postoperative pathology confirmed SEGA (WHO grade I) without mutation. She remained disease-free and neurologically intact at 1-year follow-up. A systematic review identified seven publications that revealed pathologically confirmed SEGA in nine adult patients without TSC. Headache, papilledema, and visual disturbances were the most common presenting symptoms. Treatment protocols included microsurgical resection versus biopsy followed by radiographic surveillance, and the overall rate of symptom-free survival was at least 80% as of the last follow-up.  We report the tenth case of sporadic SEGA in an adult patient without TSC, as well as an associated systematic review of this rare neoplastic entity. Further study is required to identify risk factors for the development of sporadic SEGA, as well as potential avenues for the management of this disease that may depart from the standard protocol in pediatric TSC patients.