The Clinicopathological Features of the Solitary Subependymal Giant Cell Astrocytoma: A Systematic Review.

Subependymal giant cell astrocytoma (SEGA), a circumscribed grade I glioma, is typically associated with tuberous sclerosis complex (TSC). However, "solitary SEGA" has been described. We performed a systematic review of available case reports and case series of solitary SEGA. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was used with the following MeSH terms: "Subependymal giant cell astrocytoma," "Sporadic," "Absence," "Non-associated," "Solitary," and "Tuberous Sclerosis." Data sources included PubMed, Google Scholar, Web of Science, and Cochrane from 1979 to June 29, 2023. Of the 546 studies, 20 met the inclusion criteria. Fifty-nine cases were analyzed. The mean age was 19 years (range 4-75), with 29 women (49.1%). Tumor ranged in size from 0.8 to 5.8 cm. Headache was the most frequent initial symptom (75.6%). The lateral ventricles near the foramen of Monro were the most common location (66.10%). Tumors expressed neuroglial (n = 19) or only glial (n = 20) markers. In nine of 59 cases, genetic studies ruled out germinal TSC1/2 mutations; in 13 cases (22.03%), somatic mutations in those genes were identified. "Solitary SEGAs" included tumors with neuroglial profile and classic morphological pattern, and tumors with only glial markers. It is necessary to confirm in SEGA-like tumors, the dual nature with at least glial fibrillary acidic protein (GFAP), neurofilaments, and synaptophysin antibodies. Screening for TSC1/2 mutations, and probably of the NF type 1 gene, is recommended for both germline and somatic mutations. Long-term clinical follow-up is necessary to analyze biological behavior and compare it with genetic and molecular profiles.