A case of solitary subependymal giant cell astrocytoma with histopathological anaplasia and TSC2 gene alteration.

We report a case of subependymal giant cell astrocytoma (SEGA) with anaplastic histological features in a 3-year-old girl. She had no clinical manifestations of tuberous sclerosis complex (TSC) and no relevant family history. A few cases have been reported in which patients with SEGA had no other clinical manifestations of TSC (solitary SEGA). Genetic analysis using a blood sample from the patient showed no germline alterations in TSC1 or TSC2 genes, while the tumor tissue exhibited loss of heterozygosity (LOH) in TSC2. SEGAs are benign, slowly growing tumors that rarely have significant mitotic activity. However, histopathological examination in the present case revealed high mitotic activity and necrosis besides the typical large plump cells arranged in sheets. This may be the first genetically proven case of a solitary SEGA with histopathological anaplastic features. In this report, we reviewed solitary SEGAs and histopathological malignancy in SEGA.