10214-COT-24 A RARE CLINICAL CASE OF LUMBAR METASTASIS FROM GLIOSARCOMA

Abstract

Abstract Gliosarcoma (GS) is a variant of glioblastoma (GBM) and has been shown to be prone to extracranial metastasis. We report a rare case of lumbar metastasis of Gliosarcoma (GS) based on histopathological findings.37-year-old male.He underwent emergency surgery for a left frontal subcortical hemorrhage. Pathological diagnosis confirmed GS. Postoperatively, the patient underwent conventional radiation chemotherapy. Later, in conjunction with cranioplasty, the remaining lesion was additionally excised and maintenance therapy was administered for 9 months. Subsequently, a follow-up MRI revealed an intracranial disseminated lesion, although the primary site was not affected. At the same time, he had difficulty moving due to back pain, and MRI revealed extracranial metastases in the second lumbar vertebra and retroperitoneum. Lumbar biopsy confirmed the diagnosis of metastasis. Pathological findings at the initial surgery showed that the tumor consisted of GS and gemistocyte-like components, and immunostaining and genetic findings showed IDH wild type GBM. Additional tissue samples showed predominantly gemistocyte-like components and no GS component, and the genetic profile was similar.Lumbar biopsies showed predominantly GS and no gemistocyte-like components. MGMT methylation changed from methylation-negative to positive and then negative by immunostaining and MS-PCR. In a previous report, Feldheim et al. performed a meta-analysis of MGMT methylation changes in relapsing GBM and reported increased methylation after relapse. In addition, Jimenez et al. quantitatively analyzed MGMT methylation in recurrent GBM by pyrosequencing and found an increased rate of methylation in about half of the cases. These reports indicate that MGMT methylation is altered following therapeutic intervention. In the present case, it was hypothesized that an intracranial lesion that was initially unmethylated was methylated by the intervention, but an unmethylated, treatment-resistant GS component metastasized to the extracranial space. The clinical course of this case was a rare example of evidence of a change in MGMT methylation due to therapeutic intervention.