Extraneural metastases of glioblastoma: A case report and literature review

Background: Glioblastoma (isocitrate dehydrogenase [IDH]-wildtype, WHO Grade 4) is known to have a high recurrence rate with poor management of morbidity and mortality. Metastatic spread of glioblastomas is rare with extraneural osseous spread having been reported in under 100 cases. In this report, a case of glioblastoma with widespread extraneural metastatic lesions, including distal extremities, is presented. Case Description: A 70-year-old female presented with progressive word-finding difficulty and confusion. Brain magnetic resonance imaging (MRI) revealed a 5 × 7 cm left temporal solid and cystic mass with heterogenous contrast enhancement and significant surrounding edema. She underwent near-total tumor resection, and the pathological diagnosis was glioblastoma, (IDH-wildtype, WHO grade 4), with sarcomatous and primitive neuronal components. She received radiation therapy and temozolomide over 4 months. At 5 months postoperative, she presented with new bilateral lower extremity weakness and left facial droop. MRI and positron emission tomography scans revealed local recurrence and metastatic lesions to vertebrae, extremities, and lymph nodes. Conclusion: Previous research into rare glioblastoma bone metastases supports the theories of spread through hematogenous routes, surgical disruption, glymphatic system, and potential genetic susceptibility. However, no literature to date can adequately explain the distal limb metastases presented in this case, which shows the necessity for further understanding of this pathology.