To report two high-grade glioma (HGG) cases with extracranial metastases (EXM) with pathological review and next-generation sequencing (NGS) data.

EXM are rare events for HGG. In a review of 116 gliomas with EXM, glioblastomas were the most common, while oligodendrogliomas were the least common. HGG with EXM have poor prognoses with overall survivals less than six months.

Case reports.

A 35-year-old woman presented with headaches, blurry vision, and seizures. She was diagnosed with anaplastic oligodendroglioma with 1p/19q codeletion after craniotomy but received no adjuvant therapy at our institution. Two years later, she presented with tumor progression and underwent another craniotomy. She received radiotherapy, but later experienced pancytopenia. A restaging scan showed FDG uptake in the bilateral breast and bone marrow. Bone marrow aspiration and biopsy confirmed EXM from oligodendroglioma. The patient expired a few months later.

A 57-year-old man presented with headaches and seizures. He was diagnosed with glioblastoma, IDH-wildtype, MGMT unmethylated after craniotomy. Pathology showed evidence of subpial spread and leptomeningeal involvement. He received standard chemoradiation and adjuvant temozolomide (eight cycles). One year later, he experienced low back pain. MRIs demonstrated increased enhancements along his surgical cavity and at L2 region. Pathology from 2nd craniotomy revealed recurrent glioblastoma. Subsequently, L2 needle biopsy revealed EXM. A restaging scan showed FDG uptake in the right temporal lobe, L2 vertebral body, and right ilium. Salvage treatment included bevacizumab, temozolomide and irinotecan chemotherapies, tumor-treating fields, spinal fusion and vertebroplasty, and spinal radiation. He eventually transitioned to hospice care and expired 20.8 months after his diagnosis.

Timely identification and implementation of interventions for tumor progression and EXM can contribute to improved survivals. Further investigations into EXM mechanisms are imperative to identify prognostic biomarkers and potential therapeutic options that can improve patient outcomes. Comprehensive NGS results will be presented at the meeting.