Extraneural Metastasis in Oligodendroglioma: A Comprehensive Review and Outcome Analysis of 90 Cases

Extraneural metastasis in oligodendroglioma is a rare and poorly characterized event. We report a case whereby liver and bone metastasis occurred 19 years after diagnosis. Next generation sequencing on brain and liver oligodendroglioma showed several common mutations and a few unique ones to each organ. We identified a total of 90 similar cases and analyzed them through univariate and multivariate regression analysis to assess the impact of relevant clinical variables on overall survival, post‐metastasis survival, and extraneural metastasis latency. These analyses highlighted the role of 1p19q codeletion in prolonging overall survival and delaying extraneural metastasis onset but interestingly without impacting post‐metastasis survival. Aggressive treatment before metastasis was associated with shorter post‐metastasis survival. Other clinical factors showed limited impact. To our knowledge, this is the only reported case with next‐generation sequencing data on the primary, recurrent, and metastatic oligodendroglioma tumors, providing rare molecular insights into disease evolution. Our study also represents the largest collection of oligodendroglioma extraneural metastasis cases to date, and the only one to include detailed analysis of clinical variables and their impact on survival and metastasis.