KIAA1549 and pilocytic astrocytoma: The KIAA1549::BRAF fusion mainly occurs in pilocytic astrocytoma (70–80%), but it has also been reported in pilomyxoid astrocytoma (PMA) and ganglioglioma patients.10 and up to 60% of diffuse leptomeningeal glioneuronal tumor (DLGNT) patients with subtentorial and spinal tumor localization also exhibit KIAA1549::BRAF fusion.11 Molecular diagnosis is established through analysis of CNS tissue biopsies.