Hyalinized vessels are commonly seen in pilocytic astrocytomas as depicted in this image. Foci of infarct-like necrosis may be present in 5% to 10% of cases. Recent studies have shown that pilocytic astrocytoma is associated with changes in mitogen-activated protein kinase pathway (MAPK). With whole genome sequencing, activating mutations have been identified in FGFR1 and PTPN11 genes. In addition, BRAF-activating changes have also been seen. Ref: Jones DT, et al. Nat Genet, 2013 Aug;45(8):927-932.