Astrocytoma Pleomorphic xanthoastrocytoma 2021-03-06T13:14:42Z Pleomorphic xanthoastrocytomas (PXA) are rare low-grade astrocytomas (WHO Grade II) typically found in the temporal lobe and classically presenting with epilepsy. PXA is an astrocytic neoplasm that most often presents in children or young adults but can also occur in adults. The diagnosis of anaplastic PXA is made based upon tumor histopathologic characteristics and requires increased proliferative activity (mitotic index at least 5 mitoses/10 HPF), which is associated with worse overall survival. In general, anaplastic PXAs acquire features of a more aggressive astrocytic neoplasm that can include increased proliferation, necrosis, microvascular proliferation, loss of pericellular reticulin, and increased infiltrative growth.