FINAL DIAGNOSIS: Anaplastic oligodendroglioma - WHO Grade III.
Anaplastic oligodendroglioma is a WHO grade III diffuse infiltrating glioma that has histological features of anaplasia, and molecular markers consistent with an oligodendroglioma (1p19q co-deletion and IDH mutation) as per the current (2016) WHO classification of CNS tumors 1. They make up 20-50% of all oligodendrogliomas.
As the molecular status is unavailable then the diagnosis relies on histology alone and is given the designation oligodendroglioma NOS (grade 3).