Histology report

The sections show features of a moderately cellular glial tumor. There are scattered neoplastic astrocytes with mildly pleomorphic and elongated nuclei. There is also a proliferation of neoplastic oligodendroglial cells. These cells extend into the cortex with perineuronal satellitosis. The tumor cells have enlarged round nuclei. Perinuclear haloes are inconspicuous. There are scattered spots of basophilic calcification in the cortex. No mitoses are seen. There is no evidence of endothelial cell hyperplasia or necrosis. 

Final diagnosis:

Oligoastrocytoma (NOS) (WHO grade II).

NOTE: This case predates the 2016 WHO classification of CNS tumor revision. As no 1p19q co-deletion status is available a formal diagnosis cannot be reached and the NOS is therefore used (not otherwise specified) - which is recognized in the current classification for cases where molecular information is unavailable. It should also be noted, that under the new classification both an astrocytic and oligodendroglial component needs to be identified, each with its own molecular markers. True oligoastrocytomas are therefore going to be rare, and this case would most likely be classified as either an astrocytoma or an oligodendroglioma. Given extensive calcification, this is likely to be 1p19q co-deleted and most likely would be classified as an oligodendroglioma. Unfortunately, it is not possible to establish this in this historical case, as such one must fall back on the original histological diagnosis.