The patient went on to have surgery.

Histology

MICROSCOPIC DESCRIPTION: The sections show a moderately cellular tumor. It forms elongated trabeculae-like structures. These are lined by cells with round to slightly ovoid nuclei and small nucleoli. No perinuclear haloes are seen. There is myxoid material in the background. Occasional mature 'floating' neurons are seen within the lesion. Immature neurocytic cells are not identified. No mitoses are noted. There is no microvascular proliferation or necrosis.

The lesional cells are GFAP, Nogo-A and ATRX positive, indicating glial in differentiation. The topoisomerase index is 1%. Synaptophysin stains background neuropil. NeuN and B-tubulin are negative in these cells. IDH-1 and BRAF are also negative.

FINAL DIAGNOSIS: Dysembryoplastic neuroepithelial tumor (WHO Grade I).