The patient went on to have surgery.

Histology

MICROSCOPIC DESCRIPTION: All the sections contain tumor which is moderately cellular. The glial cells have elongated, angulated and hyperchromatic nuclei. Some fascicular arrangement is noted. Scattered dysmorphic neurons are seen, intermixed with the glial cells. They are haphazardly arranged. Some are binucleated. They have nucleomegaly. Mitoses are inconspicuous. No microvascular proliferation or necrosis is present.

Occasional eosinophilic granular bodies are noted. There is no oligodendroglial component. The adjacent cortex shows cortical dysplasia with disorganized neurons but no balloon cells (FCD Type IIIb). Some of the tumor cells are GFAP positive and other cells NeuN and synaptophysin positive, indicating both glial and neuronal differentiation. IDH-1 and MGMT are negative.

The topoisomerase index is 1-2%. ATRX shows no loss of staining (non-mutated). The features appear to show a low grade glioneuronal tumor, consistent with a ganglioglioma.

FINAL DIAGNOSIS:

Low grade glioneuronal tumor, consistent with a ganglioglioma (WHO Grade I).