The patient went on to have a resection. 

Histology

MICROSCOPIC DESCRIPTION:

1. The sections of temporal neocortex and white matter show a disturbance of cortical lamination with a haphazard arrangement of enlarged dysmorphic neurons and segments in which there is persistence of a columnar arrangement of cortical neurons. No balloon cells are seen. There is no evidence of tumor. The features are of cortical dysplasia ILAE - Type IIIb.

2. The sections show mildly hypercellular parenchyma in which there is admixture of haphazardly arranged ganglion cells, reactive astrocytes and cells with small round hyperchromatic nuclei. These last cells have a vague columnar arrangement. Many ganglion cells are noted within spaces filled with loose myxoid/mucinous material. No mitotic figures are identified and there is no microvascular proliferation and no necrosis. The features are of dysembryoplastic neuroepithelial tumor (DNET). The topoisomerase labeling index is <1%.

DIAGNOSIS:

1. Cortical dysplasia - ILAE Type IIIb;
2. Dysembryoplastic neuroepithelial tumor (DNET).