1. The sections show cerebral cortex and white matter. There is a spindle cell proliferation involving the full thickness of cerebral cortex and extending into underlying white matter. This is sharply demarcated from both cortex and white matter. Spindle cells show strong immunostaining for GFAP indicating astrocytic differentiation and have mild nuclear pleomorphism. Small bundles of collagenous material are seen within the astrocytic spindle cell population. Moderate numbers of mature ganglion cells are admixed with and aggregated at the edge of the astrocytic spindle cell component. These show strong nuclear immunostaining for NeuN and perinuclear staining for beta-Tubulin. Several ganglion cells are binucleated. The astrocytic spindle cells also show nuclear immunostaining for p53 and p16 and positive cytoplasmic staining for BRAF V600E, but are negative for IDH-1 R132H. The overall features are of desmoplastic ganglioglioma. The topoisomerase labelling index is approximately 1%.
2. The section shows a glioneuronal lesion with features similar to those seen in specimen 1. In addition, features of focal cortical dysplasia - Taylor Type IIa are seen in adjacent cortex. These changes include loss of normal laminar architecture and the presence of enlarged dysmorphicc neurones. No balloon cells are seen.
- Left temporal lobe lesion: Desmoplastic ganglioglioma (WHO Grade I)
- Perilesional tissue: Desmoplastic ganglioglioma (WHO Grade I) and Focal cortical dysplasia - Taylor Type IIa in adjacent cortex.
Original specimens from 2003 and 2009 have been reviewed. These also show features of desmoplastic ganglioglioma.