MICROSCOPIC DESCRIPTION:
The sections show a variably cellular tumour composed of a mixture of oligodendroglial and astrocytic cells and with intermingled enlarged and atypical ganglion cells. Scattered bi-nucleate ganglion cells are identified. The oligodendroglial and astrocytic tumour cells show mild nuclear pleomorphism. Scattered thick-walled blood vesels are identified but there is no evidence of endothelial cell hyperplasia. No mitotic figures are identified and there is no necrosis.
IMMUNOHISTOCHEMISTRY:
- GFAP positive in astrocytic cells
- NeuN positive in neuronal cells
- Nogo A positive in oligodendroglial cells
- IDH-1 R132H mutated
- MGMT negative
- p53 positive in astrocytic cells
- p16 positive
- Synaptophysin positive in neuronal cells
- Topoisomerase labelling index: Approximately 3%.
- BRAF V600E is negative
DIAGNOSIS: Ganglioglioma (WHO Grade I)
The glial component of this ganglioglioma is a mixture of oligodendroglial and astrocytic components and is IDH-1 R132H mutated.