The sections from all the specimens show features of moderately cellular glial tumour with similar appearances. In some parts, increased numbers of dysmorphic neurones are seen. They seem to aggregate with uneven distribution. They have enlarged nuclei, prominent nucleoli and abnormally clumped Nissl substance. They stain with B-tubulin, p16, p53 and focally with synaptophysin and Neu-N. They are GFAP, IDH-1 and MGMT negative.
Elsewhere, there are scattered bipolar astrocytes, which show focal fascicular arrangement. The tumour cells have elongated and hyperchromatic nuclei. There are some Rosenthal fibres and many eosinophilic granular bodies in the background. Perivascular lymphocytes, along with clumps of calcification are noted. No mitoses are seen. No microvascular proliferation or necrosis is present. The features are those of ganglioglioma with the glial component being pilocytic astrocytoma. The topoisomerase index is less than 1%.
DIAGNOSIS:
Ganglioglioma (WHO Grade I) with the glial component being pilocytic astrocytoma.