The patient went on to have an endoscopic biopsy.
Histology
MICROSCOPIC DESCRIPTION:
The sections show features of a moderately cellular glial tumour. Scattered bipolar astrocytes are seen, which show focal somewhat fascicular arrangement. The tumour cells have elongated and hyperchromatic nuclei. No Rosenthal fibres or eosinophilic granular bodies are seen in the background. No mitoses are present. No microvascular proliferation or necrosis is identified. The features are those of pilocytic astrocytoma. The topoisomerase index is less than 1%. IDH-1 immunostain is negative.
DIAGNOSIS: Hypothalamic tumour: Pilocytic astrocytoma (WHO Grade I).
Histology courtesy of Dr Alpha Tsui, Royal Melbourne Hospital.