Endocrine Abstracts

Case history: A 50-year-old lady presented with blurred vision in her left eye. She was clinically eupituitary. Visual field testing confirmed a bitemporal field deficit. MRI pituitary showed a pituitary macroadenoma occupying part of the sphenoid fossa and causing significant optic chiasmal compression. The lesion was extending across the left carotid loop, with a part of the lesion extending and compressing the medial aspect of the left temporal lobe. She was found to be hyponatremic and investigations confirmed SIADH. Her prolactin level was elevated at 980 mU/L but the rest of the pituitary function tests were normal. She underwent endoscopic transphenoidal subtotal resection of the pituitary lesion and was commenced on hydrocortisone post-operatively. Histology revealed a WHO grade II extraventricular neurocytoma. Ki-67 index was low. The neurocytic nature of the lesion was confirmed by immunohistochemistry. In view of the subtotal resection and the histology, she was referred for radiotherapy at 4 months. Post-operative glucagon test revealed a peak cortisol of 450 nmol/l and she was weaned off the hydrocortisone. The other pituitary hormones were normal. Post-operative visual field testing revealed a right superior temporal defect and persistent left temporal hemianopia. MRI 8 months post-radiotherapy has revealed a significant tumour residuum and she remains under close follow-up. Discussion: Neurocytomas are rare WHO grade II neuronal tumours with an incidence of 0.1–0.5% ¹ commonly found in the ventricles. Extra ventricular neurocytomas are uncommon and are seen in the cerebral hemishperes. Sellar and suprasellar neurocytomas are very rare with very few cases reported in the literature. Surgery remains the mainstay of therapy. Radiotherapy should be considered early especially in cases of atypical neurocytomas (high ki-67 index or atypical histology), as they have a higher risk of recurrence¹. References: 1. A Hallock et al. Neurocytomas: Long term experience of a single institution. 2011. Neuro-oncology 13(9): 943–949.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.