Extraventricular neurocytoma of the sellar region

Extra-ventricular neurocytoma (EVN) is rare, mainly described within the cerebral hemispheres or spinal cord. We report a case of sellar neurocytoma presenting with chiasmal compression.

A 50-year-old woman presented with decreasing vision and a bitemporal field deficit. CT and MRI demonstrated an enhancing invasive sellar lesion extending into the sphenoid sinus and left cavernous sinus, with speckled calcification and compression of the optic chiasm. Pituitary function was normal apart from a mildly elevated prolactin level consistent with stalk effect.

Endoscopic trans-sphenoidal resection of the lesion was performed revealing a firm, vascular tumour. Some residual tumour was left within the left cavernous sinus. Histology revealed a neurocytic tumour with nests, islands and strands of neuropil. Diffuse synaptophysin, chromogranin, neurofilament protein and CD56 positivity was seen. A histological diagnosis of EVN, WHO grade II was made and adjuvant radiotherapy was given for the residual tumour.

This is only the second case of neurocytoma of the sella reported. It should be considered in the differential diagnoses of sellar lesions that appear radiologically atypical for pituitary adenomas.