Neurohypophyseal pilocytic astrocytoma invading the skull base

We describe the clinical presentation, neuroradiological and histological findings of an unusual case of pilocytic astrocytoma of the neurohypophysis, and discuss the related surgical and prognostic issues of this neoplasm which invaded the skull base and the sphenoid sinus. Only four histologically proven cases of such a tumour have been reported in the English literature, and the pathological features and behaviour of this neoplasm still await definition.