Pilocytic astrocytoma of the brainstem

Abstract

Aim: To describe a case of pilocytic astrocytoma arising in the medulla, which presented as a sudden- onset esotropia. Method: A case is documented with history, neuro­logical signs, orthoptic findings and management. Pilocytic astrocytoma is discussed in relation to the literature. Results: A small esotropia in a healthy 2-year-old, presenting to a vision screening clinic, was the sole initial sign of a brainstem pilocytic astrocytoma. There was subsequent diagnosis of a mild VIth nerve palsy and development of other neurological signs including gaze-evoked nystagmus and ataxia. Conclusion: Pilocytic astrocytoma is a neuroepithelial tumour of the central nervous system, of low grade, occurring mainly in children and young adults and most commonly in the cerebellum. Pilocytic astro­cytoma of the brainstem is much less common and carries a worse prognosis owing to the difficulty of achieving complete surgical resection. This is a rare condition, but orthoptists must remain aware that they may be the first point of referral in such cases and recognise signs indicative of urgent investigation.