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.