Intracranial arachnoid cyst; an unusual cause of epiphora.

Purpose: To describe a case of unilateral intracranial arachnoid cyst in association with enophthalmos and epiphora on the same side.

Methods: Case report.

Results: A young man with symptoms of unilateral epiphora is described. He had a large intracranial arachnoid cyst with an unusually large orbit leading to enophthalmos and symptomatic epiphora on that side. Radiological features of the orbit and associated pneumosinus dilatants are described. We also offer hypotheses to describe the paradoxical occurrence of an expanding intracranial mass and inward growth of the orbit and paranasal sinuses.

Conclusion: A new cause for enophthalmos is described.