We present the case of a 56 year old Caucasian lady who was referred to the oculoplastic and orbital clinic with right sided slowly progressive non pulsatile proptosis.

The patient presented with a 2 year history of right eye proptosis with no history of trauma or diplopia. She was otherwise fit and well using no regular medications. Her LogMAR vision at presentation was -0.06 (RE) and -0.2 ( LE).

Examination revealed a right afferent pupillary defect and 4mm proptosis. This was associated with an increased vertical palpebral aperture and superior scleral show. Ocular motility of the right eye was reduced in up gaze and adduction with lid lag seen in down gaze. Fundoscopy was unremarkable with no optic disc swelling. Colour vision was normal and visual fields were full.

Routine bloods including thyroid function tests were normal, however thyroid peroxidase auto antibodies were markedly raised. A clinical diagnosis of thyroid eye disease was made.

Routine Neuroimaging was ordered and to our surprise there was no radiographic evidence of thyroid eye disease. Both the MRI scan and subsequently an orbital CT scans revealed an extensive meningioma overlying the sphenoid wing and temporal bone. This was associated with hyperostosis of the right sided orbital bones. The extra ocular muscles were of normal size and there was no sign of orbital fat proliferation.

A diagnosis of spheno-orbital meningioma was made and the patient referred to the neurosurgeons for surgical de-bulking.

Although initial presentation was consistent with thyroid eye disease, neuroimaging revealed a diagnosis of spheno-orbital meningioma, which would have been over looked in the absence of orbital imaging.