A 63 year old female was referred to ophthalmology in December 2007 with a 10 day history of redness, itching and watering of her left eye: the eye had congestion, chemosis and mild proptosis, and ocular movements were mildly restricted. There was no reduction in visual acuity. MRI in January reported no intraocular or intraorbital lesion, and an inflammatory cause was sought - possibly thyroid eye disease. She did not improve on pressure lowering treatments but had some improvement with steroids, which were continued in high dose. TSH was normal with negative thyroid peroxidase antibodies. In April 2008 she returned with a tense left orbit, engorged conjunctiva and episcleral vessels. Eye movements were severely limited. A further MRI was reported as showing enlarged, high signal recti muscles in T2-phase in the left eye, with superior orbital vein distension. In May the patient was admitted for intravenous methylprednisolone and endocrine review, to discuss whether there was asymmetric thyroid eye disease. New onset diabetes was also found. TSH receptor antibodies were negative, and an urgent second opinion was sought. Her scans were reviewed at another centre, and a meningioma at the left petrous apex extending into the cavernous sinus identified. Stereotactic radiosurgery was performed.
Discussion: Timely endocrinology involvement could have led to rejection of thyroid eye disease as the cause for proptosis, with earlier correct diagnosis and avoidance of steroid-induced diabetes. Meningiomas of the petrous apex can invade medially into the cavernous sinus and are isointense on non-enhanced T1-phase MRI. Invasion into the cavernous sinus, causing reduction in venous outflow caused the symptoms in this case. Cavernous sinus syndrome can be caused by infective, inflammatory, vascular and neoplastic lesions. It is an important differential when considering unilateral and bilateral proptosis and conjunctival injection when thyroid antibodies are negative.
Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.