Woman presents with worsening diplopia
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A 63-year-old woman with diabetes, high blood pressure, depression and ovarian cysts presented to New England Eye Center for worsening diplopia for a few months.
The diplopia was more noticeable at near than at distance, with newly observed vertical diplopia when she looked up. She was previously established with the strabismus service for a comitant convergence insufficiency-type exotropia, which had been stable. She wore separate distance and near glasses with 4 ΔD of base-in prism for distance and 6 ΔD of base-in prism for near. Ophthalmic history included vision therapy in childhood.
Examination
Examination revealed best corrected visual acuity of 20/20 and 20/25 in the right and left eyes, respectively. Pupillary exam showed anisocoria with a slightly larger right pupil (4.5 mm right eye vs. 4 mm left eye), which was similar in photopic and scotopic conditions. The right pupil was also sluggish and minimally reactive to light. There was no relative afferent pupillary defect. There was mild ptosis of the right upper eyelid. IOP and anterior and posterior segment examinations were within normal limits with no optic nerve edema.
On sensorimotor exam, the right eye was noted to have limited elevation, adduction and depression (Figure 1). The previously noted exotropia had developed significant incomitance with a larger exotropia in left gaze, although it was unchanged in primary gaze at distance. Additionally, a new right hypotropia was noted in upgaze. Stereoacuity at near remained intact at 40 seconds of arc with an intermittent exotropia at near that was unchanged from prior measurements. There was no nystagmus or evidence of internuclear ophthalmoplegia.
Source: Allison Coombs, DO, MS, and Sylvia H. Yoo, MD
What is your diagnosis?
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Worsening diplopia
The differential diagnosis for an incomplete oculomotor nerve (CN III) palsy with pupillary involvement includes compressive lesion, ischemic vasculopathic etiology (microembolic phenomenon), vasculitis, infiltrative disease such as leukemia, meningitis or other cause of intracranial inflammation, demyelinating disease, toxic neuropathy from chemotherapies, trauma and ophthalmoplegic migraine.
Workup
The patient underwent further evaluation with her primary care physician to follow up on diabetes and hypertension control, which were stable. In addition, there was no evidence of active infection or hematologic malignancy.
MRI with and without contrast of the brain and orbits (Figure 2) revealed a broad-based, paraclinoid extra-axial enhancing mass invading the right cavernous sinus with encasement of the right cavernous internal carotid artery. An additional enhancing mass was found at the foramen magnum, causing mass effect.
The diagnosis was cavernous sinus meningioma (CSM) causing incomplete right CN III palsy with pupillary involvement, with an incidental finding of foramen magnum meningioma.
Management
The patient was referred to neurosurgery, where she was noted to have subtle gait instability and dexterity changes involving her right hand. Urgent neurosurgical intervention of the foramen magnum meningioma was performed, and the patient recovered well. Stereotactic fractionated radiotherapy was recommended for the cavernous sinus meningioma.
Discussion
Although meningiomas are the most frequent type of intracranial neoplasm, cavernous sinus meningiomas are rare, infiltrative meningiomas, with a documented incidence of 0.5 per 100,000. CSMs pose clinical challenges due to their location within the cavernous sinus and their infiltrative behavior.
The cavernous sinus is a dural venous sinus overlying both sides of the sella turcica, containing cranial nerves III, IV and VI, trigeminal nerve branches V1 and V2, and the internal carotid artery.When a mass occupies the cavernous sinus, there is often resultant unilateral ophthalmoplegia as a result of compression of the structures within the cavernous sinus.
The natural history of CSM is variable. More than 50% of cavernous sinus meningiomas present with progressive ophthalmoplegia, while nearly 20% are found incidentally. Thirty percent present with mild, nonspecific symptoms including headache, intermittent diplopia or nonspecific pain. Some patients are able to achieve clinical stability without intervention, and others demonstrate worsening ophthalmoplegia. CSMs often engulf nerve sheaths, encase vasculature and infiltrate bony structures. Treatment options may include temporizing medications, observation, radiotherapy or surgery. With or without intervention, CSMs often result in significant physical and emotional morbidity, given the anxiety that manifests when patients are diagnosed with an intracranial mass, in addition to incomitant strabismus and resultant diplopia, which are difficult to treat, headaches and other symptoms associated with these infiltrative lesions.
Sequelae following intervention for CSM include new or worsening neuropathy and ophthalmoplegia. Successful surgical intervention is limited by frequently incomplete resection due to the infiltrative nature of CSM, requiring dissection of involved structures. Radiotherapy can cause optic neuropathy due to the sensitivity of the optic nerve to radiation, as well as other neuropathies due to inadvertent exposure to therapeutic radiation.
This case presents a previously comitant convergence insufficiency-type exotropia that became incomitant with worsening diplopia, revealing a partial CN III palsy with pupillary involvement, after clinical stability for several years. This likely represents a slowly enlarging and/or dormant CSM that became more infiltrative and highlights the importance of regular clinical monitoring of patients with diplopia.
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- For more information:
- Allison Coombs, DO, MS, and Sylvia H. Yoo, MD, can be reached at New England Eye Center, Tufts University School of Medicine, 800 Washington St., Box 450, Boston, MA 02111; website: www.neec.com.
- Edited by Christine Benador-Shen, MD, and Malgorzata Dymerska Peterson, MD. They can be reached at New England Eye Center, Tufts University School of Medicine, 800 Washington St., Box 450, Boston, MA 02111; website: www.neec.com.