Patient has recurrent redness, pain of left eye

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A 38-year-old female presents with recurrent redness, pain, blurry vision, and protrusion of the left eye. Exam was remarkable for mild proptosis. What is your differential diagnosis?

By Audrey C. Ko, MD, Basil K. Williams, MD, Rebecca A. Shields, MD, Sander R. Dubovy, MD, and Wendy W. Lee, MD, MS; Bascom Palmer Eye Institute Grand Rounds Editors: Jonathan S. Chang, MD and Aleksandra V. Rachitskaya, MD

A 38-year-old female presented to the Bascom Palmer Eye Institute emergency room with a 1-week history of recurrent episodes of redness and pain of the left eye. She also reported protrusion of the left eye, and pain with left lateral gaze without diplopia.

Review of symptoms was positive for mild heat and cold intolerance, but was otherwise negative. The patient’s medical, surgical, and family histories were unremarkable.

Examination

The patient’s best-corrected vision was 20/20 and 20/25 in the right and left eyes, respectively. Her pupils were equal, round, and reactive without a relative afferent pupillary defect.

IOP, confrontational visual fields, and ocular motility were within normal limits.

Hertel measurements were 16 and 20 mm of the right and left eyes, respectively.

The patient had full-color plates of both eyes and no red desaturation.

Eyelid and corneal sensations were within normal limits.

Slit lamp and dilated fundus exam were unremarkable, with normal appearing optic nerves without pallor or edema, and no retinal striae.

Diagnostic course

The finding of proptosis is concerning for an orbital mass. The differential diagnosis is broad and includes inflammatory (idiopathic orbital inflammatory syndrome, thyroid eye disease, sarcoid, vasculitis), vascular (carotid cavernous fistula, cavernous hemangioma), neoplastic (cavernous hemangioma, glioma, meningioma, rhabdomyosarcoma, neurofibroma), metastatic (breast, lung, or prostate), lymphoid (lymphoma, benign reactive lymphoid hyperplasia), infectious (abscess, cellulitis), and other etiologies (mucocele, dermoid cyst, epidermoid cyst).

Imaging studies were obtained (Figure 1).

An ocular ultrasound showed a well-defined extraconal mass extending from the orbital rim to the apex superiorly. The mass was minimally enhancing on CT of the orbits and did not demonstrate any bony erosion. The MRI was consistent with these findings, showing a minimally enhancing mass in the superior orbit. A Humphrey Visual Field 30-2 did not show any evidence of visual field loss.

The next step in management was a biopsy of the mass, which was performed via a left anterior orbitotomy. The results were non-diagnostic. Since the patient was asymptomatic and there were no signs of visual compromise, observation versus surgical resection was discussed with the patient and she elected for observation.

Two years later, the patient presented with left orbital pain that had worsened significantly over a 1-week period. Exam showed normal visual acuity, no afferent papillary defect, and no restriction.

However, compared with her previous exam, she had increased proptosis with Hertel measurements of 16 and 23 mm of the right and left eyes, respectively.

She also had new onset of decreased sensation along the left medial canthus and medial and lateral upper eyelid with intact corneal sensation, which was suggestive of extension of the mass into the superior orbital fissure, outside of the annulus of Zinn.

Repeat ocular ultrasound, CT of the orbits, and MRI of the orbits again showed a minimally enhancing mass located in the superior orbit that now extended through the superior orbital fissure. Due to concern for gradual compression and compromise of the optic nerve, the mass was removed via a left superior craniotomy. The morphologic features of the pathology specimen were that of a schwannoma (Figure 2).

Physical exam did not reveal any café au lait spots, axillary or inguinal freckling, or nodules. Postoperatively, the patient initially had diplopia with upgaze that resolved within 3 months. A repeat MRI of the orbits was negative for recurrence at 6 months.

Discussion

Schwannomas-which are also known as neurilemomas-typically affect young and middle-aged adults and have a slight female predominance. Although they are common peripheral nerve tumors that typically affect sensory nerves, they are infrequently found in the head and neck region and account for 1% to 4% of orbital tumors.

In decreasing order of frequency, orbital schwannomas typically affect the ophthalmic branch (V1) of the trigeminal nerve, followed by the supraorbital and supratrochlear nerves, and less commonly the infraorbital nerve.

Schwannomas are of neural crest origin and demonstrate proliferations of Schwann cells that are encapsulated by perineurium. Histologically, these tumors are comprised of cells demonstrating both a dense proliferation of schwann cells in an Antoni A pattern, and also a loose proliferation of schwann cells with mucoid stroma in an Antoni B pattern (Figure 2). They also stain positively for S-100 and vimentin.

These tumors are well-encapsulated and fusiform in shape, and are usually slow-growing and noninvasive. Although they are considered a relatively benign lesion, they can cause pain, motor limitations, and compression of the optic nerve. Asymptomatic lesions that are not causing visual symptoms may be observed, but surgical resection is recommended when there is risk of optic nerve compromise.

Postoperatively, patients need to be monitored at regular intervals for recurrence.

Additionally, these tumors are associated with neurofibromatosis type 1 in 2% to 18% of patients and may undergo malignant transformation. Therefore, systemic workup is recommended in patients with orbital schwannoma.

Conclusion

Orbital schwannomas are relatively benign lesions and can be observed.

However, patients need regular monitoring for signs of optic nerve compression and surgical resection is recommended once vision is affected or if the patient starts exhibiting functional problems related to the mass.

References

1.     Cantore W. Neural orbital tumors. Current Opinion in Ophthalmology: vol 11(5), Oct 2000.

2.     Gunduz K,et al. Orbital schwannoma: correlation of magnetic resonance imaging and pathologic findings. Graefes Arch Clin Exp Ophthalmol. 241 (2003).

3.     J. Rootman, C. Goldberg, W. Robertson. Primary orbital schwannomas. Br J Ophthalmol. 66 (1982).

4.     Yanoff M and Sassani JW. Ocular Pathology. 6th edition. Mosby: China., 2009.

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