Sir,

Nasopharyngeal carcinoma (NPC) typically presents to ophthalmologists with one or more cranial nerve palsies. The fifth and sixth nerves are the most commonly affected.1 Although ocular symptoms with cranial nerve involvement are not uncommon in patients with NPC, they often become evident several months or years after the malignancy is diagnosed. We present a case of optic neuritis as the first clinical manifestation of NPC.

Case report

A 55-year-old Taiwanese woman presented with pain and decreased vision in the right eye of about one week duration. There were no other systemic symptoms, in particular symptoms suggestive of NPC. There was no significant past medical or ocular history. General physical examination was normal. Best-corrected visual acuity was 6/10 in the right eye and 6/6 in the left eye with a normal anterior segment. Intraocular pressures were within normal limits. Examination of the left fundus was unremarkable. Posterior segment examination on the right showed mild disc swelling. There was a right relative afferent pupillary defect. The ocular motility was full. A computed tomography (CT) scan was arranged, but the patient refused for personal reasons.

After 3 weeks the visual acuity in the right eye had deteriorated to 6/60 and colour vision had also decreased. The fundus examination of the right eye revealed moderate disc swelling (Figure 1). The Goldmann visual field demonstrated a constriction of the right visual field. A diagnosis of optic neuritis was made and the patient was given 1 g of intravenous methylprednisolone for 3 days and then commenced on oral prednisolone 60 mg daily on a reducing regime. The visual acuity in the right eye improved to 6/7.5 after 3 weeks. The patient was reviewed and was finally persuaded to undergo the CT examination, which demonstrated a space-occupying lesion in the sphenoid sinus (Figure 2) and erosion of the skull base. There was no evidence of tumor infiltration to the orbital cavity. Nasopharyngoscopy showed a tumor mass over the roof of the nasopharynx on the right with skull base invasion. Tissue biopsy revealed a ‘non-keratinizing squamous cell carcinoma’. The patient was referred for further management of the NPC with radiotherapy and chemotherapy and followed up in the ophthalmic clinic for 6 months. During this period the patient regained 6/6 vision and normal colour vision in the right eye. One year after completing the radiotherapy and chemotherapy the patient developed right sixth and seventh cranial nerve palsies.

Figure 1
figure 1

Colour fundus showed a hyperemic disc swelling, especially in the nasal side.

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Figure 2
figure 2

Brain CT scan disclosed a space-occupying lesion situated in the sphenoid sinus.

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Comment

NPC has a striking geographic distribution, with especially high rates in southern China, Hong Kong, and Taiwan. It commonly manifests as a neck mass, nasal obstruction, nasal bleeding, and occasionally hearing loss. Abducens or oculomotor nerve palsy can often be the presenting ocular feature. These are primarily due to tumor invasion of the cavernous sinus and/or skull base. However, early invasion of the optic nerve is very rare.2,3 Optic nerve involvement often occurs in the late stage of the disease process and is usually associated with direct tumor invasion of the orbit. In the present case, there were no extraocular signs or evidence of direct tumor invasion around the optic nerve.

Two cases of optic neuritis have been reported previously as the initial presentation of NPC.4,5 Presad and Doraisamy4 reported five cases of NPC with optic nerve involvement, one of which manifested initially as a retrobulbar optic neuritis due to extension of the tumor along the medial orbital wall to involve the optic nerve. Hoh et al5 described a case of NPC, which presented initially as optic neuritis. No evidene of a tumor mass around the optic nerve or any histological evidence of tumor infiltration was documented. A possible remote effect of NPC was postulated.

In conclusion, the present report highlights that optic neuritis, a common cause of acute visual loss, can be a rare initial manifestation of NPC. Although it is unclear whether this complication is due to a paraneoplastic effect, clinicians should be aware that NPC can present as retrobulbar/optic neuritis.