Nasopharyngeal carcinoma, the most common carcinoma to involve the skull base, may present with neuro-ophthalmic features. Most patients have multiple cranial nerve dysfunction, the fifth and sixth cranial nerves being most often affected (1-3). We report a case that presented with third cranial nerve palsy as the only neuro-ophthalmic feature. A 48-year-old man with no significant past medical history presented to our clinic with a complaint of diplopia and ipsilateral periocular pain of 3 days’ duration. The patient also reported having noticed a mass in the left submandibular area 6 months earlier. Neurologic examination revealed partial right ptosis and complete absence of adduction, supraduction, and infraduction of the right eye. The pupils in low illumination were equal at 4 mm and symmetrically reactive to light and near targets. Visual acuity, ophthalmoscopy, and cranial nerve and motor examination results were normal. Results of the remaining physical examination were within normal limits except for a painless mass over the left submandibular area. All laboratory values and were within the normal ranges. MRI of the brain and nasopharynx showed a large mass centered at the clivus region and spreading into the nasopharynx, invading the basis of the occipital bone, both sphenoid and posterior ethmoid sinuses, the medial part of the right cavernous sinus, and the petrous apex (Fig. 1A-B). The mass enhanced heterogeneously. The superior and inferior orbital fissures, optic nerves, and other intraorbital structures were spared. Significant bilateral lymphadenopathy of the neck was evident and some lymph nodes showed hypodense centers indicative of necrosis. A digital subtraction angiogram revealed no vascular abnormalities.FIG. 1: A. T2 axial MRI shows a tumor with mixed signal intensity that is invading the sphenoid and posterior ethmoid sinuses. B. Postcontrast coronal MRI shows an enhancing tumor centered at the clivus with partial right cavernous sinus invasion (arrow).Biopsy of the nasopharyngeal mass revealed a nonkeratinizing differentiated carcinoma (Fig. 2). The patient was referred to the oncology department for radiotherapy and chemotherapy.FIG. 2: Histopathology of a nasopharyngeal punch biopsy shows fibrous connective tissue with infiltrating cords of anaplastic cells (hematoxylin and eosin, 340).The third cranial nerve paralysis remained stable without improvement, and no other neurologic symptoms had occurred after 3 months. A retrospective study of 79 patients with nasopharyngeal carcinomas (4) disclosed that one quarter of these patients have neuro-ophthalmic manifestations. In a group of 564 patients with nasopharyngeal carcinomas (1), cranial nerve dysfunction was present in 12%. In 92% of the patients, neurologic deficits were confined exclusively to cranial nerves. Another study (5) showed that the most frequently affected cranial nerves were the fifth and sixth. Our patient is unusual in that the third cranial nerve was the only one involved. The extent of the tumor on MRI fails to indicate why the third cranial nerve was the only affected cranial nerve. Yesim Yetimalar Beckmann, MD Benian Deniz, MD Department of Neurology Atatürk Training and Research Hospital Izmir, Turkey [email protected] Fazil Gelal, MD Department of Radiology AtatÜrk Training and Research Hospital Izmir, Turkey Yaprak Seçil, MD Department of Neurology Atatürk Training and Research Hospital Izmir, Turkey