we examined a 68-year - old man who had been suffering from diplopia for a week .
the patient had been diagnosed with a nasopharyngeal squamous cell carcinoma 8 months prior and had received cisplantin - based chemotherapy with radiotherapy . on the first examination , 8-prism diopter right esotropia in the primary position and a remarkable limitation in abduction in his right eye were observed .
the marginal reflex distance 1 ( mrd1 ) was 3 mm in the right eye and 5 mm in the left .
in addition to right mild ptosis , anisocoric pupils with a smaller right pupil were found and the anisocoria increased in the dark .
after topical application of 0.5% apraclonidine ( iopidine ; alcon , fort worth , tx , usa ) , the patient 's right pupil dilated from 2.5 mm to 5 mm in bright light and the right mrd1 increased from 3 mm to 5 mm ( fig .
brain magnetic resonance imaging ( mri ) revealed newly appeared gadolinium - enhanced mucosal thickening in both sphenoid sinuses combined with bony destruction of the skull base .
these lesions extended to the right cavernous sinus with encasement of the internal carotid artery ( ica ) ( fig .
seven weeks later , the esotropia worsened and the limitation of abduction , anisocoria , and right ptosis persisted .
neither abducens nerve palsy nor horner 's syndrome provides an indication of the location of the lesion .
however , when both are present , it is important to localize the site of the lesion .
when these rare clinical features are manifested , we have to consider paratrigerminal syndrome or a lesion of the posterior cavernous sinus .
sympathetic nerve fibers travel over the wall of the carotid artery and in the cavernous portion the fibers leave the ica and accompany the abducens nerve for only a few millimeters in the posterior portion of the sinus   ( fig . 5 ) .
therefore , we could consider a posterior cavernous sinus lesion due to combined abducens nerve palsy .
furthermore , incomplete horner 's syndrome without anhydrosis , as in the case reported here , indicates the involvement of the periarterial sympathetic plexus at the third angulation point . to date , only 13 cases with this combination of symptoms secondary to metastatic neoplasm within the cavernous sinus have been reported [ 4,10 - 16 ] . regarding the primary lesions in these cases
, there were 1 small cell lung cancer , 1 parotid cancer , 1 breast cancer , 1 gastric cancer , 1 uterine cancer , 3 undetermined origins   and 3 nasopharyngeal cancers .
unlike in other three nasopharyngeal cancer cases reported by hirao et al . , the cancer only invaded the 6th nerve and sympathetic fiber without involvement of the 5th nerve in this case .
malignant tumors that affect the cavernous sinus commonly result in the 5th and the 6th nerve injuries .
the more medial location of the abducens nerve has been postulated as the reason for its frequent involvement when confronted with the compressive forces in a confined space or direct invasion . in this case , the nasopharyngeal cancer extended through the sphenoidal sinus demonstrated by brain mri and positron emission tomography ( fig .
therefore , the cancer affected only the 6th nerve without involvement the 3rd nerve , which occupies a superior position at the lateral wall of the sinus , in addition to the 4th and 5th nerve . although autopsy was not permitted and there was a limitation of anatomical access , we suggest that tumor cells in the sphenoidal sinus had spread to the 6th nerve in the cavernous sinus , and then perineurally metastasized to the oculosympathetic nerve fibers before joining the first division of the 5th nerve . a plausible alternative to cocaine or hydroxyamphetamine in the diagnosis of horner 's syndrome is apraclonidine , a direct -receptor agonist with strong 2 and weak 1 activity . in patients with horner 's syndrome , reversal of anisocoria and improvement of ptosis
with respect to the length of survival in patients with tumor invasion of the cavernous sinus region as reported in the literature , most individuals live no longer than six months and the ultimate outcome is a dismal 75% to 85% expected mortality within 2 years .
the patient described in this report died 5 months after the presentation of combination abducens nerve palsy with horner 's syndrome . in other words
, this manifestation may be a significant predictor of survival in addition to the location of the lesion .
this is the first reported case of abducens nerve palsy with horner 's syndrome due to tumor invasion into the cavernous sinus in a korean patient .
the presence of horner 's syndrome and the 6th nerve palsy should be cautiously investigated to confirm the existence of the cavernous sinus lesions .
 a 68-year - old male patient presented with a week of sudden diplopia . 
 he had been diagnosed with nasopharyngeal cancer 8 months prior and had undergone chemotherapy with radiotherapy . 
 eight - prism diopter right esotropia in the primary position and a remarkable limitation in abduction in his right eye were observed . 
 other pupillary disorders and lid drooping were not found . 
 after three weeks , the marginal reflex distance 1 was 3 mm in the right eye and 5 mm in the left eye . 
 the pupil diameter was 2.5 mm in the right eye , and 3 mm in the left eye under room illumination . under darkened conditions , 
 the pupil diameter was 3.5 mm in the right eye , and 5 mm in the left eye . 
 after topical application of 0.5% apraclonidine , improvement in the right ptosis and reversal pupillary dilatation were observed . on brain magnetic resonance imaging , 
 enhanced lesions on the right cavernous sinus , both sphenoidal sinuses , and skull base suggested the invasion of nasopharyngeal cancer . 
 lesions on the cavernous sinus need to be considered in cases of abducens nerve palsy and ipsilateral horner 's syndrome . 
Case Report
Discussion