外転運動障害で初発した上咽頭癌の1例

Abducens palsy as the initial manifestation in a case of nasopharyngeal carcinoma

　59歳男性が10か月前から複視を自覚した。既往として約30年にわたる右聾があった。初診時に右眼の外転神経麻痺があり，コンピュータ断層画像（CT）と磁気共鳴画像（MRI），上咽頭生検により，海綿静脈洞にまで浸潤した上咽頭癌と診断された。腫瘍は耳管を閉塞させた後に頭蓋内浸潤し，海綿静脈洞の外転神経を障害していた。以前からの聾のため耳症状を自覚せず，眼症状のみを主訴に診断に至った。眼球運動において外転障害を呈する症例では，上咽頭腫瘍も鑑別疾患として常に念頭におくべきと考えられた。

A 59-year old male presented with diplopia of 10 months' duration. He had had hearing loss in his right ear since 30 years before. He was diagnosed with right abducens palsy. A nasopharyngeal tumor invading the cavern-ous sinus was detected by computerized tomography (CT) and magnetic resonance imaging (MRI). The tumor had invaded the base of the skull after choking the auditory tube. Biopsy led to the diagnosis of nasopharyngeal carcinoma. His abducens palsy was apparently due to invasion of carcinoma into the cavernous sinus. He failed to detect auditory symptoms because of his hearing loss. This case illustrates that abducens palsy may be the initial manifestation of naso-pharyngeal carcinoma.