側頭骨にみられたmonostotic fibrous dysplasiaの1例

A Case of Monostotic Fibrous Dysplasia of the Temporal Bone

I．はじめに

　慢性に骨の腫脹をきたす良性疾患で，骨髄の線維性結合織による置換を主病変とするfibrous dysplasiaは，1938年Lichtensteinの命名以来広く用いられている。本疾患は全身骨を侵し，単純性，多発性に生じうるため，そわ以前は種々の名称が与えられていた。主に長管骨に認められることが多いが，頭蓋・顔面骨にもいくつかの報告例がある。側頭骨に限局したfibrous dysplasiaは，著者らの知る限りでは文献上18例の報告がなされている。その中で2例は内耳道の狭窄，感音難聴を示していたが，今回著者らの経験した症例も同様の所見を呈し，かつ潜在的顔面神経麻痺および眼振異常が認められたので，ここにその症例を報告するとともに，文献的考察を加えて検討した。

　A 47-year-old male with fibrous dysplasia of the temporal hone was reported. He had been suffering from progressive sensorineural hearing loss of the left ear. At the first visit there were abnormal findings in skull X-ray films showing a large opaque mass in the left temporal area and also in EMG analysis. In order to prevent further facial paralysis, facial nerve decompression was performed. Histological examination revealed the typical features of fibrous dysplasia. Other abnormal clinical signs were contralateral gaze nystagmus and downbeat nystagmus when the eyes were closed and the head was down. However, the relationship between these signs and fibrous dysplasia was still unknown.