伊藤 真人

  真珠腫性中耳炎に病変の進展範囲に応じて外耳道を拡げるように乳突削開した後（Retrograde mastoidectomy on demand），側頭筋膜片を用いた軟組織にて鼓膜・外耳道を再建する術式を当科では用いている。削開範囲は外耳道を拡大し鼓室の開放にとどまるものから外耳道後壁骨を削除するものまで真珠腫の進展範囲に応じ決定される。長期経過後の術後聴力，真珠腫再発率，最終的な外耳道形態，聴力改善不良例について検討をおこなった。過去の報告と比較し，本術式では聴力経過は全体に良好であり，真珠腫再発率は外耳道を保存する場合より低く，外耳道を削除した場合と同程度であった。外耳道鼓膜の形態は様々であり，個々の中耳換気能により最終的な形態に落ち着くものと考える。また，聴力改善不良例は乳突部と耳管鼓室口への進展を多くみとめ，耳管機能不全が疑われた。聴力改善には中耳換気能が重要であると考える。

We report herein on a rare case of schwannoma of the chorda tympani with facial palsy. A 34-year-old woman was referred to our hospital because of right facial palsy which was resistant to steroid intervention and anti-viral drugs. In the physical examination, a white mass was observed in the posterior superior quadrant of the tympanic membrane and the facial palsy score was 0/40. Computed tomography revealed a tumor in the right chorda tympani, extending from the branch of facial nerve to the malleus. Based on the physical, physiological and imaging tests, the patient was diagnosed as having a tumor of the right chorda tympani with facial palsy. For the purpose of resection and definitive diagnosis of the tumor, a surgical intervention was performed. Histologically the tumor was diagnosed as a schwannoma, and immunohistochemically the tumor cells were positive for S-100. After surgery, the patient's facial palsy completely resolved in six weeks. There has been no finding of recurrence two years after surgery.