術後性乳突嚢胞の1症例

A Case of Postoperative Mastoid Cyst

　はじめに

　乳突嚢胞は乳突洞に形成される嚢腫の総称である。成因としては慢性炎症，外傷，先天奇形などが考えられているが明らかでない。その多くは原発性に発生したもので^1〜11），術後に発生した症例の報告は少ない^1,12〜14）。

　今回，慢性中耳炎手術後に生じた乳突嚢胞の1症例を経験したので，その発生機序，治療について文献的考察を加え報告する。

The postoperative mastoid cyst (POMC) is rela-tively rare. A 61-year-old man was complaining of brownish aural discharge, hearing loss and aural fullness. He underwent tympanoplasty with closedmastoidectomy eight years before. CT and MRI revealed a cystic mass which occupied the mastoid cavity and extruded into the external auditory canal. The entire cyst wall was removed along with coexistent cholesterol granulomas, and the mastoid cavity was obliterated with local flaps. Simultane-ously, tympanoplasty was performed and his hear-ing was improved after surgery. Chronic inflamma-tion which prevented the ventilation of and the drainage from the middle ear space could have caused the POMC in the present case.