頭蓋内に進展した術後性乳突部嚢胞の1例

A Case of Postoperative Mastoid Cyst Extending into the Cranium

　はじめに

　乳突部嚢胞は多くが原発性であり，術後性に発症することは少ない^1〜22）。今回われわれは，頭蓋内に進展した巨大な術後性乳突部嚢胞の1例を経験したので報告する。

A 59-year-old female suffering from headache due to a huge mastoid cyst was reported. She had a middle ear operation 50 years ago. At the first visit,the posterior wall of the right external auditory canal was extensively bulged. CT showed a soft mass lesion in the mastoid cavity with extension to the posterior cranial fossa. Canal-down tympano-plasty type I was performed. The cyst with bone defect, located at the posterior wall of the mastoid cavity, was recognized and the cyst wall was removed totally except at the portion of adhesion to the posterior fossa dura. Histopathological exami-nation revealed cholesterol granuloma.