中耳コレステリン肉芽腫症を呈した耳管鼓室口金属異物例

抄録

We encountered a case of cholesterol granuloma caused by an iron fragment trapped at the tympanic orifice of the eustachian tube. The patient was an 80-year-old man who presented with a 4-year history of recurrent bloody otorrhea on the left side. While he was engaged in iron welding 25 years ago, a molten iron fragment had accidentally entered his left ear. Two weeks after the welding accident, the patient had undergone tympanoplasty at another hospital, and postoperative audiometry had revealed total deafness in the left ear.

High-resolution temporal bone CT revealed a high-density material measuring 4 mm in diameter that appeared to be a metal piece at the tympanic orifice of the eustachian tube. Tympanoplasty was performed for the purpose of removing the foreign body. Granulation tissue around the mastoid antrum, superior tympanic cavity, and ossicles was removed, and then the foreign body trapped in the tympanic orifice of the eustachian tube was separated and removed. Histopathological examination of the granulation tissue in the mastoid antrum revealed a cholesterol granuloma. The otorrhea resolved postoperatively, and 6 months after the surgery, CT no longer revealed any diffuse soft tissue opacity in the middle ear cavity. Cholesterol granuloma in this case was presumably caused by long-term obstruction of the eustachian tube by the foreign body.