Intracerebral Epidermoidに合併したAspergillosisの1症例—Case Report

A Case of Intracerebral Epidermoid Associated with Aspergillosis

I．はじめに

　中枢神経系のaspergillosisは従来稀な疾患として扱われてきたが^10），抗生物質や免疫抑制剤あるいは副腎皮質ステロイドが頻用されるに従い最近では上一般的な疾患になりつつある^12）．しかし，脳内に主病巣を形成したepidermoidにaspergillosisを合併した症例は，われわれの渉猟した限り認められなかったので，画像診断上の特徴・治療上の注意点を呈示し，若干の考察を加え報告する．

A case of intracerebral epidermoid associated with aspergillosis, which spread from the middle ear to the left temporal lobe, is reported. A 58-year-old woman was admitted on 6 June 1988, complaining of left tem-poralgia and motor aphasia. She had suffered from It. chronic otitis media with cholesteatoma and had under-gone a radical operation 11 years previously. CT scan revealed low density area with a mass effect in It. tem-poral lobe. Bone image coronal CT scan revealed de-struction of the roof of the pyramidal bone had resulted in communication between abscess cavity and external auditory meatus. On MRI scan It. temporal lobe showed low signal intensity on T,WI, and high signal intensity on T2WI. In spite of strong antibiotic che-motherapy, mass effect on CT scan showed no sign of improvement. We performed total removal of the abs-cess on 15 July 1987.

A number of characteristic aspergillus hyphae were recognized in the resected cyst. As the cyst wall con-sisted of keratinising squamous epithelium intermingled with granulation tissue, we had a diagnosis of epidermoid cyst.

The diagnosis of epidermoid associated with aspergil-losis was difficult. CT findings of epidermoid in gener-al, show homogeneous low density without enhance-ment, but, in our case, CT scan showed heterogeneous low density area with capsular high dense. MRI of epidermoid usually shows a low signal intensity on T₁WI, but our case showed iso-low signal intensity on T₁WI.

In spite of a poor prognosis of aspergillosis of the CNS, our patient has recovered well due to receiving prompt surgical treatment.