喉頭原発の悪性筋上皮腫の1例

Malignant myoepithelioma in the larynx：A case report

I．はじめに

　筋上皮腫は腺組織に存在する筋上皮細胞由来で，全唾液腺腫瘍の1％以下の頻度とされる稀な腫瘍であり，悪性例となるとさらに少ない¹⁾。発生部位としては口腔内の小唾液腺や耳下腺からの報告例が多いが，喉頭原発症例はきわめて稀である¹⁾。われわれが渉猟し得た限りでは喉頭原発の悪性筋上皮腫は海外で1例の報告²⁾があるのみで，わが国での報告例は存在しなかった。今回われわれは喉頭原発の悪性筋上皮腫症例を経験したので，症例を呈示し診断および治療方針について文献的考察を加えて報告する。

　Malignant myoepithelioma is rare tumor of the salivary gland accounting for about 0.2 to 0.5％ of all salivary gland tumors.

　A 52-year-old man was complaining of hoarseness. He had a mass on smooth surface in the laryngeal supraglottic area. Surgical resection（partial laryngectomy）and postoperative radiotherapy（total 65Gy）were performed. Histopathologically,the tumor was composed of relatively small-round and spindle cells with nuclear atypism. Small and large solid tumor nests were found. Immunohistochemical studies showed positive staining for vimentin,Myo-D1,and S-100 protein. The diagnosis of malignant myoepithelioma was made. After the operation,no evidence of recurrence was observed for 21 months.