放射線治療と免疫チェックポイント阻害薬が有効であった耳下腺上皮筋上皮癌再発例

Radiation therapy and immune checkpoint inhibitors in recurrent epithelial myoepithelial carcinoma of the parotid gland

はじめに

　上皮筋上皮癌は全唾液腺腫瘍の約1％，唾液腺悪性腫瘍の約2％を占める比較的稀な低悪性腫瘍である^1）。治療の第一選択は手術で放射線治療の効果に対する報告は少数である。今回，耐術能のない耳下腺上皮筋上皮癌の再発例に放射線治療と免疫チェックポイント阻害薬（immune checkpoint inhibitors：ICI）が有効であった1例を経験したため，若干の考察を加えて報告する。

　A 91-year-old man who had undergone resection of a left parotid epithelial myoepithelial carcinoma 8 years and 7 months ago, visited our hospital for a relapsed tumor. He had a 6cm-sized parotid tumor infiltrating the skin, but no lymph node or distant metastases. He was determined unsuitable for general anesthesia owing to complications of bronchial asthma and COPD. He received 70 Gy of radiation therapy, and the tumor shrank significantly. In addition, the patient was receiving pembrolizumab, and the tumor continued to shrink.

　Radiation therapy and immune checkpoint inhibitors may be options for inoperable cases of salivary gland epithelial myoepithelial carcinomas.