耳下腺に発生した乳腺相似分泌癌の1例

A case of mammary analogue secretory carcinoma of the parotid gland

はじめに

　乳腺相似分泌癌（mammary analogue secretory carcinoma：MASC）は，今まで乳頭囊胞型，濾胞型，一部の微小囊胞型の腺房細胞癌とされていたものが，2010年にSkálováら^1）によって乳腺分泌癌と組織的に類似していることが示され，新たに提唱された疾患である。今回われわれは，耳下腺のMASCを診断・治療したため，若干の文献的考察を加えて報告する。

　A 31-year-old man presented with anterior ear mass on the right side for past one month. A 21 mm well-defined neoplastic lesion was observed in the right parotid gland. Preoperative fine-needle aspiration cytology revealed Class Ⅲb. Partial resection of the parotid gland was performed. The pathological diagnosis was mammary analogue secretory carcinoma（MASC）. After the operation, no recurrence or metastasis was observed at 10 month follow-up. MASC is a relatively new disease entity first reported in 2010, and the number of reported cases is small. Further documentation and analysis of cases are required in the future.