Mammary analogue secretory carcinoma （MASC） is a newly defined salivary gland tumor reported by Skálová et al. in 2010. The most characteristic feature of this tumor is detection of ETV6-NTRK3 （EN） fusion gene. In this report, we describe a case of MASC in a 50-year-old woman. She was referred to our department because of respiratory discomfort. A mass measuring 140 × 90 × 85 mm was detected in the right submandibular region. The imaging findings revealed that the mass contained both solid and cystic areas. Because low-grade adenocarcinoma was suggested, tumor excision with radical neck dissection was performed. Histological examination showed a solid and follicular, papillary structure. The secretory material stained positively for PAS. Immunohistochemical staining for S-100 protein and vimentin were positive. Furthermore, genetic examination revealed the presence of the EN gene, which led to final diagnosis of MASC.
