A Case of Secretory Carcinoma That Occurred in the Buccal Submucosa

Abstract

Secretory carcinoma (SC) is a malignant salivary gland tumor that has been first reported by Skalova et al. in 2010. Histologically, it shows solidity infiltrated with very small cystic cavities and cribriform and papillary features and includes periodic acid-Schiff stain-positive, acid-fast secretions. The cells have oval nuclei, and vacuolated cytoplasm and foamy secretions are seen. Anaplasia is not strong and mitotic figures are rarely seen. These features closely resemble AciCC. Immunohistologically, it is thought to be positive for S-100 protein, vimentin, and mammaglobin and negative for DOG1. The presence of the ETV6-NTRK3 fusion gene is essential in diagnosing secretory carcinoma. In this report, we describe a case of SC in a 52-year-old woman. She was referred to our center because of a mass in left buccal mucosa. A soft and elastic submucosal mass measuring approximately 10 mm × 10 mm in size with a smooth surface was seen in the buccal mucosa in an area corresponding to the left mandibular canine to premolars. The imaging findings revealed that a high-intensity lesion was seen on T2-weighted images. Immunohistochemicalstaing for S-100 protein and vimentin were positive. Furthermore, genetic examination detected the presence of the ETV6-NTRK3 fusion gene. Based on these findings, the definitive diagnosis was secretory carcinoma.