A case of secretory carcinoma of the minor salivary gland in the buccal mucosa

Abstract Secretory carcinoma (SC), previously described as mammary analogue secretory carcinoma, is a new subtype of salivary gland cancer that was added to the World Health Organization’s classification of head and neck tumors in 2017. Although salivary gland cancer in the minor salivary glands is relatively rare, this disease is difficult to diagnose because of its various pathological tissue images and subtypes. In this report, we describe an SC tumor that occurred in the buccal mucosa and originated in the minor salivary glands. The patient was a 53-year-old man who noticed a mass in his right buccal mucosa. The lesion was initially clinically diagnosed as a benign tumor, but was later surgically excised from the patient under local anesthesia at another hospital. The tumor was pathologically diagnosed as malignant and some of the tumor remained following the initial surgery and the patient was referred to our department for additional surgical treatment. After surgical resection under general anesthesia, histopathological examination of the tumor suggested it was SC. Immunohistochemical staining revealed strongly positive staining for S100, vimentin, and mammaglobin and negative staining for DOG-1 and identify of the ETV6-NTRK3 gene fusion in the tumor cells. Although no subsequent local recurrence or metastasis was observed three years post-operation in this case, standardized treatment protocols and diagnostic methods are generally still lacking for SC. Salivary gland cancers in the minor salivary glands are relatively rare, but differential and accurate diagnosis is important.