A case of mammary analog secretory carcinoma of the lower lip

A new disease concept called mammary analog secretory carcinoma (MASC) has been reported recently among acinic cell carcinoma (AciCC) of the salivary gland and cystadenocarcinoma of low malignant potential. MASC exhibits histological and immunohistochemical findings similar to those of secretory carcinoma of the breast. Recently, it has been pointed out that a considerable number of cases believed to be AciCC are in fact cases of MASC. We report our experience with a case of MASC that developed on the lower lip after originating from the minor salivary glands. The patient was a 41-year-old man who consulted our department with a chief complaint of a painless mass on the right lower lip. After a clinical diagnosis of a benign tumor, the mass was surgically excised with the patient under local anesthesia. Histopathological examination of the excised mass indicated AciCC. Two years postoperatively, metastasis to the submandibular lymph nodes was observed, for which right suprahyoid neck dissection was performed. No subsequent local recurrence or distal metastasis has been observed. This case was originally diagnosed as AciCC, but was diagnosed as MASC on histopathological reexamination.