Primary Oral Mucinous Adenocarcinoma in minor salivary gland

Oral Mucinous Adenocarcinoma is a rare malignant neoplasm characterized by large amounts of extracellular epithelial mucin-containing small cordlike and nestlike clusters of epithelium. The purpose of the current study was to describe a rare case of primary mucinous adenocarcinoma in the minor salivary gland and its immunohistochemical features. A 64-year-old man was referred for evaluation of a swelling located in the left side of the mandible. A fine needle aspiration cytology revealed atypical neoplastic cells with increased and hyperchromatic nuclei. An incisional biopsy showed lakes of mucin loculated by fibrotic stroma. In the mucin pools, tumor cells could be observed floating both individually and in small clumps, either solid or clustering around microlumin. Necrotic areas were not noticed. Considering all these features, the final diagnosis was mucinous adenocarcinoma. The patient was directed to the oncology department for treatment and has remained disease free with no sign of cervical lymph nodes during the 27 months follow-up period. An immunohistochemical panel was performed and the tumor presented positive staining for Ki-67, MCM2, 34β12, AE1AE3, CK 18, Glut 1, EMA, E-Caderin, CK 19, CD 138 and CK 7.