2009 Volume 21 Issue 4 Pages 279-284
A female patient in her 70s was referred to our department because of pain and a mass on the floor of the mouth in the left mandibular molar area. The mass (30×8 mm) extended in the direction of the mandibular ramus, and was palpable in the submucosal area between the lingual gingiva of the left mandibular first molar-equivalent area and the floor of the mouth. Nine years ago, a mass developed in the lingual nerve, and a biopsy performed in a local dental hospital revealed neurofibroma. In the present case, the mass was resected under a tentative diagnosis of a mouth floor tumor. Macroscopic observation showed that part of the lingual nerve was tuberously swollen, and the mass was histologically diagnosed as adenoid cystic carcinoma. As the surgical margin was positive for cancer, mouth floor resection and left supraomohyoid neck dissection were also performed. The results of the histological investigation indicated that this case was a relatively rare one of primary tumor of the sublingual gland. The present case was initially considered to differ from the mass nine years ago. However, we obtained a specimen of the mass taken nine years ago, and judged that it was also adenoid cystic carcinoma. Therefore, it was suggested that the mass in the present case developed from that which previously formed in the lingual nerve through tumor infiltration.
