耳下腺に発生した基底細胞腺腫の1例 A case of basal cell adenoma in the parotid gland
A 30-year-old man was referred to our department because of pain in the right pre-auricular region on mouth opening. Physical examination revealed a round, hard mass, about 25mm in diameter, in the parotid gland. Computed tomography (CT) showed a round, well-circumscribed mass. An oval mass measuring about 5×10mm was detected inside the tumor on CT. The clinical diagnosis was a benign tumor of the right parotid gland, and superficial parotid lobectomy was performed. Histopathologically, the tumor was characterized by multiple duct-like structures or solid and trabecular masses composed of small isomorphic cells with hyperchronic, round nuclei and eosinophilic cytoplasm. A basal cell adenoma was diagnosed on the basis of these findings. The inner small mass of the tumor showed lymphadenopathy. Immunohistochemical examination showed that the inner epithelial cells of the tubular tumor nests were positive for keratin, and the outer cells were positive for a-smooth muscle actin and vimentin. The stromal cells stained positively for S-100 protein, α-smooth muscle actin, and vimentin, and stained negatively for keratin. The positive ratio of Ki-67 was 6.1%, which indicated relatively low rate of Ki-67 positive cells, supported the diagnosis of a basal cell adenoma.
日本口腔外科学会雑誌 51(7), 352-355, 2005-07-20
Japanese Society of Oral and Maxillofacial Surgeons