Hoshino Miyako, Inoue Katsuyuki, Kaneda Tomohisa, Nishimura Michiko, Kusama Kaoru, Sakashita Hideaki, Sato Yukiko, Takeuchi Kengo, Nagao Toshitaka, Kikuchi Kentaro
Division of Pathology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 350-0283, Japan.
Second Division of Oral and Maxillofacial Surgery, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 350-0283, Japan.
Case Rep Dent. 2021 Oct 20;2021:5557247. doi: 10.1155/2021/5557247. eCollection 2021.
Clear cell carcinoma (CCC) is a rare entity in the salivary gland tumor. So far, only 10 cases of primary CCC of the buccal mucosa have been reported. Here, we first report an extremely rare case of buccal CCC with the fusion gene. The patient, a 69-year-old woman, presented with a painless mass in the right buccal mucosa. The tumor, which had been present for about 10 years, measured approximately 15 mm in diameter and was pedunculated, elastic hard, smooth, and mobile. Histopathological examination revealed proliferating tumor cells with vacuolated and clear cytoplasm partially surrounded by hyalinized stroma. The tumor was not encapsulated, and no contact with the overlying epithelium was evident. Duct-like structures were occasionally observed in the tumor nests composed of clear cells. The tumor had invaded into surrounding muscle and adipose tissues. Immunohistochemical examination revealed that the clear cells were positive for epithelial cell markers, and myoepithelial markers were negative. Fluorescence in situ hybridization (FISH), performed to search for genetic abnormalities, demonstrated split positivity for , and fusion with was confirmed. These findings suggested a diagnosis of CCC.
透明细胞癌（CCC）在涎腺肿瘤中是一种罕见的实体。迄今为止，仅报道过10例颊黏膜原发性CCC。在此，我们首次报告1例极其罕见的伴有融合基因的颊部CCC病例。患者为一名69岁女性，表现为右侧颊黏膜无痛性肿块。该肿瘤已存在约10年，直径约15毫米，有蒂，质地硬且有弹性，表面光滑，可活动。组织病理学检查显示肿瘤细胞增生，细胞质呈空泡状且透明，部分被玻璃样变的间质包绕。肿瘤无包膜，与上方上皮无明显接触。在由透明细胞组成的肿瘤巢中偶尔可见导管样结构。肿瘤已侵犯周围肌肉和脂肪组织。免疫组织化学检查显示透明细胞上皮细胞标志物呈阳性，肌上皮标志物呈阴性。为寻找基因异常进行的荧光原位杂交（FISH）显示 呈分裂阳性，且证实与 融合。这些发现提示诊断为CCC。
