A case of renal clear cell carcinoma presenting with a metastatic lesion in the oropharynx

Metastatic tumors involving the oral mucosa are rare, comprising 1 to 3% of all malignant oral neoplasms. Metastatic renal cell carcinoma invading the soft tissue of the oral cavity is extremely rare. Furthermore, metastatic renal cell carcinoma of the soft tissue of the oral cavity as the presenting feature is very rare. We report a case of metastatic renal cell carcinoma that initially presented to us with a tumor of the oropharynx. The patient was a 65-year-old man who visited our department complaining of discomfort in the throat. Fiberoptic endoscopic examination revealed a tumor on the dorsal aspect of the oropharyngeal soft palate. Tumor biopsy revealed no malignant findings. On the basis of the findings on contrast-enhanced computed tomography (CT), the tumor was suspected as a hemangioma and trans-oral tumor resection was performed. Postoperative histopathological examination revealed findings consistent with clear cell carcinoma. Further examinations revealed a tumor in the right kidney. Nephrectomy was performed and the tumor was diagnosed as a clear cell carcinoma. In patients presenting with oral tumors that do not show typical histopathological findings such as squamous cell carcinoma, whole-body examination is recommended considering the possibility of metastatic tumor.