Oral metastatic clear-cell tumours: To and fro: Unusual case reports.

We report two extremely rare cases of metastatic clear-cell carcinomas, which metastasized from and to the oral cavity and both presented clinically in the oral cavity. First case was a primary lesion in the oral cavity, which showed distant metastatic deposits in liver, kidney, bone and brain. Histopathologically, lobules of pleomorphic clear cells were evident descending from the overlying mucosa, raising the suspicion of renal cell carcinoma. Immunohistochemical staining for CD10 was negative and the case was diagnosed as clear-cell type of oral squamous cell carcinoma which had disseminated to distant organs. In the second case, dysplastic clear granular cells were seen invading the bone. Immunohistochemical staining for CD10 showed focal mild positivity, confirming the diagnosis as clear-cell renal carcinoma which had metastasized to the oral cavity. Metastatic tumours must be considered in the differential diagnosis of rapidly growing ulcero proliferative lesions in the oral cavity.