Metastatic Tumors of the Oro-Facial Tissues: Clear Cell Renal Cell Carcinoma. A Clinico-Pathological and Immunohistochemical Study of Seven Cases

Metastases to orofacial tissues are infrequent, their incidence being 1-8% of malignant oral tumors, sometimes manifesting as the first clinical sign of an occult cancer. Renal cell carcinoma (RCC) is the second most common metastatic carcinoma to the oro-facial tissues, involving the jawbones, gingiva, oral mucosa, tongue or salivary glands. Also, RCC frequently displays a prominent clear cell component, which may predominate in the clear cell renal cell carcinoma subtype (CCRCC) and histologically mimic many other clear cell tumors, both benign and malignant, which can be epithelial (from keratinizing epithelia, cutaneous adnexa, salivary glands and odontogenic epithelium), melanocytic or mesenchymal in origin. In view of the necessity for prompt and accurate diagnosis of such unusual neoplasms, we report on the salient clinico-pathological features of 7 CCRCC metastatic to the oro-facial tissues, and highlight their immunohistochemical profile, to more accurately discriminate this neoplasm from other tumors of the oral cavity with a prominent clear cell component.