Oral metastasis of renal cell carcinoma. Report of case and critical evaluation of morphologic features for differential diagnosis.

Two clear cell neoplastic lesions of the oral cavity, the first on the cheek and the second on the mucosa of the upper lip, were identified, in a 44 year old otherwise healthy man, 46 and 51 months after left nephrectomy for renal clear cell carcinoma. Basing on this case, unique for the double and limited metastasis of clear cell carcinoma of the kidney in the oral cavity, we discuss about the morphologic criteria usefull in the differential diagnosis of oral cavity clear cell tumors.