An atypical metastasis of renal clear cell carcinoma to the upper lip: a case report.

Metastatic lesions of the oral cavity are extremely rare, accounting for approximately 1% of all malignant oral tumors. Renal clear cell carcinoma (RCCC) constitutes about 3% of the solid tumors in adults. It is the third most frequent neoplasm to metastasize to the head and neck region, preceded by breast and lung carcinoma. Because of the silent growth of this neoplasm, most patients are asymptomatic and are diagnosed in an advanced stage, frequently with metastases. We report an unusual case of a 60-year-old male patient with an ulcerated nodule on the upper lip mimicking a keratoacanthoma. He was treated for left-sided RCCC 5 months earlier. The lesion was excised, and the histopathologic findings were suggestive of metastatic RCCC. The clinical features, prognosis, and treatment modalities for metastatic lesions are reviewed in our report. This case is a rarity because only 3 cases of metastatic RCCC of the upper lip have been reported in the literature.