Lingual metastasis as an initial presentation of renal cell carcinoma.

Distant metastasis of malignant neoplasm to the oral soft tissue is extremely rare. We report a case of renal cell carcinoma (RCC) metastasizing to the tongue. A 47-year-old man visited our hospital with chief complaint of a lump on the middle third of the dorsum of his tongue and the lesion fell off from the tongue. Although histopathological diagnosis of the mass was granuloma teleangiectaticum, similar nodule reappeared in the same area 2 weeks later. The second lesion was composed of granuloma teleangiectaticum and aggregation of neoplastic clear cells in ductal arrangement. The clear cells were immunohistochemically positive for EMA and CD10. The abdominal CT scan revealed a 5.5 cm mass in the left kidney, suggesting RCC. Thus, the lingual lesion was consistent with metastatic RCC. There has been no recurrence for 2 years after the radical nephrectomy and local excision of the tongue.