Isolated Nail Dystrophy: An Unlikely Presentation of Metastatic Renal Cell Carcinoma.

Metastasis of any malignancy to the nail unit is uncommon, and only a handful of cases of subungual renal cell carcinoma (RCC) metastasis have been reported. We describe a case of isolated nail dystrophy that proved to be the presenting symptom of a previously undetected RCC. In a patient presenting with a subungual lesion, tumor metastasis to the nail unit should be included in the clinical differential diagnosis in both oncology patients and previously cancer-free individuals, as a subungual metastasis may be the first indication of a clinically silent visceral malignancy.