Metastatic renal-cell carcinoma presenting as a cutaneous horn.

Renal-cell carcinoma develops as an insidious neoplasm, frequently metastasizing to the skin. Cutaneous manifestations vary regarding morphology and sites of predilection. A patient was recently seen demonstrating a metastasis from a renal neoplasm. The lesion was unusual in that it grossly resembled a cutaneous horn. Dermatologists should continue to be alert to the possibility of renal tumor metastasis when evaluating cutaneous tumors.