Scalp metastases of a renal cell carcinoma.

An 80-year-old man presented with a localized tumor of the right occipital scalp. The tumor was a 1-cm, bright red-purple, ulcerated, and crusted exophytic nodule on a smooth base (Figure 1). The lesion had grown asymptomatically over 18 months except for profuse bleeding induced by minimal trauma. It was extirpated with the clinical diagnosis of pyogenic granuloma vs. renal metastasis to the scalp. The patient's medical history included a transurethral prostatic resection 3 years earlier and, 1 year later, a right nephrectomy for a 2-kg kidney tumor verbally reported as "benign." The patient also had a 2-year history of untreated high blood pressure. Histopathologically, the excised tissue was an exo-endophytic nodule of a solid form composed of pleomorphic neoplastic cells with abundant clear cytoplasm, surrounded by fibrous collagen septae, blood vessel proliferation, and areas of hemorrhage (Figures 2 and 3). The histopathologic diagnosis of metastatic renal cell carcinoma was supported by immunohistochemistry with positive epithelial membrane antigen staining (Figure 4). Cytokeratins 7 and 20 were nonreactive. Laboratory studies revealed hematuria and elevated creatinine and urea nitrogen levels, but no malignant cells were observed in five urinary cytologies. Renal ultrasound showed the presence of two simple cysts in the left kidney and data compatible with chronic inflammatory disease.