Two years after surgical removal of a renal cell carcinoma, a 70-year-old male patient developed generalized erythroderma and diffuse alopecia within a few days, which could not be further classified as a definite entity. The clinical picture showed well circumscribed roundish areas free of erythema, simulating normal skin (" nappes claires"). The skin disease was found to be resistant to systemic corticosteroids and oral retinoids, whereas in the laboratory work-up multiple lung metastases of the renal cell carcinoma were shown by computer tomography. The clinical picture and the course of the disease suggested a close relationship to the metastasizing visceral tumour, and the erythroderma was seen as a cutaneous marker of the internal neoplasia. A therapeutic trial with recombined interferon alpha-2a led to complete healing of the erythroderma within a few weeks and long-lasting stabilization of the metastasizing visceral tumour over 18 months.