Cutaneous metastases in renal cell carcinoma: a systematic review and a case report.

Objective: Cutaneous metastases of renal cell carcinoma (C.M.R.C.C.) are rare and associated with a poor prognosis. The aim of this study is to evaluate the incidence and the prognosis of C.M.R.C.C. with a relevant case report. Materials and methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (P.R.I.S.M.A.) of existing literature in English and Scandinavian languages was used in t​​he period 1902-2017 with a literature search in PubMed, Embase, and Cochrane Library. Results: Nine original articles were found where the incidence of a C.M.R.C.C. was 3.3% (168/5017). In order to estimate the prognosis of C.M.R.C.C., 161 articles were found with a total of 334 cases. Survival was described in 40% of all cases (132/334). In 31% (102/334) of the cases the final time of death was stated and in this group the mean survival was 10.9 months. Ninety-six per cent died within 36 months after being diagnosed with C.M.R.C.C. Conclusion: C.M.R.C.C. are rare with an incidence of 3.3%. The prognosis is poor with a high mortality. It is suggested that the skin should be examined in the diagnostic evaluation and follow-up for patients with renal cell carcinoma.