[Early-onset sarcomatoid renal carcinoma. Report of a new case and comparison of the same case with another appearing at a mature age]. / Carcinoma renal sarcomatoide de temprana aparición. Aportación de un nuevo caso y comparación del mismo con otro de aparición en edad madura.

OBJECTIVE AND METHODS: We report two new cases of this rare and aggressive tumour; one case appeared in the earliest age reported in the literature (case #2). We also review etiological, diagnostic and therapeutic features. RESULTS: Despite aggressive surgery and adjuvant chemotherapy it has a very poor prognosis, with disease progression within 6 months in both cases. CONCLUSIONS: Sarcomatoid renal cell carcinoma is an infrequent entity, extremely aggressive and requires radical surgery at the time of diagnosis due to its advanced stage, although results are poor. It can also appear in young people with the same aggressiveness than in adult age.