[Sarcomatoid renal carcinoma]

Sarcomatoid carcinoma of the kidney is a unique, uncommon variety of parenchymatous tumors and is considered to have a worse prognosis by stage than the other histological types. Our experience is reviewed and compared with the larger series reported in the literature.

Of 101 cases of renal carcinoma submitted to surgery at our department from January, 1990 to December, 1996, there were 4 cases of sarcomatoid carcinoma of the kidney. We compared our cases with the larger series (91 cases in total) reported in the literature for incidence, age, distribution according to sex, tumor size, location, form of presentation, stage and survival.

Sarcomatoid renal carcinoma accounts for 1% to 6% of parenchymatous tumors of the kidney according to the different series. The mean age at presentation was 48 years (range 27-61) in our series; there was no prevalence according to sex or location; the renal capsule was not compromised in 3 out of the 4 cases; only one case showed regional lymph node involvement and no case showed distant metastasis at the time of diagnosis. Although these tumors are diagnosed in the advanced stages, two of our cases were incidentally discovered in the early stages (one died 13 months thereafter and the other is alive at 42 months). Patients that are alive and disease-free can only be found in the patient group with stage I or II tumor. All patients with tumor stage III and IV have died. This histological type has a worse prognosis. Most of the series report a mean survival of 5 months.

Sarcomatoid renal carcinoma accounts for 1%-6% of all renal carcinomas. It can present at any age and has a very poor prognosis, with a mean survival of 6 months.