[Chromophobe cell renal cancer, a distinct entity. Report of a series of 35 cases]

To describe the clinical and histological characteristics and natural history of clear cell renal carcinoma.The case files of 35 patients (22 men and 13 women, with a mean age of 58 +/- 13.8 years) operated for clear cell renal carcinoma were reviewed. The circumstances of diagnosis and the histological features of the tumour were analysed. The outcome of the patients was studied with a mean follow-up of 70 +/- 20.2 months.The diagnosis was incidental in 66% of cases. The macroscopic appearance of the tumour was characteristic: homogeneous and beige or white colour. On light microscopy, tumours were composed of variable proportions of clear cells and eosinophilic cells. The were classified as 15 predominantly eosinophilic tumours (43%), 9 predominantly clear cell tumours (26%) and 11 tumours composed of equal number of clear cells and eosinophilic cells (31%). Nuclei were irregular and indented. Hale stain was positive in every case. The majority of tumours were confined to the kidney (T1: 65% and T2: 29%) with a low nuclear grade (91% of grades 1 and 2). No patient developed local recurrence or metastasis during follow-up. The overall 5-year survival rate was 92%. No death related to the disease was reported.The histological diagnosis of clear cell renal cancer is now easy and can be suggested even on macroscopic examination of the operative specimen. This tumour appears to have a good prognosis, as it is usually confined to the kidney with a low nuclear grade.