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

Objective: To describe the clinical and histological characteristics and natural history of clear cell renal carcinoma.
Patients and Methods: 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.
Results: 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.
Conclusion: 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.