[Incidental renal carcinoma]

The increasing use of progressive noninvasive diagnostic imaging techniques, has substantially increased the detection of incidentally detected renal cell carcinoma (RCC).

To determine the manner of presentation of RCC and the frequency of incidentally detected RCC. The natural history of RCC of incidentally discovered RCC was compared with that of symptomatic RCC, the reasons for examination and the methods of diagnosis in patients with incidental tumours were analysed.

In a retrospective study, 463 patients with RCC treated between 1981 and 1995 were reviewed. The patients were divided into four groups according to the fact as to whether the tumours were diagnosed on the basis of urologic symptoms, with paraneoplastic syndromes, with symptoms of metastatic disease, or whether they were detected incidentally. The records of 180 patients with RCC treated between 1991 and 1995 were grouped according to the fact as to whether the tumour was detected incidentally (n = 85), or whether it was discovered with symptoms related to the neoplastic renal disease (n = 95). The groups were compared regarding patient's age, sex, tumour size, grade of malignancy, stage and survival using univariate analyses.

The number of RCC detected incidentally has increased from 9.3% (1981-1985) to 47.2% (1991-1995). There were significant differences between groups in the distribution of clinical stages, T1 + T2 stages were more frequently detected in incidental tumours (p < or = 0.005). No significant difference was observed between the survival of incidental and symptomatic patients. Abdominal ultrasonography was the most useful method for the detection of incidental RCC (88.2%).

The results of this study suggest that the incidentally detected RCC occur in lower stages than the symptomatic tumours.