[Clinical-pathological study of incidental renal cell carcinoma]

To determine the percentage of renal cell carcinomas incidentally diagnosed (IRCC) and to compare their clinical and pathological characteristics with symptomatic or non-incidentally diagnosed tumors (SRCC).

We retrospectively study 189 patients who were diagnosed of renal carcinoma between 1990 and 1999. 166 underwent surgery (149 radical nephrectomy; 17 nephron-sparing surgery). We determine the percentage of IRCC detected by radiological tests and compare them with the SRCC diagnosed after presenting with some of the classic symptoms or metastasis, with special focus on tumor size, pathology stage, tumor recurrence, progression and evolution.

87 SRCC (46%); 102 SRCC (54%). There are not differences in terms of age, gender, side, and postoperative hospital stay. Tumor size was higher in the SRCC (mean 8.5 cm) than in the IRCC (6.3 cm). SRCC tumor stage was: pT1 27.3%, pT2 27.3%, pT3a 23.8%, pT3b 16.6%, pT3c 2.3%, and pT4 2.3%; IRCC stage was: pT1 51.3%, pT2 25.6%, pT3a 10.9%, pT3b 10.9%, pT3c 1.2%, and no pT4. The percentage of patients with lymph node involvement was higher (p = 0.02) in the SRCC (15%) than in the IRCC (4.8%). The percentage of patients with metastasis at the time of diagnosis was higher in the SRCC group (26%) than in the IRCC (9.2%). Recurrences were more frequent in the SRCC Group (8.3%) than in the IRCC (1.2%) (p = 0.07). Tumor progression was more frequent in the SRCC group (34%) than in the IRCC (7.3%) (p<0.01). 76% of the patients undergoing nephron sparing surgery were IRCC.

Currently, there is a high percentage of IRCC (46% in our series from 1990-99). Renal tumors presenting as IRCC have better prognosis, since they have significantly smaller size, lower stage, less advanced disease, less recurrences, and less progression than SRCC.