[Satellite intrarenal tumor nodules in renal carcinoma. Therapeutic implications]

To analyze the incidence of tumoral satellite nodules in renal carcinoma, study the main features of the primary tumor and establish an approach to determine the risk of multicentricity.

We analyzed 286 radical nephrectomies due to renal carcinoma. Twenty-nine cases (10.13%) that had intrarenal tumoral nodules were chosen; 5 cases (17.2%) had adenoma and 24(82.8%) had carcinoma. All but one case with von Hippel Lindau disease were sporadic tumors. The main features of the principal tumor (size, cellular type, architectural features, grade and stage) in both groups with and without nodules, were analyzed and compared.

The mean diameter was 7.89 +/- 4.091 cm (range 3.5-20) for the tumor and 0.85 +/- 0.65 cm (range 0.1-3) for the nodule. The mean tumor diameter was not significantly different from that of the group with no nodules (mean tumor diameter 8.16 +/- 3.58, range 2-25). Ten cases had only 1 nodule (34.48%), 4 had 2 (13.79%), 2 had 3 (6.89%), 3 had 4 (10.34%) and 10 had 5 or more nodules (34.48%). The mean age was 56.89 +/- 11.46 (range 22-76); 24 were males (82.75%) and 5 females (17.14%); 14 cases were located in the right (28.27%) and 15 in the left side (51.72%). The foregoing data were not significantly different from those of the group with no nodules. Nineteen cases had clear cell, 5 granular, 4 mixed and 1 had the fusiform cell type. Seventeen cases were grade 2 (68%) and 8 cases grade 3 (32%); there were no G1 or G4. Ten were Robson stage I (34.48%), 2 were stage II (6.89%), 11 stage III (37.93%) and 6 stage IV (20.68%). Three cases had local recurrence (10.34%). No differences were observed for survival between the two groups. A 3 cm nodule was diagnosed preoperatively in only one case. Assuming the following criteria of a localized tumor, stage I, with a diameter less than 5 cm for performing elective nephron-sparing surgery, only 8 of the 43 cases that met the foregoing criteria had nodules (16.18%). Of these, 4 (2 of which were adenomas) had a single nodule (9.3%). If the criterion of low grade (G1-G2) tumor is also considered, only 5 of the 27 cases that met the foregoing additional criterion had nodules (14.7%).

When nephron-sparing surgery is performed, it should be remembered that there is an approximately 10% risk of leaving tumor nodules of small size in the kidney which may cause local recurrence. Consequently, these patients should be followed very closely.