Intrarenal satellites of renal cell carcinoma: Histopathologic manifestation and clinical implication

Objectives: This study was designed to gain more insight into the incidence of satellites of renal cell carcinoma related to the pathologic stage and grade of the primary tumor. Methods: One hundred eight nephrectomized kidneys with renal cell carcinoma were sectioned at 3-mm intervals and inspected microscopically for satellite carcinomas. The number, site, size, and distance of satellite carcinomas found were recorded in relation to the primary carcinoma. Results: The overall incidence of satellite carcinoma was 6.5% (7 of 108). The incidence of satellite carcinoma in relation to the pathologic staging of the primary tumor was 7.1 % (1 of 14) in pT1, 3.0% (2 of 66) in pT2, and 14.3% (4 of 28) in pT3. The incidence was higher in patients with N1 disease (25%) than in those with NO (5.0%), and higher in M1 disease (25%) than in those in MO (5.77%). There was no relationship between the grade and multicentricity. Conclusions: The incidence of satellite carcinoma was higher in cases with high-stage primary carcinoma. However, even in localized diseases (pT1, pT2), satellite carcinomas were found at a 3.75% incidence. When nephron-sparing surgery is indicated in low-stage cases, precise clinical staging using a combination of various imaging modalities is mandatory, with intraoperative ultrasonography being one possible modality for detecting a concomitant satellite carcinoma.