Multifocality of renal cell tumors is a factor to consider before performing a partial nephrectomy

We conducted a retrospective analysis of radical nephrectomies performed in our clinic in order to evaluate the incidence of multifocality in relation to the stage, grade, size and histological type.

Preoperative imaging studies and the final pathological results of surgical specimens were reviewed. Separate primary tumors at a distance of more than one cm from the primary tumor were counted. Of 56 renal cell cancers 10 (17.8%) were multifocal. Of these 10, 3 were found with primary tumors less than or equal to 4 cm, while 7 were found with tumors between 4-10 cm. Three multiflocal tumors were found with TI tumors, none with T2, 4 with T3a and three with T3b primary tumors. Six cases were present where the histological subtype of the largest tumor was clear cell, while 4 had mixed cell histology. No multifocality was observed in the 4 grade I tumors, while 3 of the 32 grade II tumors and 6 of the 20 grade III tumors were multifocal. The only grade IV tumor presented with a separate primary tumor. Statistically significant correlation was found between multifocality and tumor grade stage and clear cell histology subtype. There was no correlation between the primary tumor size and the possibility of multifocality.

Although partial nephrectomies are justified from their survival rates, close follow-up is necessary because separate primary tumors may still exist in the kidney, left behind, irrespective of tumor size.