Second surgery for renal relapse after nephron sparing surgery: review of seven cases.

OBJECTIVE Anatomo-pathologic review of the cases which underwent a second surgery operation for a renal neoplasm relapsed after conservative surgery, in order to find possible relations with the surgical technique. PATIENTS AND METHODS At our institution nephron sparing surgery (NSS) is currently indicated for neoplasms smaller than 4 centimetres in diameter. The technique involves the removal of the neoplasm with a margin of healthy parenchyma and with the perilesional fat. Patients are firstly monitored by a CT check after 4 months and then with ultrasound/CT checks every 6 months in the first 2 years and then once a year In this study we analyze in the 1994-2005 period the records of cases undergoing a second operation for a renal tumour relapsed in the operated kidney after NSS. All specimens were reviewed by an individual experienced uro-pathologist who determined the size of surgical margins and relations between the site of the recidivism and the site of the preceding NSS procedure. RESULTS Seven cases with renal relapse have been found out of 267 undergoing conservative surgery in the same period (incidence 2.6%). The diagnosis has always been made in the lack of other localizations of disease at a complete re-staging and the average latency of the relapse was 19.4 months (8-46 months). In 5 cases the second tumour has been found in the site of the previous NSS: for these cases the minimum margin of the enucleo-resection was lower then 3 millimetres (median minimum margin 1.6 mm). Differently, in the remaining 2 cases, both with a wider surgical margin (median minimum margin 12.0 mm), the site of thefirst and that of the second neoplasm were distant. In particular, in one case a multifocal recidivism with a spread microvascular embolisation has been found, while in the other the primary neoplasms and the relapse presented a different histotype. CONCLUSIONS In the 5 cases with a narrow resection margin and relapsing tumour in the site of the enucleo-resection one can hypothise the persistence of a peritumoral microscopic neoplastic disease. In the other 2 cases with a wider surgical margin the relapse can be attributed to the widespread microscopic multifocality in one case and to the development of a second de novo neoplasm in the other one. The extension of the surgical margin seems then to have played a role in determining a relapse in the site of enucleo-resection.