IPLC was not associated with more favorable tumor biology (lower pGS, better tumor stage) and not influenced by patient conditions (age, body mass index, American Society of Anesthesiologists score, smoking) or intraoperative parameters (blood loss, operating time, surgeon). In addition, there was no significant correlation with serious complications (Clavien-Dindo Grade 3a/b) within a period of 90 days.

In the present series of consecutive patients undergoing RARP there was no evidence for a more aggressive tumour biology or a higher complication rate in obese patients.

Bilateral oncocytosis along with multiple tumours in both kidneys represents a very rare pathology that is accompanied by diagnostic and therapeutic challenges. We report the case of a 60-year old male patient who underwent computer tomography with incidental detection of multiple bilateral and contrast enhancing renal tumours of different size. Subsequently the patient underwent nephron-sparing tumor resection, first on the right side and 4 weeks later on the left side. The histology of all removed tumors showed evidence of pure oncocytoma. There were no postoperative complications and renal function reached a stable state within 6 months follow-up. The major challenge regarding diagnostic process and therapy of this pathology is to distinguish benign oncocytoma from chromophobe renal cell carcinoma and hybrid tumours, which can all be associated with renal oncocytosis. Because of limitations concerning imaging processes and biopsy, all patients should undergo nephron-sparing surgery as far as possible. On the other hand alternative therapies should - regarding to therapy-associated morbidity and the basically benign prognosis of oncocytoma - be well discussed to obtain informed consent. In this case report different therapy options and the international literature concerning renal oncocytosis will be discussed.