To present our experience with laparoscopic partial nephrectomy (LPN) in patients with an incidentally detected Stage pT2, pT3a, or pT3b renal mass.

Of 525 patients undergoing LPN, 21 (4%) had pT2 or worse disease. LPN routinely involved en bloc excision of the overlying perirenal fat, along with the tumor and a healthy parenchymal margin. The preoperative computed tomography scans of these 21 patients were reviewed again by an unblinded radiologist to determine whether any suspicious radiologic signs of clinical Stage T2 or worse disease were present.

The tumors were Stage pT2 in 1 (0.2%), pT3a in 19 (3.6%), and pT3b in 1 (0.2%). The mean pathologic tumor size was 3.7 cm (range 1.8 to 7.4). In the patient with pT3b disease, a tumor thrombus invading a renal vein branch was detected laparoscopically. The renal parenchymal and perirenal fat surgical margins were negative for cancer in all 21 patients (100%). The repeated nonblinded review of the preoperative computed tomography scans suggested definitive evidence, equivocal evidence, and no evidence of pT3a disease in 0, 5 (26%), and 14 (74%) patients, respectively, and suspicion for pT3b disease in the 1 patient. One patient with a 2.5-cm pT3a sarcomatoid renal cell carcinoma with negative surgical margins developed distant metastasis and died. During a mean follow-up of 29 months (range 1 to 58), the cancer-specific survival rate was 95%.

The results of our study have demonstrated that adherence to surgical principles allows LPN to be performed for occult Stage pT2 and pT3 tumors with negative surgical margins and good oncologic outcomes. We have highlighted the importance of routine en bloc laparoscopic excision of the overlying perirenal fat along with the tumor, and intact specimen extraction, mirroring open surgery.