Histopathologic Analysis Of Peritumoral Pseudocapsule And Surgical Margin Status After Tumor Enucleation For Renal Cell Carcinoma

Main Category: Urology / Nephrology
Also Included In: Cancer / Oncology
Article Date: 17 Oct 2008 - 3:00 PDT

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UroToday.com - The wide acceptance and approval of a surgical technique aiming to cure patients with RCC depends on the technical feasibility and excellent results reported in retrospective series [1-4], along with prospective confirmation on pathological examination of its oncological safety.

Our study confirmed that all renal cell carcinomas suitable for nephron-sparing surgery are surrounded by a continuous (not fenestrated) fibrous pseudocapsule, irrespective of tumor size, with a mean (range) pseudocapsule thickness of 0.39 (0.048-0.798) mm that does not correlate with tumor dimension. The tumor pseudocapsule can be penetrated irrespective of tumor size, with a reported infiltration rate of 26.6% on the parenchymal side and 6.6% on the perinephric adipose tissue side, but the presence of a thin layer of parenchymal tissue invariably allows for negative surgical margins, also if no efforts are made to leave a rim of healthy kidney tissue around the neoplasm[5]. This thin rim of normal parenchymal tissue, with signs of lymphoplasmocytic inflammation, is present as 'leopard spots' on the intact pseudocapsule, and it is always present in cases of neoplastic penetration of the pseudocapsule into the kidney tissue.

Therefore, the main conclusion to be drawn from our study is that if the surgeon follows the natural cleavage plane between tumor pseudocapsule and kidney parenchyma by blunt dissection, thus performing a tumor enucleation, there is no risk of positive surgical margins even with larger masses [5]. To always 'stay close to the tumor margin' surrounded by its pseudocapsule allows the surgeon to avoid entry into the tumor, and if the pseudocapsule is microscopically penetrated, a minimal layer of kidney tissue with a mean (range) thickness of 1.05 (0.38-1.60) mm invariably ensures negative surgical margins.

Our study clearly represents a rationale for adopting the tumor enucleation technique as the standard procedure for the excision of pT1a and pT1b renal cell carcinoma tumors.

References

1. Carini M, Minervini A, Masieri L, Lapini A, Serni S. Simple enucleation for the treatment of pT1a renal cell carcinoma: our 20-year experience. Eur Urol 2006; 50: 1263-1271.
2. Carini M, Minervini A, Lapini A, Masieri L, Serni S. Simple enucleation for the treatment of renal cell carcinoma between 4 and 7 cm in greatest dimension: progression and long-term survival. J Urol 2006; 175: 2022-2.
3. Pertia A and Managadze L. Long-term results of simple enucleation for the treatment of small renal cell carcinoma. International Braz J Urol 2006; 32(6): 640-647.
4. Kutikov A, VanArsdalen KN, Gershman B, et al. Enucleation of renal cell carcinoma with ablation of the tumour base. BJU Int 2008. Doi:10.111/j.1464-410X.2008.07661.x
5. Minervini A, Di Cristofano C, Lapini A, et al. Histopathological analysis of peritumoral pseudocapsule and surgical margins status after tumor enucleation for renal cell carcinoma. Eur Urol. In press. Doi:10.1016/j.eururo.2008.07.038.

Written by Andrea Minervini, MD, PhD, as part of Beyond the Abstract on UroToday.com

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