Abstract
In a patient with malignancy confined to the upper or lower pole of kidney, nephron sparing surgery can be performed by isolating and ligating the segmental arterial branch while allowing unimpaired perfusion to rest of the kidney from the main renal artery.1
We report a case of a 65 year old male, with a past history of radical nephrectomy who developed asynchronous renal cell carcinoma in his solitary kidney and underwent in-situ nephron sparing surgery.

Introduction

Recent interest in partial nephrectomy or nephron sparing surgery for renal cell carcinoma has been stimulated by advances in renal imaging, improved surgical techniques and good long-term dialysis free survival in-patients undergoing this form of treatment. Partial nephrectomy necessitates complete resection of tumour with adequate margin and leaving behind optimum functioning parenchyma. It is indicated in-patients with bilateral tumours, solitary kidney and the small circumscribed polar tumours. With increasing number of small tumours being picked up incidentally during imaging, and often in younger patients with longer life expectancy, this form of parenchyma preserving surgery is being increasingly advocated.

Case Report

A 65 year old male presented with a right renal mass, detected during a surveillance health check up. He denied history of loss of weight, loss of appetite, fever or bone pains. He had undergone left radical nephrectomy seven years ago for renal cell carcinoma, clear cell type. The tumour had not involved the left renal vein, inferior vena cava, or perinephric fat. There was no metastatic lymphadenopathy. His postoperative period was uneventful and he was at present in good general health.

The present spiral CT scan abdomen-pelvis showed right upper and mid poles hypovascular, minimally necrotic mass lesion with mild posterior renal capsular invasion. MR renal angiography showing heterogeneous mass lesion within the upper and mid pole region with a single renal artery branching at the renal hilum. The right kidney was explored through 11-rib approach. The tumour mass was seen to occupy upper pole, anterior and posterolateral part of middle lobe. Lower lobe was free of gross tumour. Upper pole branch of renal artery was clamped after cooling the kidney with ice slush. In-situ nephron sparing right heminephrectomy was done. Frozen section examination revealed uninvolved surgical margins. The cut margin of the kidney was sutured over surgicel using vicryl 00.

Gross examination of the specimen revealed a multifocal tumour presenting as three bright yellow, soft masses with intervening normal renal parenchyma (Fig. 5). Histopathological examination showed Clear Cell Renal Cell Carcinoma, Nuclear grade 2, Robsons sage I. The surgical margin, renal capsule and renal vessels were free of tumour involvement. The postoperative period was uneventful, and he had satisfactory renal function.

Fig. 1 : CT scan showing right upper and mid-pole mass lesion in kidney.	Fig. 2 : MR renal angiography showing heterogeneous mass lesion within the upper and mid pole region with single renal artery branching at renal hilum.
Fig. 3 : Photograph showing rapaired renal margin over surgicel after partial Nephrectomy.	Fig. 4 : Cut surface of kidney revealing a multifocal tumour presenting as three bright yellow soft nodules.

Discussion

Renal cell carcinomas account for 3% of all adult malignancies2 and are a family of carcinomas arising from the renal tubules. Of the various subtypes, Clear cell carcinoma accounts for 75% of all renal cell carcinomas,3 the others being Papillary RCC, Chromophobe RCC and Collecting duct RCC. These different carcinomas have different and distinct morphological features and biological behaviour, linked to distinct genetic lesions. Clear cell RCC invariably shows loss of genetic material in 3p. Papillary RCC shows gain of genetic material i.e.; trisomy or tetrasomy of 7 or 17. Chromophobe RCC shows loss of multiple chromosomes. Each of these genetically distinct subtypes has distinct macroscopic and microscopic appearances and they differ in their biological behaviour. Most epidemiological studies have not separated these categories and the characteristics of Renal cell carcinoma are those of the dominant subtype, Vis a Vis, Clear cell renal cell Carcinoma.

RCCs can be Sporadic or Hereditary. The hereditary tumours are of Four types, VHL Disease, Hereditary papillary RCC, Hereditary non-papillary RCC and Hereditary Oncocytoma. The hereditary tumours have germ line mutations, are more often bilateral, multifocal and arise at a younger age. While Sporadic tumours have somatic mutations, are more often bilateral, multifocal and arise later in life.

The mainstay of therapy for RCC remains Surgery. These tumours are resistant to Radiotherapy and Chemotherapy Faithful to their origin as renal tubular cells, they often overexpress p -glycoprotein. This protein is responsible for drug efflux from the cell, leading to decrease intracellular concentrations and therefore reduced activity of drugs including chemotherapeutic drugs.

In a study done by Rabbani et al⁴ the incidence of metachronous contralateral Renal cell carcinoma was constant on long term follow up suggesting that surveillance of contralateral kidney should be rigorous and continued beyond 10 years of follow up.

Conclusion

Incidental early pickup of small size renal cell carcinoma due to widespread imaging in the population has increased the incidence of the various settings where nephron-sparing surgery can be offered to patients. The recognition that RCC is a family of genetically and biologically distinct tumours is new. Most epidemiological studies have not separated these categories and the characteristics attributed to the disease are those of the numerically dominant tumour i.e. the clear cell renal cell carcinoma.

Detection of germ line mutations in multifocal or bilateral tumours could help detect affected families, whose members can then be put under increased surveillance for early detection of tumour development. Nephron sparing surgery should be advocated in such patients in view of the increased susceptibility to multifocality, bilateral tumour development and longer life expectancy in these relatively younger patients.

Acknowledgement

I am grateful to Mr. Vaibhav Dicholkar (Librarian, Lilavati Hospital) for his continuous help in preparing this report.

References

1. Novick C. Partial nephrectomy, Andre Glenn’s urologic surgery, 6. 51-3.
2. Andrew C, Novick et al. Renal tumours, Campbell’s urology, 8 edition, 2685-710.
3. W. Marston linehan et al. Cancer of kidney and ureter, Principles and practice of Oncology, 6 edition, 1362-71.
4. Rabbani Farhang, et al. Temporal change in risk of metwchronous contralateral renal cell carcinoma; influence of tumour characteristics and demographic factors; 2370 J Clinical Oncology, 10/03/04.

*Resident of DNB Urology; **Consultant Histopathologist; *** Professor and Head of Genitourinary Oncosurgery; Lilavati Hospital and Research Centre, Bandra (W), Mumbai - 400 050, India.