A pathological study for multifocal tumors and infiltration of tumor pseudo-capsule of renal cancer

Abstract

Objective To explore the safe and effective width of a healthy parenchymal surgical margin in nephron-sparing surgery (NSS) for renal cell carcinoma. Methods From October, 2005to October, 2008, 131 renal carcinoma specimens (103 cases performed by radical nephrectomy and 28 cases by NSS) were studied. The tissue materials were taken at the site of pseudo-capsule, 3, 5, 10,15 mm laterally from the tumor edge respectively and HE staining. Specimens were examined grossly and microscopically for multifocal tumors, infiltration of tumor pseudo-capsule and other pathological features. The correlation between the renal tumor size and the pathological features were analyzed statistically. Results There were 131 specimens of renal carcinoma. In 61 cases with tumor diameter ＜4 cm, no case (0.0%) had multifocal tumors and infiltration of tumor pseudo-capsule. In 46 cases with tumor diameter 4-7 cm, multifocal tumors were found in 3 cases (6.5%), and infiltration of tumor pseudo-capsule was found in 2 cases. Among the 46 cases there was 1 collecting duct cancer accompanied with distant metastasis and renal vein tumor embolus. In 24 cases with tumor diameter ＞7cm, multifocal tumors were found in 4 cases (16. 7%) and infiltration of tumor pseudo-capsule was found in 3 cases. Four cases (16.7%) had renal vein tumor embolus. Two cases (8.3%) had distant metastasis. The renal tumor size was apparently associated with multifocal tumors and infiltration of tumor pseudo-capsule (P＜0. 05). Conclusions Mini-margin NSS, even simple enucleoresection, is a safe and effective approach for treating localized renal tumor of ＜4 cm. For carefully selected patients with tumor 4-7 cm, NSS is reasonable and feasible. But for the patient with tumor ＞7 cm,NSS is not recommended. Key words: Kidney neoplasms; Pathology; Nephron-sparing surgery