Reliability of Aspiration Biopsy Cytology in the Grading of Renal Adenocarcinoma

Abstract

Needle aspiration biopsy and histologic samples were taken from three corresponding regions of the surgical specimens immediately after nephrectomy from 150 renal parenchymal tumours. At review 144 of these were diagnosed as adenocarcinomas and 6 as oncocytomas. The adenocarcinomas were classified into three grades according to the degree of differentiation: High, moderate, poor. The grade, as evaluated on cytologic grounds, was in agreement with the histologic grade in 75.9% of the cases and in disagreement by one grade in 24.1%. The cytologic assessment was undergraded in 19.1% and over-graded in 5.0%. The 5-year survival rate for patients with histologically highly differentiated carcinomas was 82.7%, for moderately differentiated 48.7% and for poorly differentiated 28.1%. For corresponding cytologic groups the survival rates were 72.7%, 49.9% and 22.2%. The grade was variable in the same tumour in 24.2% of the cases. The assessment demands several samples, from which the least differentiated is significant. The prognostic significance of needle aspiration biopsy is reliable when cytologic differentiation is poor, but declines as the differentiation improves.