Fine needle aspiration biopsy of renal cell carcinoma: Cytologic parameters and their concordance with histology and flow cytometric data

Fine needle aspiration biopsy (FNAB) is increasingly utilized in the initial diagnosis of renal neoplasms. Nuclear grading assessment, however, has not been applied routinely to these neoplasms, and data on its validity are lacking. To determine the reproducibility and clinicopathologic significance of Fuhrman's nuclear grading (FNG) on FNAB specimens, we retrospectively analyzed cytologic and histologic tissues from 49 cases of renal cell carcinomas (RCC). Our data indicate a high concordance between nuclear grading in FNA material and histologic specimens (80-92%). Moreover, interobserver and intraobserver reproducibility was high (89-92% and 86-96%, respectively). The flow cytometric DNA content of 13 specimens (65%) yielded DNA diploidy in five cases (38%) and DNA aneuploidy in eight cases (62%). All eight DNA aneuploid neoplasms were FNG 3 (7 cases) and 4 (1 case), while two of the four DNA diploid neoplasms manifested FNG 3. We conclude that cytologic nuclear grading of RCC correlates with corresponding grading of histologic specimens and could be performed reproducibly for clinical use.