Cytomorphologic and molecular characterization of metastatic renal cell carcinoma diagnosed by fine-needle biopsy: a single-institution study.

Lymph nodes (n = 45), lung (n = 23), and pancreas (n = 20) were the most frequent metastatic sites sampled.

Progression varied by grade, with grade 4 clear cell RCCs metastasizing rapidly (mean 1.5 years) while lower-grade tumors showed prolonged latency.

VHL was the most frequently altered gene (n = 13), followed by PBRM1 (n = 7), BAP1 (n = 4), and CDKN2A loss (n = 4).

Additional notable alterations included NF2, SMAD4, SMARCB1, and FAT3.