Is There a Role for Renal Biopsy to Rule Out Sarcomatoid RCC Prior to Cytoreductive Nephrectomy?

A 67-year-old man was found to have a 10 cm left renal mass invading his spleen, the tail of his pancreas, colon, and abdominal wall musculature. Concomitant lung metastases are also identified. Patient's performance status has declined over the past several months. Your team is planning a renal mass biopsy to rule out sarcomatoid features prior to recommending cytoreductive nephrectomy.