Management of patients with renal mass lesions based on renal biopsy cytology results.

The benefit of renal biopsy, especially in patients with a history of malignancy (HOM), has not been well-studied. We studied the clinical management of 339 renal masses after fine needle aspirate and/or core needle biopsy with touch preparation. Forty-one percent of patients had HOM, which did not increase the incidence of renal malignancy. The main reasons for renal biopsy were HOM and small renal masses (≤3 cm). The most common renal masses were clear cell renal cell carcinoma (32%). Thirty percent of renal masses metastasized. The overall accuracy of renal biopsy for subclassification was 76%. Nephrectomy was selected to manage 41% of renal masses, most for primary renal carcinoma. Chemoradiation was selected to treat 15% of patients, especially those with lymphoma (93%), metastatic malignancy (93%), and urothelial carcinoma (69%). Ablation was used to treat 6% of patients. Active surveillance was selected for 34% of patients, predominantly those with benign condition. Our results showed that renal biopsy was an easy and less aggressive tool for obtaining adequate diagnostic materials to render reliable and accurate diagnoses. Initial renal biopsy prevented unnecessary nephrectomy in patients with diagnoses of metastatic malignancy, lymphoma, and most benign tumors/lesions (for most but not all cases). Renal biopsy avoided chemoradiation against prior HOM in patients with diagnosis of benign tumors/lesions (22% of all patients) and primary renal carcinoma (38%). Therefore, renal biopsy significantly impacts the management of patients with renal mass, and any questionable renal mass should be biopsied before further management.