Diagnostic accuracy and clinical impact of renal biopsy cytology

Background: The role of fine needle biopsy cytology in the workup of renal mass lesions remains controversial. With advances in imaging technology and clinical management for renal masses, a critical reevaluation of the role of renal biopsy is needed. This study was designed to provide a comprehensive evaluation of the performance and clinical impact of fine needle biopsy in patients with renal masses. Methods: A 5-year retrospective study of ultrasound or computer tomography (CT)-guided fine needle biopsies of renal masses diagnosed via cytopathology was conducted. Overall diagnostic rate, sensitivity, and diagnostic accuracy were calculated. Further analysis of the impact of fine needle biopsy cytology on clinical management was performed. Results: A total of 227 cases of fine-needle aspiration and/or biopsy (FNA/B) of renal masses were identified, including 76 with subsequent nephrectomies. Complications were rare (<1%). The diagnostic rate and sensitivity of FNA/B were 83.3% and 89.5%, respectively. Diagnostic accuracy was 98.7% at the major categorical level and 94.7% at the tumor subtype level. Subsequent clinical actions were associated with a definitive cytologic diagnosis of malignancy/neoplasia (p < .05) and were affected by tumor subtype (p < .05). Conclusion: This study demonstrates that FNA/B of renal masses is a safe and reliable minimally invasive diagnostic tool with excellent accuracy in confirmation of malignancy and subclassification of tumors. Diagnoses made on FNA/B play a key role in guiding a personalized clinical treatment plan.