[902] Role of Percutaneous Needle Core Biopsy in Diagnosis and Clinical Management of Renal Mass: Experience of a Single Institution

Rong Hu, Celina Montemayor-Garcia, Kasturi Das. University of Wisconsin, Madison, WI

Background: Renal needle core biopsies are routinely performed for diagnosis of renal masses. Accurate diagnosis can be challenging and the role of renal biopsy in management of kidney tumors is debatable. This is to report our experience in diagnostic accuracy of renal biopsy and its role in clinical management of renal masses based on a large cohort study.
Design: We identified 301 consecutive cases of renal biopsies performed for 280 renal masses from 269 patients in our institution between 2008 and 2011. Final pathology diagnosis, H&E and immunohistochemistry slides of renal biopsies and available subsequent nephrectomy specimens were reviewed. Clinical data were analyzed.
Results: The patients consisted of 74 women and 195 men with median age of 66 (18-92). 85% renal masses were incidental radiographic findings. 31 renal masses were nondiagnostic and 249 (89%) were diagnostic. Of the diagnostic masses, 58 were benign including 47 oncocytoma, 6 angiomyolipoma (AML) and 5 other benign lesions, 191 were malignant including 132 clear cell renal cell carcinoma (CCRCC), 22 urothelial cell carcinoma (UCC), 21 papillary renal cell carcinoma (PRCC), 5 unclassified renal cell carcinoma (U-RCC), 3 chromophobe RCC and 8 others. Subsequent nephrectomy diagnoses were available for 55 masses classified as malignant by biopsy, of which 51 had identical diagnosis as biopsy, 3 had change in histological subtype and 1 high grade carcinoma was subsequently diagnosed as UCC. Thus the diagnostic accuracy for renal biopsy was 100% in determining malignancy and 93% in determining accurate subtype. Follow-up was available for 208 diagnostic cases. There is significant difference in clinical management between different diagnostic groups (table 1).

Table 1. Clinical management of renal masses following biopsy diagnosis
 CCRCCPRCCUCCChromophobeU-RCCOther *Benign Lesion **
Nephrectomy39 (35%)1 (6%)13 (72%)1 (33%)2 (40%)1 (25%)1 (2%)
Chemo5 (4%)02 (11%)01 (20%)2 (50%)0
Ablation61 (54%)13 (76%)3 (17%)2 (67%)2 (40%)1 (25%)11 (23%)
Surveillance8 (7%)3 (18%)000036 (75%)
* includes metastasis and high grade carcinoma; ** includes 39 oncocytoma, 6 AML and 3 other benign lesions

Conclusions: Majority (85%) of renal masses are found incidentally. Percutaneous needle core biopsy provides diagnostic material in 89% of cases with 100% accuracy in determining malignancy and 93% accuracy in determining histologic subtype. Renal biopsy diagnosis has an impact on subsequent clinical management of renal masses.
Category: Genitourinary (including renal tumors)

Monday, March 4, 2013 9:00 AM

Proffered Papers: Section A, Monday Morning


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