Role of Percutaneous Renal Biopsy in the Evaluation of Renal Masses – The Cleveland Clinic Experience.
Manju Aron, Ming Zhou. Cleveland Clinic, OH
Background: Percutaneous renal biopsy is a safe and reliable diagnostic tool in the diagnosis of unresectable renal cell carcinoma, metastatic masses and lymphoma. With the increase in the detection of incidental small renal masses (SRM's) and the use of ablative therapies in a select patient population, needle biopsy is evolving as a reliable tool for histopathological evaluation, directing patient management. We assessed the role of percutaneous renal biopsies in the evaluation of renal masses at the Cleveland Clinic from Jan 2007 to Aug 2010
Design: Renal biopsies performed for the primary diagnosis of renal masses from Jan 2007- August 2010 were retrieved from the histopathology files. Data pertaining to the biopsy indication, size of the mass, patient demographics, and the biopsy and resection specimen results were recorded and analyzed
Results: Biopsies from 136 cases were studied. The age range of the patients was 35-91 years with 85 males and 51 females. The size of the masses ranged from 0.5 cm to 22 cm, and 65 (48%) were small renal masses (≤ 4 cm, SRM). 24 cases had multiple masses of which 14 were bilateral. Resection specimens were available in 28 cases. Immunohistochemicl stains (IHC) were performed in 57 cases.
Table1. shows the distribution of the cases and the biopsy results. A tumor diagnosis was possible in 95.6% of the cases while it was non diagnostic in 4.4%. The tumor was classifiable on morphology alone in 55.8% of the cases, but with addition of IHC a total of 78.7% cases could be classified. 16.9% of the cases however could not be further classified. The addition of IHC increased the classifiable tumors in the SRM's significantly more than in the large tumors(87.7% vs 70.4%, p=0.001).
|Tumor size ≤4 cm||Tumor size >4 cm||Total|
|Number of cases||65||71||136|
|Non-diagnostic||4 (6.1%)||2 (2.8%)||6 (4.4%)|
|Tumor diagnosis||61 (94%)||69 (97.2%)||130 (95.6%)|
|Tumor, classifiable*||57 (87.7%)||50 (70.4%)||107 (78.7%)|
|Tumor, unclassifiable*||4 (6.1%)||19 (26.8%)||23 (16.9%)|