[949] Accuracy, Clinical Impact and Limitations in Interpretation of CT Guided Needle Biopsy of Renal Masses

M Ramineni, ON Kryvenko, NS Gupta. Henry Ford Hospital, Detroit, MI

Background: With the advent of sophisticated imaging techniques, the detection rates of indeterminate masses in the kidney have increased in numbers. Pre-operative characterization of the tumor plays in important role in deciding between conservative management with minimally invasive procedures versus radical surgery. We evaluated the accuracy, impact and limitations of CT guided biopsy of renal masses.
Design: We retrospectively reviewed 82 biopsies performed at our hospital from 2005 to 2008 for indeterminate kidney lesions. Relevant data such as size of the tumor, location, and radiologic description, number of cores, pathologic diagnosis, and necessity for immunostains were recorded on the biopsies. All patients were followed-up and data on the type of treatment received, nephrectomy diagnosis, and location of the tumor, stage, Fuhrman grade, and metastasis were recorded.
Results: Biopsies were interpreted as clear cell renal cell carcinoma 13 (16%), papillary renal cell carcinoma 7 (9%), renal cell carcinoma, not further classified 14 (17%), oncocytic neoplasm (ON) 13 (16%) subdivided as favor oncocytomas 10 (12%) and inconclusive for chromophobe renal cell carcinoma/oncocytoma 3 (4%), renal cell carcinoma favor mucinous tubular and spindle cell tumor 1 (1%), malignant/carcinoma 7 (9%), metastatic carcinoma 2 (3%), lymphoma/leukemia 3 (4%), suspicious for malignancy 3 (4%), angiomyolipoma 2 (3%), benign non-neoplastic diagnosis including inflammation, fibrosis, hemorrhage and necrosis 17 (21%). 18 (22%) of these patients underwent nephrectomy, 5 (6%) received cryoablation, 2 (3%) received radio-frequency ablation, 17 (21%) were benign and required no therapy. All cases on nephrectomy showed renal cell carcinomas (RCC). All 11 cases (100%) diagnosed as RCC showed RCC on subsequent nephrectomy. Biopsy results on 5 (6%) cases were false negative. 2 were multilocular cystic RCC, 1 papillary RCC, 1 clear cell RCC and 1 sarcomatoid RCC. 1 case with repeat biopsy showed clear cell RCC. 2 cases classified as ON on biopsy showed RCC on nephrectomy.
Conclusions: CT guided biopsy for renal mass is reliable and accurate. It can impact clinical management of a renal mass and can help in avoiding nephrectomy. We did not observe any false positive results. Low rate of false negative results were observed but when correlated with high suspicion for malignancy on clinical and radiologic data, those patients received repeat biopsies and nephrectomies for management of the renal masses.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 150, Tuesday Morning

 

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