[838] Correlation between Fuhrman Grading in Percutaneous Needle Biopsy and Surgical Resection Specimens in Clear Cell Renal Carcinoma ≤ 4 cm in Size

L Fahim, A Finelli, P Ryan, M Jewett, J Kachura, AJ Evans. University Health Network, Toronto, Canada; Mount Sinai Hospital, Toronto, Canada

Background: Renal cell carcinoma (RCC) is the most common primary malignant tumor of kidney in adults, the vast majority of which (< 80%) are of conventional or clear cell (CC-RCC) type. The Fuhrman grade (FG), a 4-tier grading scheme based on nuclear features, is the reference histoprognostic grading system most widely used for CC-RCC.) The prognostic value of FG for patients with RCC has been well-characterized. Recently, percutaneous needle biopsy has gained popularity for establishing the diagnosis of incidentally detected small renal masses (SRM) < 4 cm in size. Since it is possible that this procedure may under-represent the true FG as a result of limited sampling, we compared FG between paired biopsy and subsequent resection specimens in a consecutive series of SRM CC-RCC cases.
Design: We identified 30 patients with SRM who underwent percutaneous biopsy showing CC-RCC between 2004 and 2009. All patients subsequently underwent partial or radical nephrectomy. The original slides from the biopsies and resection specimens were reviewed to determine the correlation between biopsy and final FG. If multiple FG were present in the same specimen, the highest FG was considered to be the overall FG.
Results: There were 11 female and 19 male patients. Median tumor size was 2.5 cm (range 1.4 - 4) and the median age at presentation was 58 years (range 32 - 78). The average time between biopsy and surgery was 3.7 months. There was exact agreement between biopsy and resection specimen FG in 29 of 30 cases (96%). Upon collapsing the FG system into either low grade (FG 1 and 2) or high grade (FG 3 and 4), we found 100% agreement between biopsy and resection FG. No cases showing heterogeneity with respect to low- and high-grade areas were identified in this SRM CC-RCC series.
Conclusions: Percutaneous renal tumor biopsies are safe, cost-effective and most often conclusive for histological diagnosis of SRM. Our experience indicates that percutaneous biopsy will provide highly accurate FG information for CC-RCC < 4 cm in size. This information may be critical in terms of choosing the optimal treatment for SRM CC-RCC that are incidentally detected, particularly in elderly or infirm patients where it may be desirable to avoid or delay surgical intervention.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 151, Tuesday Morning


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