[790] Venous Perfusion Optimizes the Fixation and Evaluation of the Renal Vasculature and Parenchyma in Nephrectomy Specimens

A Bhalodia, SM Bonsib. Louisiana State University Health Science Center, Shreveport, LA

Background: The importance of renal sinus fat and venous invasion in renal cell carcinoma (RCC) resulted in its inclusion in the 2002 TNM staging system. Retraction and collapse of the veins after surgery can make the gross recognition of the sinus vein (SV) involvement difficult. This study evaluates the practicality and effectiveness of a venous perfusion (VP) technique for examining nephrectomies for SV invasion in RCC.
Design: The venous systems of 13 nephrectomies and 2 autopsy kidneys were examined. The 13 nephrectomies included 8 papillary, 5 clear cell, 1 renal medullary, and 1 pelvic urothelial carcinoma (2 cases contained 2 tumors). The renal arteries and veins were exposed, 60cc of formalin was injected into the renal artery and vein, followed by a perfusion of formalin under hydrostatic pressure into the main renal vein (MRV) for 4 -16 hrs. In 3 cases, prior to VP, a 1 cm slice of cortex was immersion fixed (IF) as an internal control for comparison with VP. Following VP, the nephrectomy specimens and autopsy kidneys were handled in a standard fashion.
Results: VP is easy and can be completed within 15 min. Grossly, the perfused veins from the MRV to its intralobular tributaries were fixed in an open position permitting visualization of internal surfaces and entering branch veins of 1-2 mm size.

The renal cortex appeared well fixed (pale). However, the renal pyramids were less well-fixed (reddish). Histologically, there was a marked difference between IF and VP fixed cortex. The tubules of IF cortex were eosinophilic and compressed, the interstitum scant, and veins often collapsed. The tubules of VP cortex were less eosinophilic, had open lumens, the interstitium expanded and the veins open compared to IF cortex.
Conclusions: 1) Venous perfusion is a practical approach to specimen fixation that adds little additional handling time. 2) VP markedly enhances the direct inspection of the venous system for intravenous tumor. 3) VP results in markedly improved histology compared to IF. 4) VP facilitates gross recognition of important sinus vein staging features in nephrectomy specimens.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 166, Tuesday Morning

 

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