[905] Intravenous pT3 Renal Cell Carcinoma: The Challenge of Gross Recognition.

Kunle O Ojemakinde, Cynthia X Zhao, Ami Bhalodia, Stephen M Bonsib. Louisiana State University Health Sciences Center, Shreveport

Background: Extrarenal extension of renal cell carcinoma (RCC) is usually by intravenous (IV) routes, renal sinus veins (SV), main renal vein (MRV) or retrograde into cortical veins (CV). Determination of primary tumor (PT) size requires distinguishing renal-limited disease from IV extension. This study examines the accuracy of gross evaluation for IV extension.
Design: Photographs of 28 RCCs with/without IV invasion were given to 10 pathologists instructed to outline PT with a pen but exclude SV, MRV, CV. These were compared to control photos marked by 2 authors (SMB and AB) who had examined all cases. Pathologists were divided into 5 faculty with 3-25 yrs. experience and 5 trainees (PGY4 residents/fellows). Correctly outlined PT were tabulated and analyzed by Fisher's exact test and p-values calculated.
Results: Twenty-eight photos marked by 10 pathologists resulted in 280 observations. All pathologists (50/50) correctly marked pT1/T2 PT. Substantial errors occurred with pT3 IV tumors with inclusion of IV tumor as PT (Fig1-correct; Fig2-IV included as PT). Only 70/230 pT3 tumors were correctly marked. Faculty correctly marked 23/130 pT3 PT. Trainees correctly marked 47/130 pT3 PT.

Distribution of the properly identified Primary Tumors.

pT-Stage	# Photograph Cases	Trainees = 5	Faculty = 5	p-Value.
pT1/2	5	100%	100%	NS
pT3-SV	5	40%	36%	1.0
pT3-SV+CV	8	35%	20%	0.21
pT3-MRV+SV	1	40%	20%	1.0
pT3-MRV+SV+CV	9	47%	11%	0.0004
Total pT3	23	40.9%	20.0%	0.0009

Conclusions: 1) Pathologists correctly identify pT1/2 but often misinterpret pT3 IV RCC. 2) Trainees out performed faculty attributed to training by SMB and AB. 3) Tumor size may be over estimated and pT3 tumors understaged if prosectors are not trained in recognizing IV extension. 4) The importance of tumor size is lost if inaccurate gross evaluation is widespread.
Category: Genitourinary (including renal tumors)

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 118, Monday Morning