The Utility and Diagnostic Accuracy of Ureteroscopic Biopsy in Diagnosing Upper Urinary Tract Urothelial Carcinoma
Vishal Vashistha, Debra L Zynger. The Ohio State University Medical Center, Columbus, OH
Background: Ureteroscopic biopsies of the ureter, renal pelvis, and ureteropelvic junction (UPJ) have become more pervasive for the diagnosis of upper urinary tract lesions. Tissue obtained from these locations is often minute and can be difficult to histologically evaluate. Our aim was to assess the accuracy of endoscopically obtained biopsies of the ureter, renal pelvis, and UPJ.
Design: Pathology and surgical procedural reports for all patients who had undergone upper urinary tract biopsies at our institution from 2008 to 2011 were retrospectively reviewed. We recorded the specimen clinical history, tissue size, and pathological stage and grade. The initial biopsy diagnosis was compared to the procedural surgical impression and follow-up pathology. Diagnoses that were discordant with follow-up pathology were re-reviewed and immunohistochemically analyzed using ki67, CD44s, CK20, and p53. Initial biopsy tumor stage and grade were compared to subsequent nephroureterectomy or ureterectomy specimens. Differences between tissue sizes were evaluated using a t-test.
Results: Ureteroscopic biopsies (n=83) had a sensitivity of 85.7% for the ureter (n=58), 87.5% for the renal pelvis (n=23), and 100% for the UPJ (n=2). No false positives were identified, with a specificity of 100% for all 3 locations. 8 cases were considered false negatives. After histologic re-review and immunostaining, only 1 of the false negative samples suggested diagnostic error yielding a diagnostic accuracy of 98.8%. The remaining 7 false negatives did not contain tumor and were therefore falsely negative due to insufficient sampling. The mean size was 0.8 cm for true positives, 0.3 cm for true negatives, and 0.6 cm for false negatives with a statistically significant difference between true positives and true negatives (p=0.001). 30 patients underwent surgical resection, with 23 (76.6%) having tumor in the initial biopsy. Comparing grade of the initial biopsy and resection, 82.6% (19/23) had concordant grade (grade higher in resection, n=3; grade lower in resection, n=1). A comparison of the stage identified 57.9% (11/19) with concordant stages (stage higher in resection, n=8).
Conclusions: Endoscopic biopsy is sensitive and specific for diagnosing malignancies of the upper urinary tract. The majority of errors are due to insufficient tissue sampling; consequently, performing immunostains does not provide further diagnostic information.
Category: Genitourinary (including renal tumors)
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 152, Wednesday Afternoon