[892] SNP Microarray Analysis Assists with Diagnosis of Renal Epithelial Tumors

Heidi H Hamilton, Anne M McDermott, M Timothy Smith, Daynna J Wolff. Medical University of South Carolina, Charleston, SC

Background: The histologic overlap and immunohistochemical variability of renal epithelial tumors makes classification and diagnosis difficult. With significant prognostic and treatment implications, efforts to make the proper diagnosis are necessary. SNP microarray analysis has been proposed to be an ancillary study for the classification of renal epithelial tumors; however, its practical use in the day-to-day clinical setting as a supplementary tool has not been explored.
Design: All surgical pathology cases that were classified histologically as subtypes of renal epithelial tumors and had concurrent SNP microarray were retrospectively reviewed to correlate tumor morphology, immunohistochemical characteristics, and SNP microarray results.
Results: Of the forty-one cases reviewed, thirty-three (80%) had concordant histologic and microarray results. Three cases were unclassifiable by microarray due to unique chromosomal abnormalities. Five of the forty-one cases (12%) had discordant microarray and histologic diagnoses. One discordant case was diagnosed histologically as renal cell carcinoma with clear cell and papillary features while the microarray result was consistent with papillary renal cell carcinoma. One case was originally diagnosed as clear cell renal cell carcinoma based solely on morphology; however, following review of the microarray results, immunohistochemical stains were performed, and the histologic diagnosis was changed to chromophobe renal cell carcinoma. Three cases were consistent with oncocytoma by SNP microarray but were diagnosed as a subtype of renal cell carcinoma based on morphology, immunohistochemistry, and the potential impact that the diagnosis had on patient follow-up.
Conclusions: With confusing and sometimes overlapping morphology among the renal epithelial tumors, SNP microarray can be used in routine clinical care as an ancillary study in the classification of these neoplasms. At our institution, the diagnosis of renal epithelial tumors is influenced by but not dependent on the concurrent microarray results. Although the final diagnosis was not consistently altered, microarray results prompted further consideration with confirmatory studies such as immunohistochemistry as well as provoked additional communication with the clinicians to provide the best patient care.
Category: Genitourinary (including renal tumors)

Monday, March 4, 2013 1:00 PM

Poster Session II # 166, Monday Afternoon

 

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