[887] Should Saved Interval Sections of Prostate Needle Biopsy (PNBx) Specimens Be Examined Microscopically?

EH Kerr, VL Dailey, WE Grizzle, O Hameed. University of Alabama at Birmingham, Birmingham, AL

Background: In addition to using multiple histologic levels to evaluate PNBx material, many pathologists cut and save interval unstained sections for potential analysis by immunohistochemistry (IHC); these are usually discarded if not utilized. It is unclear, however, whether additionally evaluating these saved interval sections has an impact on the final diagnosis especially in contemporary twelve-part PNBx specimens.
Design: A retrospective search of twelve-part PNBx specimens over a consecutive seven month period (02-09/08) was performed to identify cases where a diagnosis of prostatic adenocarcinoma (PC) was not made on any specimen part and saved interval sections were available. These sections were retrieved, stained with hematoxylin and eosin, and histologically evaluated independent from the original sections to identify any possible foci of atypia. Identified foci were further characterized by a genitourinary pathologist and, if PC was contemplated, by IHC. Subsequent to that, the original surgical pathology slides were then reviewed to determine whether the atypical foci were present and, if so, compare their linear extent and the number of atypical glands seen to those in the interval sections.
Results: Out of 149 consecutive PNBx cases, 36 met the inclusion criteria and had unstained sections available for at least one specimen part. These cases were originally diagnosed as benign (n=28), high grade prostatic intraepithelial neoplasia (n=5), or focal glandular atypia (n=3). Two to 75 slides were re-evaluated per case (mean=34.9) with 2 to 10 slides (mean=3.1) re-evaluated per specimen part. Overall, examination of 1258 newly-stained slides for 404 uniquely designated specimen parts revealed atypical glandular foci (1-16 glands; 0.03-0.47 mm in length) suspicious for PC in 4 (1%) cases. In 2 of these, PC was confirmed by IHC. Although atypical foci were present in at least a single original section, only one was originally reported as such. It was, however, better visualized in the saved interval sections due to the presence of more glands and greater linear extent.
Conclusions: Although examination of newly-stained saved interval sections of PNBx specimens can identify atypical, potentially carcinomatous, foci, such foci are not new as they are usually present in the original sections. These findings support the practice of examining only 3 levels of PNBx specimens and, in the absence of atypia, discarding unused saved interval sections.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 105, Tuesday Afternoon

 

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