[822] Frozen Section (FS) Analysis of Cancer Containing Bladder Transurethral Resection Specimens (TURB) for the Presence of Muscularis Propia (MP) Invasion.

Rajen Goyal, Shreenath Bishu, Vamsi Parimi, Ximing J Yang, Stephen M Rohan. Northwestern University Feinberg School of Medicine, Chicago, IL

Background: The use of FS for intra-operative consultation and management can be an extremely powerful tool. However, surgical pathologists are commonly confronted with specimen types which are not amenable to FS or clinical questions which can be better addressed on permanent section (PS). At our institution, we are frequently asked to assess TURB specimens at FS for the presence of MP invasion. Given the lack of studies in the literature addressing this specific issue it is difficult to make an evidence based argument against this practice. This study documents the experience of a single academic center in evaluating cancer containing TURB specimens at FS for MP invasion.
Design: Thirty-two cases of cancer containing TURB specimens sent for FS from 2008-2010 were identified in our files. The FS and PS diagnosis were reviewed for discrepancies in regards to the presence or absence of invasive carcinoma, tumor grade, and MP invasion. Cases that were excluded from the calculation of test performance included: 1) cases with FS diagnosis deferred 2) cases without muscularis propria on the FS and subsequent PS slides. The sensitivity (SEN), specificity (SPEC), positive predictive value (PPV), and negative predictive value (NPV) for identifying MP invasion at FS were then calculated.
Results: In 5 cases (16%) the FS diagnosis was deferred. In all of the remaining cases the FS diagnosis of carcinoma and the tumor grade was concordant with the PS diagnosis. In 7 cases MP was not present in the FS or the subsequent PS slides. Of the remaining 20 cases, 2 false positive and 6 false negative diagnoses of MP invasion were identified (60% concordance rate). The test performance for FS assessment of MP invasion in TURB were SEN = 45%, SPEC = 77%, PPV = 71%, and NPV = 53%.
Conclusions: The diagnosis of carcinoma and the tumor grade can be determined accurately on TURB specimens at FS. The diagnosis of MP invasion on PS can be difficult and our results suggest that this diagnosis is even more difficult at FS. Though this study is based on small numbers at one academic center, the results strongly point to the conclusion that the examination of TURB specimens for MP invasion is best done on PS. This conclusion is also supported by our experience that the FS diagnosis in TURB cases rarely, if ever, changes intraoperative management.
Category: Genitourinary (including renal tumors)

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 202, Tuesday Morning


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