[435] Fluorescent In-Situ Hybridization as an Ancillary Test for Residual Biliary Brush Cytology Specimens

G Denice Smith, Brian T Collins, Evelyn V Gopez, Barbara E Chadwick. University of Utah, Salt Lake City, UT; ARUP Laboratories, Salt Lake City, UT; Washington University, Saint Louis, MO

Background: The use of fluorescence in situ hybridization, specifically the Urovysion® probe kit, as an adjunct to routine evaluation of bile duct brushing specimens (BDB) has been demonstrated to be valuable in establishing a diagnosis of malignancy. To evaluate the performance of Urovysion® FISH on residual BDB, we collected material from 32 patient samples for which a cytologic diagnosis had already been rendered and compared the performance of FISH to cytology.
Design: Material remaining after standard cytology preparation was collected from 28 BDB samples stored in PreservCyt® or CytoLyt®. Slides were prepared manually and de-identified. Residual material from three FNA specimens and one pleural fluid specimen was prepared similarly. UroVysion® FISH was performed as described in the UroVysion® package insert. UroVysion® probes detect four chromosomal aberrations by FISH, including polysomy for chromosomes 3, 7, and 17, and the homozygous deletion of 9p21. UroVysion® FISH-stained slides were scanned using BioView Duet™ and re-classified by a cytotechnologist and a pathologist, who were blinded to cytologic outcomes.
Results: Of the 28 BDB specimens, 7 were positive for polysomy (7/28), 2 showed isolated trisomy of chromosome 7 (2/28), 6 were unsatisfactory (6/28) and 13 were negative (13/28). Of the 7 FISH-positive cases, cytology results were positive for adenocarcinoma in 4 cases, atypical/suspicious in 2 cases and negative in one case. The 2 trisomy cases by FISH were both atypical/suspicious by cytology. Only one of the 13 negative FISH cases was positive by cytology. Negative FISH results were found in 5 cases that had atypical cytology and 2 that were suspicious by cytology. Five cases were negative by both FISH and cytology. Four additional non-BDB cases were evaluated, including 3 FNA samples and one pleural fluid sample. One case showed atypical cytology and showed polysomy by FISH. Of the remaining 3 cases, all were adenocarcinoma by cytology and 2 were positive for polysomy by FISH.
Conclusions: Residual material from BDB specimens processed for cytologic diagnosis can be used for ancillary testing to support or exclude a diagnosis of malignancy, increasing the utility of these limited quantity samples. This may be particularly useful where cytology is indeterminate. The significance of a positive FISH result and a negative cytology result should be further investigated.
Category: Cytopathology

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 67, Tuesday Morning

 

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