Comparison of Specimen Processing Methods for Biliary/Hepatic Duct Brush Specimen FISH Interpretation.
Heather S Currens, Lynne A Meltesen, Carolyn E Jarrett, Stephen S Raab. University of Colorado, Aurora
Background: FISH (fluorescence in situ hybridization) is increasingly being used in conjunction with routine cytology on biliary/hepatic duct brushing specimens for increased sensitivity in the diagnosis of cholangiocarcinoma and ductal dysplasia. For FISH specimens to be adequately analyzed a preparation must be made that presents the cellular component without overlap of cell groups. The aim of this study was to establish a standardized process for FISH preparations of consistent, diagnostic quality.
Design: Various processing methods were utilized to process biliary duct brushing and hepatic duct brushing specimens (n=45) in order evaluate signal interpretability in FISH. FISH assay evaluated abnormalities on chromosomes 3, 7, 17 and 9p21 (UroVysion, ™ Abbott Laboratories). Biliary duct/hepatic duct brushings collected endoscopically were submitted in CytoLyt ® for routine cytology as well as FISH. Different processing techniques included: Shandon Cytospin® (Thermo Fisher Scientific) preparations (n=6); air-dried smears (n=4); cell block specimens (n=4); ThinPrep® (Hologic™) specimens (n=5) and ThinPrep® specimens (n=26) preceded by a blending step (Waring Blender™). The overall success and failure of the various processing modalities was examined.
Results: Cytospin® preparations were diagnostic in three cases (50.0%). Overlapping of cells made the signal evaluation problematic. Four specimens (100%) processed as air-dried direct smears failed due to lack of adequate cellularity. One ThinPrep® specimen (17.0%) failed due to cellular overlap. Four specimens from formalin-fixed cell block material (100%) failed for insufficient material. Twenty-six specimens blended with a Waring Blender® for 20 seconds prior to ThinPrep® processing (100%) were successfully processed for FISH.
Conclusions: The characteristic properties of biliary /hepatic duct brushing specimens are problematic in creating a mono-layer preparation for FISH preparations.Teasing the cellular material from the endoscopic brush results in flecks or strings of tissue that when processed using the ThinPrep® processor often creates cellular overlap. To reduce this clumping of cellular material we have found that a brief (20 second) blending of the specimen in a laboratory issue Waring Blender® breaks up the cellular clumps without distorting the cellular morphology or affecting the results of FISH.
Tuesday, March 1, 2011 9:30 AM
Poster Session III # 72, Tuesday Morning