26537 Biliary Tract Malignancy, FISH (BILAO)

​Assessing bile duct brushing or hepatobiliary brushing specimens for malignancy

​When this test is ordered, fluorescence in situ hybridization testing will be performed. When additional specimens are received, the laboratory will add BILOB to the second specimen, BILOC to the third specimen, and so on.

1. If performing local cytology in addition to fluorescence in situ hybridization testing, aliquot half of the specimen into another ThinPrep vial before processing the specimen.

2.  Submission of residual specimen (after processing other testing) may compromise the sensitivity of the test.

3.  Label each specimen with specific source (eg, right hepatic duct or common bile duct).

​A positive fluorescence in situ hybridization (FISH) result does not identify location or type of malignancy. FISH abnormalities may be associated with high-grade dysplasia or carcinoma in situ. Cytology and biopsy may help clarify such situations.

Endoscopic retrograde cholangiopancreatography (ERCP) is used to examine patients with biliary tract obstruction or stricture for possible malignancy. Biopsies and cytologic specimens are obtained at the time of ERCP. Cytologic analysis complements biopsy by sometimes detecting malignancy in patients with a negative biopsy. Nonetheless, a number of studies suggest that the overall sensitivity of bile duct brushing and bile aspirate cytology is quite low.

Fluorescence in situ hybridization (FISH) is a technique that utilizes fluorescently labeled DNA probes to examine cells for chromosomal alterations. FISH can be used to detect cells with chromosomal changes (eg, aneuploidy) that are indicative of malignancy. Studies in our laboratory indicate that the sensitivity of FISH to detect malignant cells in biliary brush specimens is superior to that of conventional cytology.

No abnormality detected by fluorescence in situ hybridization

​An ​interpretive report will be provided.