Biliary Tract Malignancy, FISH Only
Assessing bile duct brushing or hepatobiliary brushing specimens for malignancy
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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.
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 and bile aspirate specimens is superior to that of conventional cytology.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
An interpretive report will be provided.
The chance that the patient has cancer is calculated based on the following parameters: patient age, FISH results (negative, trisomy, polysomy), and primary sclerosing cholangitis (PSC) status (non-PSC versus PSC patient). This information is then provided in the interpretive portion of the final report.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
A positive FISH result does not identify location or type of malignancy; cytology and biopsy may help clarify such situations.
Bile duct brushing and bile aspirate specimens were collected from 303 patients at the time of endoscopic retrograde cholangiopancreatography (ERCP). Cytological specimens from these patients were evaluated for malignancy with FISH and exfoliative cytology. Among patients with malignancy on follow-up, the sensitivity of FISH was superior to cytology (44% versus 15%, P<0.001). The specificity of FISH and cytology were similar (98% versus 100%, P=0.250).
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Kipp BR, Stadheim LM, Halling SA, et al: A comparison of routine cytology and fluorescence in situ hybridization for the detection of malignant bile duct strictures. Am J Gastroenterol 2004 September;99(9):1675-1681
2. Moreno Luna LE, Kipp BR, Halling KC, et al: Advanced cytologic techniques for the detection of malignant pancreatobiliary strictures. Gastroenterology 2006 October;131(4):1064-1072
3. Barr Fritcher EG, Kipp BR, Slezak JM, et al: Correlating routine cytology, quantitative nuclear morphometry by digital image analysis, and genetic alterations by fluorescence in situ hybridization to assess the sensitivity of cytology for detecting pancreatobiliary tract malignancy. Am J Clin Pathol 2007 August;128(2):272-279