Fine Needle Aspiration

A method to biopsy, obtain cells, for examination under the microsope.

FNA, performed in conjunction with a CT or MRI imaging, enables pathologists to determine the nature of a suspicious biliary tract abnormality.

Procedure:

It is a surprisingly safe procedure that involves passing a small needle directly through the skin or through an endoscope. The CT or MRI imaging allows the doctor to see where the needle is going. This is because the needle used has a very small bore. This sometimes means that the small amount of tissue obtained is insufficient for the pathologist to establish a diagnosis.

Accuracy:

A diagnosis of biliary cancer based on a FNA is highly accurate, approaching 99%. However, it is only between 50-70% accurate in determining whether the cancer is benign or malignant.

Because the amount of tissue obtained is so small, the absence of malignant cells in the sample cannot exclude the possibility of malignant disease altogether.

Risks:

Complications such as bleeding or infection occur very rarely, less than 1% of patients.

Another technique used to obtain cells from the biliary tree for examination is bile duct brushing. In this procedure, through an endoscope, a brush is used to remove cells from the inside of the bile duct. These cells are smeared onto a slide and examined under the microscope.