Fine Needle Aspiration (FNA)
The FNA is a test that removes cells from the tumor, so that the pathologist can examine the slide with cells and make a diagnosis. FNA rarely disrupts the capsule of the tumor, so tumor “spillage” with FNA is not a common occurrence.
In the hands of a good pathologist, the FNA is reliable over 90% of the time; however, there can be some problems with it, such as:
- FNA can misdiagnose a malignant tumor as benign and give a false sense of security, or even lead to a delay in treatment.
- FNA can misdiagnose a benign tumor as malignant and cause unnecessary concern.
- FNA can inflame the tumor and make it more difficult to remove.
- The FNA could cause irritation, bleeding, and infection in the tumor.
There are some physicians who always perform FNA on parotid tumors, some do it if the tumor is behaving as malignant, and some physicians rarely perform FNA. The decision often depends on the quality of their pathologist to reliably interpret parotid FNA, or on the quality of their pathologist to interpret parotid tissue pathology at the time of the operation (frozen section pathology).
During a FNA, it is possible that the needle could miss the tumor because it is not always possible for a physician to feel the tumor. In those circumstances, it is best to have a FNA in conjunction with an imaging study, such as an ultrasound, to make sure that the needle is getting into the tumor.