1Department of Internal Medicine, Matsuyama Shimin Hospital, 2The Third Department of Internal Medicine, Ehime University Medical School
Fine needle aspiration biopsy, Capsule of hepatoma, Experimental studies, Negative pressure
Echo aspiration biopsy was performed using a 21 G needle with a small diameter in 33 nodules of
intrahepatic small lesions. The biopsy tissue and resected specimen were compared in false negative cases.
Our results showed that when aspiration was initiated before the capsule in hepatoma cases with a thick
capsule, the needle tip was occluded with cirrhotic tissue and the capsule and tumor tissue did not enter
into the needle. Therefore, it is necessary for the needle to puncture the tumor before initiating aspiration
Regarding the fine needle aspiration biopsy, the performance capability of the needle itself and the
procedure for puncturing have been discussed much, whereas how the aspired specimens should be treated
has been little discussed. The specimens, when allowed to stand only for a second, become fragmented. We
note that the causes for such fragmentation includes an influx of air from the tip of the needle immediately
following the biopsy. In tissue sampling, even if consistent specimens are obtained, they are often found
to become fragmented by rapid influx of air from the tip of the needle. To prevent such fragmentation,
it is necessary to release negative pressure immediately following withdrawal of the needle. Our method
to release the negative pressure has proved to be very effective to ensure satisfactory aspired specimens.