EUS-Guided FNA

What is EUS-Guided Fine Needle Aspiration (EUS-FNA)?

When doctors wish to examine a lump or mass that is underneath the skin, they perform a procedure called a FNA to biopsy that area. A lump that is just below the skin is referred to as superficial. Often they are easy to biopsy. In this procedure, a very small hollow needle is inserted into the area that needs to be examined. The hollow needle collects tissue that can be extracted and examined by a pathologist

If the mass that needs to be examined is too deep, or too close to a vital organ or blood vessel, obtaining a biopsy specimen can be difficult, and may require surgery. Another technique is to use endoscopic ultrasound (EUS) if the area that needs to be examined can be done endoscopically.

During an EUS-FNA, a flexible endoscope is inserted into the patient's body —usually after having been put to sleep— either through the mouth or the anus. The tip of the endoscope has a small rotating ultrasound system that can peer about four inches into surrounding tissue.

When inserted orally, the endoscope can examine in and/or around the esophagus, stomach, duodenum, and liver, as well as some of the pancreas. If inserted anally, the examination focuses in and around the colon and rectum.

When the site that needs to be biopsied has been located, a fine needle is inserted down a canal in the endoscope and inserted into the area that needs to be examined. Several samples of tissue are retrieved and examined by a pathologist who is often in the room during the procedure. The doctor may take several samples in different areas of the mass until a determination is made by the pathologist as to its nature.


You will be given specific instructions in order to prepare for this procedure, including:

  • when you can eat or drink
  • what medications you need to continue, or discontinue

You need to make sure you doctor is aware of:

  • all medications you are taking
  • other health conditions such as diabetes or heart trouble


EUS-guided FNA is a well-documented procedure that has few complications. Minor to moderate complications may include:

You may experience some discomfort following this procedure, but this often goes away in a few days. Serious complications are rarely reported, but may include:

Generally considered a safe, reliable diagnostic procedure, some studies have indicated the possibility of development of a pancreatic pseudocyst after an EUS-FNA ... but this is rare.