Fine needle aspiration is a clinical procedure performed to look for signs of cancer, infection, and other types of disease in suspicious masses of body tissue. A long, thin needle is inserted into a suspected tumor, and a tiny sample of fluid and tissue are extracted. Laboratory analysis of the tissue can help doctors confirm or rule out different medical conditions. In most cases, fine needle aspiration can be performed in a matter of minutes in an outpatient surgical clinic or hospital.
When an unusual mass or lump is discovered during a physical exam or diagnostic imaging scans, a doctor usually decides to arrange for fine needle aspiration. Palpable lumps in the lymph nodes of the neck, head, breast, and groin are the most common sites for aspiration tests, but a physician may decide to perform the procedure on a mass elsewhere on the body if it is near the skin and suspicious-looking. Fine needle biopsies are almost always preferred over more invasive surgical procedures since the risk of infection and other complications is much lower.
Before the procedure, a specialist thoroughly sterilizes the skin above the mass and marks an injection point. Most fine needle aspirations are done without anesthesia, but a doctor may decide to apply a local anesthetic if the skin is tender or the patient is nervous about the needle. The hollow needle punctures the skin and enters the center of the lump. A tiny sample of cells is drawn through the needle into a sterile syringe. The doctor then carefully removes the needle, applies pressure to the puncture wound to control any bleeding, and bandages the wound with gauze and adhesive.
The sample collected by fine needle aspiration is transferred to a sterile laboratory slide so it can be analyzed under a microscope. A pathologist studies the sample to check for signs of cancer, inflammation, and infection. After a diagnosis is confirmed, a team of doctors can begin considering different treatment options.
In addition to being an important diagnostic procedure, fine needle aspiration can also be helpful in gauging the success of treatment procedures. A doctor can perform an aspiration after attempting to treat a tumor with radiation and chemotherapy, and compare the collected tissue to the sample gathered before treatment. If the new sample is cancer-free or shows signs of expiring cancer, the doctor can be sure that treatment was effective.