Fine needle aspiration biopsy is an inexpensive and rapid method of establishing the diagnosis of lesions and masses in various organs. It has advantages over other forms of biopsy because it is safe, rapid, reliable and relatively painless. This technique can be used to sample superficial and subcutaneous lesions in breast, thyroid, lymph node, salivary gland and superficial abdominal masses. It can also be used in deep visceral lesions with the help of radiologists using fluoroscopy, computer assisted tomography, angiography and ultrasonography to localize the lesions.
Technique: Proper clinical history is helpful in establishing diagnosis. To avoid any mishap during procedure, the patient should be explained and assured about the procedure. A disposable syringe with 21-25-gauge needle can be used for this purpose (5-10 ml). The area is cleaned thoroughly with a spirit swab. The needle is introduced into the mass negative pressure is applied by retracting the plunger and mass is probed in several directions. Prior to withdrawal of needle, the plunger is released allowing equalization of pressure. A cotton swab is applied for few min to stop the bleeding.
Purpose of FNA Biopsy:
- FNA biopsy is primarily used to diagnose and evaluate abnormalities, particularly in cases where cancer is suspected.
- It helps determine the nature of a lump, nodule, or mass, distinguishing between benign (non-cancerous) and malignant (cancerous) growths.
- FNA can be performed in various parts of the body, including the thyroid, breast, lymph nodes, salivary glands, and internal organs.
- Patient Preparation: Before the procedure, patients are often briefed about the process. In some cases, local anesthesia may be administered to numb the area for comfort.
- Needle Insertion: During FNA, a thin, hollow needle is inserted into the suspicious area through the skin. The choice of needle gauge depends on the location and size of the lesion.
- Sample Aspiration: The needle is then used to aspirate (withdraw) cells or tissue from the lesion. Multiple aspirations may be made to ensure an adequate sample is obtained.
- Sample Preparation: Once collected, the sample is placed on a glass slide or in a fixative solution for preservation.
- Pathologist Examination:The collected cells or tissue are examined under a microscope by a pathologist to make a diagnosis.
After aspiration the syringe is detached from the needle and filled with air. The syringe is reattached to the same needle and plunger is pushed to gently express the material onto glass slides. This step is repeated once or twice. The material is gently spread on the slides by using another slide. Some people use opposite surfaces of the two slides (one slide containing aspirated material and another clean slide) for smearing. The slides are allowed to air dry or fixed wet in solution containing ether and alcohol in equal proportions or 95% alcohol. The slides can be stained by Papanicolaou (PAP), Hematoxylin and Eosin (H&E), Leishman and modified Giemsa stains.
If the specimen is too bloody, the cells from the actual lesion will be diluted in the smear. If the aspiration time is too long the specimen will clot in the syringe and needle and therefore will not be expelled or spread properly. If slides are incorrectly made, the nuclear details will be poor and artefacts created.
Advantages of FNA Biopsy:
- Minimally Invasive: FNA is less invasive than traditional surgical biopsies, resulting in less pain, scarring, and a shorter recovery period.
- Speed and Convenience: FNA can be performed quickly, often on an outpatient basis, with same-day results in some cases.
- Accuracy: It provides accurate information about the nature of the lesion, aiding in the planning of further treatment or monitoring.
The major complications of aspiration biopsy of superficial lesions are bleeding and infection. In cases of deep-seated lesions pneumothorax, embolism, neurovascular injury, internal major bleeding or intraperitoneal leak of hollow viscus has been reported. Vasovagal syncope may also occur. Tumor spread along the needle tract has been reported following biopsy with large bore needles. However, there is no evidence that aspiration using fine needles increases the risk of tumor dissemination. Those individuals who do the procedure often and are experienced in the method should perform this procedure. They may be pathologists, surgeons or radiologists.
Conditions Diagnosed with FNA:
- Thyroid Nodules: FNA is commonly used to assess thyroid nodules and distinguish between benign and malignant growths.
- Breast Lumps: It helps diagnose breast lumps and evaluate whether they are cancerous or non-cancerous.
- Lymph Nodes: FNA assists in evaluating swollen or abnormal lymph nodes for signs of infection or cancer.
- Salivary Glands: It is used to assess salivary gland masses for tumors or infections.
- Organ Masses: FNA can be employed to examine masses in various internal organs, such as the liver, kidneys, and pancreas.