Types of Biopsy
Many types of biopsy exist. The primary physician, radiologist, surgeon or other physician will determine the most appropriate method of biopsy and guidance based on various factors including:
- the tissue, organ or body part to be sampled
- how suspicious the abnormality appears
- the size, shape and other characteristics of the abnormality
- the location of the abnormality
- the number of abnormalities
- other medical conditions a patient may have
- the preference of the patient, and
- the imaging and biopsy systems available at a given hospital or healthcare location
Biopsies are usually guided by the method that identifies the abnormality best. Palpable lumps can be felt and therefore no additional guidance is needed in most cases. Lesions discovered by an imaging test, for example, mammography or CT, will often need biopsy that is guided by the modality that shows the lesion the best. For example, CT is usually the method of choice for imaging the lungs, so CT imaging is used to guide most lung biopsies. If an abnormality is seen well on multiple imaging tests, the modality that provides the safest, most accurate, fastest and/or least expensive route will be used to guide the biopsy. Lesions discovered by a screening test such as PSA may require blind sampling biopsy since there is often no focal visible or palpable abnormality to target.
Aspiration or FNA Biopsy is performed with a fine needle attached to a syringe. Aspiration biopsy is often referred to as Fine Needle Aspiration (FNA). FNA biopsy is a percutaneous (through the skin) biopsy. FNA biopsy is typically accomplished with a fine gauge needle (22 gauge or 25 gauge). The FNA procedure is often performed, for example, to diagnose nonpalpable breast abnormalities (Learn more about FNA on the breast). FNA may be performed under image guidance such as ultrasound. The area is first cleansed and then usually numbed with a local anesthetic. The needle is placed into the region of the abnormality such as a cyst or tumor. Once the needle is placed, a vacuum is created with the syringe and multiple in and out needle motions are performed. The cells to be sampled are sucked into the syringe through the fine needle. Three or four samples are usually taken.
Before microscopic examination is made, the sample of fluid and cells is sometimes spun at high speed in a centrifuge (a device for separating substances in a liquid by spinning the mixture at high speeds) then a small amount is placed on a slide and covered with a plastic slip. A smear is prepared by spreading samples of fluid and cells onto glass slides. The specimens are then fixed (preserved) and stained to improve viewing. The preservation (fixing) is often performed by heating the slide with a Bunsen burner or by using a methanol solution. A cytologist (pathologist who examines cells) then uses a microscope to examine individual cells for abnormalities, paying particular attention to the size, shape and structure of the cell and cell nucleus.
Tumors of deep, hard-to-get-to structures such as the pancreas, lung, and liver are good candidates for FNA. Such FNA procedures are typically done by a radiologist under guidance by ultrasound or computed tomography (CT) imaging and usually require no anesthesia or only local anesthesia. Thyroid abnormalities are also excellent candidates for FNA.
Cone Biopsy removes a piece of tissue which is cylindrical or cone shaped. Cone biopsy is performed to diagnose cervical cancer. Cone biopsy is often done following a pap smear, colposcopy (examination of the cervix under illuminated magnification), and a punch biopsy.
After the tissue is removed, it is analyzed in the pathology laboratory to determine whether cancer is present. Cone biopsy may also be performed as a treatment if a cancer is small enough to be completely removed during biopsy. There are two main methods used to perform cone biopsy. The LEEP (also called LLETZ) method, short for loop electrosurgical excision procedure, removes the tissue by using a wire that is heated by an electrical current. Patients are given local anesthesia and the procedure can be performed quickly in a physician's office. Another method of cone biopsy involves using a surgical scalpel or laser to remove the tissue. This procedure typically requires general anesthesia and may be performed in a hospital or outpatient facility. However, an overnight hospital stay is not usually required.
The most common side effects of cone biopsy include cramping/discomfort and moderate or mild bleeding for a few weeks after the procedure. Patients should avoid sexual intercourse, tampons, and douching until the incision is completely healed, which may take several weeks. Patients should also discuss other possible side effects of cone biopsy prior to the procedure.
The advantages of cone biopsy are that it provides a large sample of tissue for analysis and it can sometimes completely remove the cancer so the patient does not need additional surgery. However, because complications from cone biopsy are possible, women should discuss all aspects of the procedure with their physician before undergoing biopsy. If a cone biopsy is recommended after abnormal Pap smear results, a patient may wish to ask if a colposcopy (looking at the cervix with magnification) or cervical biopsy would be an appropriate alternative for her (if they have not already been performed), based on her individual case.