WHAT ARE THE DIFFERENT TYPES OF BIOPSY PROCEDURES?
A whole organ or a whole lump is removed (excised). These are less common now, since the development of fine needle aspiration (see below). Some types of tumors (such as lymphoma, a cancer of the lymphocyte blood cells) have to be examined whole to allow an accurate diagnosis, so enlarged lymph nodes are good candidates for excisional biopsies. Some surgeons prefer excisional biopsies of most breast lumps to ensure the greatest diagnostic accuracy. Some organs, such as the spleen, are dangerous to cut into without removing the whole organ, so excisional biopsies are preferred for these.
Only a portion of the lump is removed surgically. This type of biopsy is most commonly used for tumors of the soft tissues (muscle, fat, connective tissue) to distinguish benign conditions from malignant soft tissue tumors, called sarcomas.
This is probably the most commonly performed type of biopsy. It is done through a fiberoptic endoscope the doctor inserts into the gastrointestinal tract (alimentary tract endoscopy), urinary bladder (cystoscopy), abdominal cavity (laparoscopy), joint cavity (arthroscopy), mid-portion of the chest (mediastinoscopy), or trachea and bronchial system (laryngoscopy and bronchoscopy), either through a natural body orifice or a small surgical incision. The endoscopist can directly visualize an abnormal area on the lining of the organ in question and pinch off tiny bits of tissue with forceps attached to a long cable that runs inside the endoscope.
This is a gynecologic procedure that typically is used to evaluate a patient who has had an abnormal Pap smear. The colposcope is actually a close- focusing telescope that allows the physician to see in detail abnormal areas on the cervix of the uterus, so that a good representation of the abnormal area can be removed and sent to the pathologist.
Fine Needle Aspiration
(FNA) biopsy.This is an extremely simple technique that has been used in Sweden for decades but has only been developed widely in the US over the last ten years. A needle no wider than that typically used to give routine injections (about 22 gauge) is inserted into a lump (tumor), and a few tens to thousands of cells are drawn up (aspirated) into a syringe. These are smeared on a slide, stained, and examined under a microscope by the pathologist. A diagnosis can often be rendered in a few minutes. Tumors of deep, hard-to-get-to structures (pancreas, lung, and liver, for instance) are especially good candidates for FNA, as the only other way to sample them is with major surgery. Such FNA procedures are typically done by a radiologist under guidance by ultrasound or computed tomography (CT scan) and require no anesthesia, not even local anesthesia. Thyroid lumps are also excellent candidates for FNA.
This technique is typically used by dermatologists to sample skin rashes and small masses. After a local anesthetic is injected, a biopsy punch, which is basically a small (3 or 4 mm in diameter) version of a cookie cutter, is used to cut out a cylindrical piece of skin. The hole is typically closed with a suture and heals with minimal scarring.
Bone Marrow Biopsy
In cases of abnormal blood counts, such as unexplained anemia, high white cell count, and low platelet count, it is necessary to examine the cells of the bone marrow. In adults, the sample is usually taken from the pelvic bone, typically from the posterior superior iliac spine. This is the prominence of bone on either side of the pelvis underlying the "bikini dimples" on the lower back/upper buttocks. Hematologists do bone marrow biopsies all the time, but most internists and pathologists and many family practitioners are also trained to perform this procedure.
This part of procedure, the aspiration, is usually followed by the core biopsy, in which a slightly larger needle is used to extract core of bone. The calcium is removed from the bone to make it soft, the tissue is processed and tissue sections are made. Even though the core biopsy procedure involves a bigger needle, it is usually less painful than the aspiration.