A biopsy is the taking of a small body tissue sample from the suspected area to examine it very closely under a microscope.
Types of biopsies
1. Excisional biopsy
- This type of biopsy involves the removal (excision) of an entire organ or lump.
- These are less common now, since the development of fine needle aspirations (see below).
- Some types of tumors (such as lymphoma - a cancer of the lymphocyte blood cells) have to be examined as a whole, to allow for an accurate diagnosis. Hence, 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 completely removing it, so excisional biopsies are also preferred in such cases.
2. Incisional biopsy
- An incisional biopsy involves only a portional surgical removal of the lump.
- 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.
3. Endoscopic biopsy
- The endoscopic biopsy is probably the most commonly performed type of biopsy.
- It is done through a fiber optic endoscope that the doctor inserts into the body 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.
4. Colposcopic biopsy
- This is a gynecologic procedure that is typically used to evaluate patients who have abnormal Pap smear results.
- The colposcope is actually a close-focusing telescope that allows the physician to see, in detail, abnormal areas on the cervix of the uterus.
5. Fine needle aspiration (FNA)
- The FNA is another type of biopsy that is an extremely simple technique.
- A needle no wider than that typically used to give routine injections is inserted into a lump (tumor), where tens to thousands of cells are drawn up (aspirated) into a syringe.
- These cells are smeared on a slide, stained, and examined under a microscope by the pathologist.
- A diagnosis can often be rendered within minutes.
- umors of deep, hard-to-get-to organs (pancreas, lung, and liver, for instance) are especially good candidates for FNA, as the only other way to sample them is through major surgery.
- Thyroid lumps are also excellent candidates for FNA. Such FNA procedures are typically done by a radiologist under the guidance of ultrasound or computed tomography (CT scan). The procedure requires no anesthesia, not even local.
6. Punch biopsy
- 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 stitch and heals with minimal scarring.
7. 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. This is the prominence of bone on either side of the pelvis underlying the "bikini dimples" on the lower back/upper buttocks. Hematologists perform bone marrow biopsies all the time, but most internists, pathologists and many family practitioners are also trained to perform this procedure.
- Bone marrow aspirate and biopsy can be done under sedation for young patients and if the patient is very anxious.