What is a biopsy?
A biopsy is a procedure done to remove tissue or cells from the body for examination under a microscope. Some biopsies can be done in a doctor's office, while others need to be done in a hospital setting. In addition, some biopsies require use of an anesthetic to numb the area, while others do not require any sedation.
Biopsies are usually done to determine whether a tumor is malignant (cancerous) or to determine the cause of an unexplained infection or inflammation.
How is a biopsy done?
A biopsy can be obtained in various ways, depending on the type of specimen needed. Flexible endoscopes (flexible, fiberoptic tubes with a viewing lens and lights) allow a surgeon to look at the inside of the body through a small incision (cut) and take out a tissue sample. Tissue samples are usually small and taken from tissue that appears changed in structure, such as a tumor.
Types of biopsies
- Endoscopic biopsy. This type of biopsy is done through a fiberoptic endoscope (a long, thin tube that has a close-focusing telescope on the end for viewing) through a natural body orifice (i.e., rectum or mouth) or a small incision (i.e., arthroscopy). The endoscope is used to look at the organ in question for abnormal or suspicious areas in order to take out a small amount of tissue for study. Endoscopic procedures are named for the organ or body area to be visualized and/or treated. The doctor can insert the endoscope into the gastrointestinal tract (alimentary tract endoscopy), bladder (cystoscopy), abdominal cavity (laparoscopy), joint cavity (arthroscopy), mid-portion of the chest (mediastinoscopy), or trachea and bronchial system (laryngoscopy and bronchoscopy).
- Bone marrow biopsy. Bone marrow aspiration and/or biopsy is a procedure that involves taking a small amount of bone marrow fluid (aspiration) and/or solid bone marrow tissue (called a core biopsy), usually from the back of the hip bones, to be examined for the number, size, and maturity of blood cells and/or abnormal cells.
- Excisional or incisional biopsy. This type of biopsy is often used when a wider or deeper portion of tissue is needed. Using a scalpel (surgical knife), a full thickness of skin or all or part of a large tumor may be removed for further examination, and the wound is sutured closed (with surgical thread).
When the entire tumor is removed, it is called excisional biopsy. If only a portion of the tumor is removed, it is called incisional biopsy. For instance, excisional biopsy is the method usually preferred when melanoma is suspected. Both types of biopsies can be performed by using local or regional anesthesia. If the tumor is inside the chest or abdomen, general anesthesia is used.
- Fine needle aspiration (FNA) biopsy. This type of biopsy involves using a thin needle and syringe to remove very small pieces from a tumor. Local anesthetic is sometimes used to numb the area, but the test rarely causes much discomfort and leaves no scar.
FNA is not used for diagnosis of a suspicious mole, but may be used to biopsy large lymph nodes near a melanoma to see if the melanoma has metastasized (spread). A computed tomography scan (CT or CAT scan)--an X-ray procedure that produces cross-sectional images of the body--may be used to guide a needle into a tumor in an internal organ, such as the lung or liver.
- Punch biopsy. Punch biopsies involve taking a deeper sample of skin with a biopsy instrument that removes a short cylinder, or "apple core," of tissue. After a local anesthetic, the instrument is rotated on the surface of the skin until it cuts through all the layers, including the dermis, epidermis, and the most superficial parts of the subcutis (fat).
- Shave biopsy. This type of biopsy involves removing the top layers of skin by shaving it off. Shave biopsies are used to diagnose some basal cell or squamous cell skin cancers, but they are not recommended for suspected melanomas of the skin. Shave biopsies are also performed with a local anesthetic.
- Skin biopsy. Skin biopsies involve removing a sample of skin for examination under the microscope to determine if melanoma is present. The biopsy is done under local anesthesia. The patient usually just feels a small needle stick and a little burning for about a minute, with a little pressure, but no pain.
Common biopsy sites
- Bone marrow
- Gastrointestinal tract (stomach and intestines)
- Lymph nodes
After a biopsy, the tissue specimen is sent to one of the following areas of anatomical pathology to be examined and analyzed:
- Surgical pathology