Biopsy
To determine whether a growth is cancerous, a biopsy (tissue sample) is extracted for further testing. Biopsies are often used in diagnosing cancer when a mass is found during a screening exam.
Biopsy procedures are guided by imaging technology, such as MRI, ultrasound or other methods, and can be performed by:
- Needle – Fine needle and core needle biopsies are used to extract cells or a small core of tissue.
- Stereotactic – Computer and imaging technology are used to guide a needle to a precise spot where a tissue sample can be collected.
- Open or surgical – A sample of the growth, or entire growth, is taken by making a small incision in the skin.
Types of Biopsies
Endoscopic biopsy: This type of biopsy is performed 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 a small incision (i.e., arthroscopy). The endoscope is used to view the organ in question for abnormal or suspicious areas, in order to obtain a small amount of tissue for study. Endoscopic procedures are named for the organ or body area to be visualized and/or treated. The physician 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 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 the skin is needed. Using a scalpel (surgical knife), a full thickness of skin is removed for further examination, and the wound is sutured (with surgical thread).
When the entire tumor is removed, it is called excisional biopsy technique. If only a portion of the tumor is removed, it is called incisional biopsy technique. 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 performed 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.