A biopsy is a surgical procedure to remove a small piece of tissue or cells from the body and viewed under a microscope. Samples are taken from tissue that appears to have an altered structure, which could be a tumor.
Doctors use different procedures to obtain tissue depending on where the lesion is located on the body.
Surgical biopsy is used when a larger section of tissue is needed. When the surgery removes only a small segment of tissue, it is called incisional biopsy. Removing an entire tumor is referred to as excisional biopsy, the preferred method involving suspected melanomas.
Endoscopic biopsy is done using a long, thin tube with a special lens on the end to view the area in question, in order to remove suspected tissue. The procedure is frequently named for the organ or area being examined, such as cystoscopy (bladder), laparoscopy (abdomen), colonoscopy (bowel) and arthroscopy (joint).
Fine needle aspiration (FNA) biopsy removes tissue from the tumor with a thin needle and syringe. It is often used to examine cells in a lymph node to see if the disease has metastasized. When examining an internal organ, the surgeon may use ultrasound or a CT scan (computed tomography) to guide the needle.
Bone marrow biopsy involves removing a small amount of bone marrow tissue (a core biopsy), or bone marrow fluid (called aspiration). Most often the sample is taken from the back of the hip bones and examined for the abnormal blood cells.
Shave biopsy is used to diagnose basal cell or squamous cell skin cancers by shaving off the top layers of skin after administering a local anesthetic. It is not recommended for examining suspected melanomas.
Skin biopsy is used to diagnose melanoma by removing a sample of skin.
Punch biopsy removes a deeper sample of skin with an instrument that takes a core, or short cylinder of tissue by cutting through all layers while a local anesthesia numbs the area.
Doctors examine the harvested tissue in very thin sections and often used a variety of dyes to make cells stand out more under the microscope. Frozen sections can be examined soon after removal, a procedure often used during breast cancer surgery to determine how much tissue needs to be removed. If the specimen is in many small pieces or a liquid, a stained smear of the sample is put on slides for viewing.