biopsy (bīäp´sē), examination of cells or tissues removed from a living organism. Excised material may be studied in order to diagnose disease or to confirm findings of normality. Preparatory techniques depend on the nature of the tissue and the kind of study intended. Incisions may be made and total or partial lesions removed in the form of wedges or cylindrical pieces, or scrapings of the surface membranes of internal organs may be collected. Needlelike instruments may be used to pierce the tissues and remove soft inner material. Once the tissue specimen has been obtained it is fixed, i.e., membrane proteins and enzymes are stabilized and chemical and histologic analyses are carried out by pathologists. Tumors are routinely biopsied in order to determine whether they are malignant. Fine needle aspiration is a technique more readily used for certain tumors or lesions because it is less expensive and damaging than traditional surgical biopsy.