The removal of cells or tissues by a surgeon for
examination. A pathologist may then study the tissue under a microscope or
perform other tests on the cells or tissue. There are many different types of
biopsy procedures. The most common types include: (1) incisional biopsy, in
which only a sample of tissue is removed; (2) excisional biopsy, in which an
entire lump or suspicious area is removed; and (3) needle biopsy, in which a
sample of tissue or fluid is removed with a needle. When a wide needle is used,
the procedure is called a core biopsy. When a thin needle is used, the
procedure is called a fine-needle aspiration biopsy1.