A biopsy is a medical test involving the removal of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease.
The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically. When an entire lump or suspicious area is removed, the procedure is called an ''excisional biopsy''.
When only a sample of tissue is removed with preservation of the histological architecture of the tissue’s cells, the procedure is called an ''incisional biopsy'' or ''core biopsy''.
When a sample of tissue or fluid is removed with a needle in such a way that cells are removed without preserving the histological architecture of the tissue cells, the procedure is called a needle aspiration biopsy.
Common Biopsy Sites
Bone marrow
Since blood cells are formed in the bone marrow, a bone
marrow biopsy is employed in the diagnosis of abnormalities of blood
cells when the diagnosis cannot be made from the peripheral blood
alone. In malignancies of blood cells (leukemia and lymphoma) a bone
marrow biopsy is used in staging the disease. The procedure involves
taking a core of trabecular bone using a trephine, and then aspirating
material.
Gastrointestinal tract
Flexible endoscopy enables access to the upper and lower
gastrointestinal tract, such that biopsy of the esophagus, stomach and
duodenum via the mouth and the rectum, colon and terminal ileum are
commonplace. A variety of biopsy instruments may be introduced through
the endoscope and the visualized site biopsied. Until recently, the
majority of the small intestine could not be visualized for biopsy. The
double-ballon “push-pull” technique allows visualization and biopsy of
the entire gastrointestinal tract..
Needle core biopsies or aspirates of the pancreas may be made through the duodenum or stomach.
Lung
Biopsies of the lung can be performed in a variety of ways depending on the location.
Liver
In hepatitis, most biopsies are not used for diagnosis,
which can be made by other means. Rather, it is used to determine
response to therapy which can be assessed by reduction of inflammation
and progression of disease by the degree of fibrosis or, ultimately,
cirrhosis.
In Wilson's disease, the biopsy is used to determine the quantitative copper level.
Further Reading
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