Biopsy

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.

Etymology
Biopsy is of Greek origin, coming from the words bio, meaning life, and opsia, meaning to see.

History
One of the earliest diagnostic biopsies was developed by the Arab physician Abulcasim (1013-1107 AD). A needle was used to puncture a goiter, and the material issuing was characterized.

Cancer
When cancer is suspected, a variety of biopsy techniques can be applied. An excisional biopsy is an attempt to remove an entire lesion. When the specimen is evaluated, in addition to diagnosis, the amount of uninvolved tissue around the lesion, the surgical margin of the specimen is examined to see if the disease has spread beyond the area biopsied. "Clear margins" or "negative margins" means that no disease was found at the edges of the biopsy specimen. "Positive margins" means that disease was found, and a wider excision may be needed, depending on the diagnosis. When intact removal is not indicated for a variety of reasons, a wedge of tissue may be taken in an incisional biopsy. In some cases, a sample can be collected by devices that "bite" a sample. A variety of sizes of needle can collect tissue in the lumen (‘’core biopsy’’). Smaller diameter needles collect cells and cell clusters, fine needle aspiration biopsy. Pathologic examination of a biopsy can determine whether a lesion is benign or malignant, and can help differentiate between different types of cancer. In contrast to a biopsy that merely samples a lesion, a larger excisional specimen called a resection may come to a pathologist, typically from a surgeon attempting to eradicate a known lesion from a patient. For example, a pathologist would examine a mastectomy specimen, even if a previous nonexcisional breast biopsy had already established the diagnosis of breast cancer. Examination of the full mastectomy specimen would confirm the exact nature of the cancer (subclassification of tumor and histologic "grading") and reveal the extent of its spread (pathologic "staging").

Precancerous conditions
For easily detected and accessed sites, any suspicious lesions may be assessed. Originally, this was skin or superficial masses. X-ray, then later CT, MRI, and ultrasound along with endoscopy extended the range.

Inflammatory conditions
A biopsy of the temporal arteries is often performed for suspected vasculitis. In inflammatory bowel disease (Crohn's disease and ulcerative colitis), frequent biopsies are taken to assess the activity of disease and to assess changes that precede malignancy.

Biopsy specimens are often taken from part of a lesion when the cause of a disease is uncertain or its extent or exact character is in doubt. Vasculitis, for instance, is usually diagnosed on biopsy.


 * Kidney disease: Biopsy and fluorescence microscopy are key in the diagnosis of alterations of renal function. The immunofluorescence plays vital role in the diagnosis of Crescentic glomerulonephritis.


 * Infectious disease: Lymph node enlargement may be due to a variety of infectious or autoimmune diseases.


 * Metabolic disease: Some conditions affect the whole body, but certain sites are selectively biopsied because they are easily accessed. Amyloidosis is a condition where degraded proteins accumulate in body tissues. In order to make the diagnosis, the gingival.


 * Transplantation: Biopsies of transplanted organs are performed in order to determine that they are not being rejected or that the disease that necessitated transplant has not recurred.


 * Fertility: A testicular biopsy is used for evaluating the fertility of men and find out the cause of a possible infertility, e.g. when sperm quality is low, but hormone levels still are within normal ranges.

Analysis of biopsied material
After the biopsy is performed, the sample of tissue that was removed from the patient is sent to the pathology laboratory. A pathologist is a physician who specializes in diagnosing diseases (such as cancer) by examining tissue under a microscope. When the laboratory (see Histology) receives the biopsy sample, the tissue is processed and an extremely thin slice of tissue is removed from the sample and attached to a glass slide. Any remaining tissue is saved for use in later studies, if required. The slide with the tissue attached is treated with dyes that stain the tissue, which allows the individual cells in the tissue to be seen more clearly. The slide is then given to the pathologist, who examines the tissue under a microscope, looking for any abnormal findings. The pathologist then prepares a report that lists any abnormal or important findings from the biopsy. This report is sent to the physician who originally performed the biopsy on the patient.