What is a Biopsy Test?
Introduction
A biopsy is a test that is generally performed by a surgeon to extract tissue samples or sample cells for examination purposes to determine if a disease is present or the extent of it. The tissue is usually examined by a certified pathologist and can be analyzed chemically. When an individual has certain issues such as having a lump, a biopsy helps to determine if there is cancer. Although imaging tests like X-ray, computed tomography (CT), or magnetic resonance imaging (MRI) can be useful to help detect the diseases, it cannot differentiate if the growth is malignant or benign, and the histological type of cancer if present. For most cancers, a biopsy is the best way for a definitive diagnosis as the cells are collected for examination. Biopsies can be categorized according to the type of biopsy done.
Types of Biopsies
Some of the different biopsies include:
Bone Marrow Biopsy
When there is a suspicion of cancer or abnormality in the blood, a bone marrow biopsy may be recommended. The bone marrow can be found inside larger bones. This is where blood cell production occurs. A bone marrow biopsy can help determine the cause of the anomaly in the blood. Some of the conditions that a bone marrow biopsy can help diagnose include blood cancers such as multiple myeloma, leukemia, and lymphoma. It can also detect cancers that have spread to the bone marrow. During this procedure, the doctor draws a bone marrow sample from the back of the hipbone. To minimize the discomfort, a local anesthetic will be administered.
Needle Biopsy
As the name suggests, a needle biopsy occurs when a needle is used to extract cells from an area suspected to have abnormal growth. This is most commonly performed on lumps and enlarged lymph nodes so cells from these growths can be examined. If the area is not visible or cannot be felt, this procedure can be combined with imaging to collect the cells from a deeper growth. It can be further divided into:
Core needle biopsy – This procedure uses a large cutting tip needle to “core” out a column of tissue for examination purposes.
Fine needle aspiration – This uses a long thin needle where a syringe is used to draw out cells and fluids for analysis.
Vacuum-assisted biopsy – A suction device can be used to increase the number of cells and fluids extracted so it reduces the number of times the needle is inserted to collect an adequate amount of sample.
Image-guided biopsy – This procedure combines an imaging procedure with a needle biopsy to allow access to areas that cannot be seen through the skin.
Endoscopic Biopsy
In this procedure. A thin and flexible tube with a light is inserted to see the internal structures while specialized tools pass through the tube to collect tissue samples. This can be inserted into the rectum, mouth, urinary tract, or skin incision.
Skin Biopsy
A skin biopsy removes cells from the skin surface and can be used to diagnose skin conditions. Some of the types of skin biopsy are shave biopsy, excisional biopsy, incisional biopsy, and punch biopsy.
Surgical Biopsy
During a surgical biopsy, an incision can be made on the skin to remove the tissue that needs to be examined. This procedure removes an abnormal area of cells. Local or general anesthetics may be required during the procedure.
Uses
As previously mentioned, some of the uses of biopsy include the diagnosis of cancer. It can also be used to examine if the cancer has spread by analyzing the edges of the specimen. A positive margin would mean that a wider excision is needed. The pathologic examination of the tissue will determine if the lesion is benign or malignant and to differentiate between different cancer types. In inflammatory conditions such as vasculitis and inflammatory bowel disease, biopsies help in the assessment of disease activity and changes that may precede malignancy. It can be useful in kidney disease, metabolic disease, infectious disease, transplantation, and fertility assessment.
Analysis and Results
Once a tissue sample is obtained, it is sent to the laboratory to be analyzed. Depending on the preference, it can be frozen or chemically treated before sectioned into thin slices. These slices are then placed on a glass slide, stained, and examined under a microscope. The results from the pathologist will help the clinician determine the course of action. The biopsy also helps determine the aggressiveness of the cancer. Low-grade cancers are less aggressive at grade 1 while grade 4 cancers are high grade and highly aggressive. This information helps to guide treatment as options may differ. In some cases, the samples are examined immediately, and results are available within minutes.
References
Biopsy. Wikipedia. Accessed 9/16/2019. https://en.wikipedia.org/wiki/Biopsy
Biopsy: types of procedures used to diagnose cancer. Mayo Clinic. Accessed 9/16/2019. https://www.mayoclinic.org/diseases-conditions/cancer/in-depth/biopsy/art-20043922