A biopsy is a medical procedure in which cells or tissue are removed from a living person for laboratory examination. A specialist in pathology, called a pathologist, examines the specimen, usually with a microscope, and may perform additional tests to identify disease. Biopsies are important in the diagnosis of cancer, but they also investigate many noncancerous conditions. The term refers to obtaining the specimen; the laboratory examination is a related but distinct process. (medlineplus.gov)
Clinical purposes
A biopsy can establish whether an abnormal area is cancerous, identify the type of cancer, and provide information relevant to treatment. Imaging and physical examination can reveal suspicious abnormalities, but microscopic examination is often necessary to determine their nature. A biopsy does not, by itself, imply that cancer is present. (cancer.gov)
Noncancerous indications depend on the organ being sampled. Skin biopsies can investigate infections, inflammation, and disorders such as psoriasis. A bone marrow biopsy can investigate abnormal blood-cell production and help diagnose blood disorders, including leukemia and lymphoma. Different sampling methods provide different kinds and quantities of diagnostic material. (medlineplus.gov)
Principal sampling methods
Fine-needle aspiration uses a thin needle to withdraw fluid, individual cells, or small cell clusters. Its examination is primarily cytological: it emphasizes the appearance of cells rather than their arrangement within intact tissue. Although commonly described as a biopsy, aspiration differs from methods that retrieve a substantial tissue fragment. (cancer.org)
Core needle biopsy uses a larger hollow needle to remove small cylinders of tissue. These cores preserve more tissue architecture than an aspirate. Vacuum-assisted systems draw tissue into a sampling chamber and can collect multiple specimens through a single insertion. (cancer.org)
Incisional biopsy removes part of an abnormal area, whereas excisional biopsy removes the entire area or mass being investigated. These are forms of surgical sampling; the choice depends on factors such as size, location, and the diagnostic question. Removing a lesion for diagnosis does not necessarily constitute complete cancer treatment. (cancer.org)
Skin biopsy includes shave sampling of superficial layers and punch sampling with a circular cutting instrument that obtains a deeper tissue cylinder. An endoscopic biopsy obtains tissue using instruments passed through a thin viewing tube, allowing sampling inside organs such as the stomach or colon. (medlineplus.gov)
Localization and procedure
Accessible abnormalities may be sampled directly. Deeper lesions can require image guidance using ultrasonography, computed tomography, or magnetic resonance imaging. Imaging helps locate the target and guide the sampling instrument. Local anesthesia is common in needle procedures; sedation or general anesthesia may be used depending on the procedure and patient. Some biopsies are outpatient procedures, while others require an operating room. (radiologyinfo.org)
Laboratory examination
In histological examination, tissue structure and the relationships between cells are assessed. Routine preparation commonly involves fixation in formalin, processing, embedding in paraffin wax, cutting thin sections, and staining them for microscopy. Cytopathology instead examines individual cells and small groups obtained through aspiration or other collection methods. These approaches provide related but different diagnostic information. (cancer.gov)
A frozen section provides a rapid examination, often during an operation. Tissue is frozen, cut, stained, and examined without the longer preparation required for permanent sections. This can answer an immediate surgical question, although permanent sections generally preserve greater structural detail. (cancer.gov)
Additional analyses can characterize abnormalities beyond their microscopic appearance. Immunohistochemistry uses antibodies to detect particular proteins in tissue. Molecular testing can examine DNA and identify changes in genes or other biomarkers. In cancer, these results may refine classification or identify features relevant to particular treatments; not every detected change has established clinical significance. (cancer.org)
Reporting and limitations
A pathology report records the specimen’s origin, how it was obtained, its visible characteristics, microscopic findings, and the diagnosis. Cancer reports may include tumor grade, evidence of invasion, and findings from additional tests. Margin status describes whether cancer reaches the edge of removed tissue, when the specimen permits that assessment. A small biopsy does not necessarily provide all the information needed to determine cancer stage. (cancer.gov)
Sampling imposes important limitations. A needle biopsy may miss an abnormality or retrieve too little material for a definite diagnosis. Additional testing can also be limited by insufficient tumor tissue. Cancer cells within the same tumor may have different biomarkers, and those features can change over time: a specimen represents the material collected at a particular site and time. (radiologyinfo.org)
Risks and liquid biopsy
Risks depend on the sampling site and technique. They include bleeding, infection, discomfort, and accidental injury to nearby structures. Needle sampling is generally less invasive than surgical biopsy, but neither method is risk-free. (radiologyinfo.org)
A liquid biopsy analyzes blood or another body fluid for tumor-derived material, including circulating cells or DNA fragments. Unlike conventional tissue biopsy, it does not retrieve intact tissue architecture. It can provide molecular information relevant to cancer care, but detection is affected by how much tumor-derived material reaches the fluid and by the test’s sensitivity. Low concentrations, particularly from small tumors, can limit detection. (cancer.gov)