A biopsy is a specimen taken from a part of the body. It may be taken by syringe aspiration with a fine (thin) needle or a thicker one (core biopsy); it may be clipped, scraped, or cut during procedures like endoscopy, or during surgery. Skin biopsies may be shaved off, or cut out by either a small instrument or a scalpel. Sometimes it’s necessary to do deep surgery to obtain the biopsy specimen.
Biopsy specimens can be cultured for bacteria or other germs. They’re always examined under a microscope, sometimes using special stains. This is the main way to diagnose a number of diseases, especially more uncommon ones, and the only way to diagnose cancer. “Imaging,” like x-rays, mammograms, CT scans, etc., may suggest cancer, but the only way to know for sure, and to tell what kind, is by examining a piece of the tumor itself.