A
medical procedure where a sample of
tissue is taken from a
tumor and then sent for tests to learn more about it - mainly, whether it is
benign or
malignant, if it is
cancerous, and if so, what kind of cancer. Typically a
local anaesthetic is used, and the doctor uses a
sterile biopsy punch (it'll have a short round tube of with a cutting edge at the end, and a hollow plastic tube as the grip (and presumably also to collect the sample, but quite frankly I wasn't too keen to watch the
doctor digging in to my leg so I didn't look too closely)) to
excise the tissue. For a small tumor/
mole, the entire thing can be removed, which is very convenient if it turns out to be malignant, but for larger abnormalities they'll just take a sample. The site is sewn up with stitches, and the sample sent to the
lab. Biopsies can also be done with a thick tipped needle, but it's the same general principle.
As far as I know, biopsies are mainly used where skin cancer of some variety is suspected, but as I'm not a physician (hell, I work in finance), I can't say for sure.