Many of us have moles, also known as nevi. These can be present at the time of birth (congenital) or can develop as we get older (acquired). They are usually benign, but some moles can change and look or act suspicious. When this occurs, it is always a good idea to have them examined by a dermatologist or other doctor trained in examining the skin and spotting abnormal moles. This exam is important because nevi can develop cancer or precancerous cells within them.
Taking a biopsy of the lesion involves removing some or all of the mole and examining it under the microscope, to see if it contains abnormal cells. (See Skin Cancer Removal for more information.) Sometimes, nevi are not suspicious, but are visible and/or unsightly; this is another reason to remove an unwanted mole.