A breast biopsy is a procedure performed while in the office while you’re awake to obtain a sample of tissue to evaluate a breast lump or an abnormality that was seen on a mammogram, ultrasound or MRI. Copious amounts of local anesthetic (numbing medicine) are used to the numb the skin and deeper tissue in the breast to minimize discomfort. A needle is then placed in the abnormality in the breast to obtain tissue. A small marker is usually left to mark the location where the biopsy was taken. The tissue is then sent to the pathologist to be evaluated under the microscope and obtain a diagnosis. Breast biopsies are usually performed using breast imaging guidance, usually an ultrasound or a mammogram machine. Results from the biopsy usually are available in one or two business days.