A biopsy is a procedure in which a sample of tissue is removed from the body for examination. A diagnosis is made when cells are examined through a microscope. There are several ways biopsy samples can be obtained. Needle biopsy is used when a lesion or tumor can be felt or identified on imaging studies. During the procedure, a thin hollow needle is inserted into the lesion and guided by x-ray or ultrasound equipment. A small sample of the tissue is removed for analysis. When suction is applied to the needle to obtain a sample, the procedure is called an aspiration biopsy. An incisional biopsy is performed when abnormal tissue is not directly accessible by less invasive methods, or when a larger specimen is desired. During this surgical procedure, local anesthetic is administered and a section or portion of a tumor is removed. Sutures are required to close the skin following an incisional biopsy. These biopsies are usually performed as an outpatient procedure. During an excisional biopsy, local anesthetic is administered and the surgeon cuts into or through the skin to remove the entire tumor, as well as some of the surrounding normal tissue. In some cases, removal of all abnormal tissue at a site completes the need for diagnosis and treatment. Following tissue removal, the incision is closed with sutures. Frozen section is used when a biopsy specimen needs to be obtained and analyzed immediately during surgery. Frozen section analysis may be necessary to determine: - Whether the tumor or abnormal growth is benign or cancerous. - If more tissue is needed for diagnosis. - If the cancer has spread or metastasized. - If all of the cancer has been removed, and if the surgical margins are free of cancer. During a frozen section, the biopsy specimen is placed in a cryostat, a special freezer that can rapidly freeze a specimen. The specimen is then cut and placed on a microscopic slide, where it can then be quickly stained and analyzed.