In general, a biopsy is tissue removal for the purpose of microscopically examining the tissue by a doctor who specializes in the field of pathology. An excision biopsy is a procedure done to remove a mass of tissue that is possibly malignant or cancerous. It is essential for diagnosing and treating small or non-metastatic cancers such as melanomas and localized cancers such as breast cancer. This procedure can also be used to detect deeper or metastatic cancers, upon which surgical or medical procedures considered as definitive treatments can be performed.
Sometimes called surgical biopsy, an excision biopsy involves either tissue or organ removal. It can be done to remove suspicious lumps of the skin, breast, thyroid, and other parts of the body. There may be times when the mass is not visible and is located deep within the body. For instance, the para-aortic lymph nodes near the aorta and the heart may be enlarged due to metastatic lung cancer. In this case, an excision biopsy is performed to remove the lymph nodes and examine them.
When a breast lump is detected and cancer is suspected, an excision biopsy may be the preferred method for removing the lump. Wire-guided biopsy of the breast is a special type of surgical biopsy wherein a radiologist assists the surgeon in the removal of the lump. A mammography machine is used to visualize the lump and to insert a needle connected to a wire. The surgeon follows the wire and cuts out the breast mass, which is then sent to a pathologist for definitive diagnosis. Wire-guided biopsy is best used for breast lumps that are seen on mammography but are not palpable or visible.
In an excision biopsy, the removed specimen is histologically or microscopically examined. The pathologist evaluates the surgical margin of the removed tissue. If the pathologist reports that there are clear or negative margins, it means no cancerous cells have been found at the edges of the specimen. When the pathology report states positive margins it means cancerous cells have been found at the margins, and a wider excision is needed for treatment of the disease.
An important advantage of doing an excision or surgical biopsy is obtaining a large specimen, thereby decreasing the probability of diagnostic error. This procedure requires stitches, leaves a scar, and may cause significant bleeding or infection. The decision to do excision biopsy instead of other biopsy techniques usually depends on the type of malignancy suspected, how large the mass is, and how accurate the diagnosis will be.