DIAGNOSING MESOTHELIOMA: WHAT IS A BIOPSY? Malignant mesothelioma is a rare type of cancer that forms in the mesothelium, the lining that surrounds the body’s internal organs. Because it is so rare, and because its symptoms can indicate other conditions, it can be very difficult to diagnose. A conclusive diagnosis usually requires a biopsy, or the removal of a sample of cells or tissue for examination under the microscope. Before the Biopsy A biopsy is not the first step in diagnosing mesothelioma. First, the physician will assess the patient’s symptoms and examine the patient’s health history to look for clues to what is causing illness. Pleural mesothelioma, which occurs in the lining of the lungs, often causes symptoms such as pain or swelling in the chest or abdomen; trouble breathing; and weight loss. A history of asbestos exposure is often associated with mesothelioma, providing the physician with another clue for diagnosis. Other diagnostic tests, such as a chest X‐ray and CBC (complete blood count,) provide additional pieces of information that help the doctor make an accurate diagnosis. If tests and health history are consistent with mesothelioma, a biopsy allows the doctor to make a conclusive diagnosis. The biopsy is an effective diagnostic tool, but it’s not the first used because removing a sample of cells or tissue is more invasive than a simple X‐ray or blood draw. Types of Biopsies Some biopsies require no anesthesia or only local anesthesia. In these, the physician removes tumor samples through a thin needle or a flexible, lighted tube called an endoscope. In other cases, a biopsy requires surgery and general anesthesia. Different procedures are used to collect cell or tissue samples, depending on the suspected location of cancer. These include:  Fine‐needle aspiration biopsy: The physician uses a thin needle to remove a sample of possibly‐diseased cells.  Thoracotomy: The physician makes an incision between two ribs to to collect a tissue sample and to check inside the chest for signs of disease.  Thoracoscopy: The physician makes an incision between two ribs and inserts a thin, lighted tube into the chest. The tube contains a tool to collect cells for examination under a microscope.  Peritoneoscopy and laparotomy: These procedures are similar to the thoracoscopy, but the incision is made in the abdominal wall. A thin, lighted tube is used to examine inside the abdomen and to collect cells for examination under a microscope. After the sample has been removed it will be sent to a pathologist, a physician who specializes in cancer and its diagnosis. This doctor will examine the cells under a microscope to check for abnormalities. In some cases, the first biopsy will remove fluid from around the lungs or from the abdomen. The pathologist will examine the cells Cheryl M. Reifsnyder, Ph.D. Web site content, lay audience found in this fluid for signs of cancer; however, many physicians consider this test insufficient for mesothelioma diagnosis. Understanding Your Care Before any medical procedure, it is the patient’s right to understand the potential benefits, risks, and side effects. If your physician recommends a biopsy, be sure to bring up any questions or concerns. You may want to know the reason for the procedure or the information it will provide. Find out what sort of anesthesia you will need, and how you should expect to feel afterward. The more you learn about the procedure, the better you’ll know what to expect—and the more comfortable you’ll feel with your care. Cheryl M. Reifsnyder, Ph.D. Web site content, lay audience