Lung Biopsy Health Article

Definition

Lung biopsy is a procedure by which a small sample of lung tissue is obtained for examination. Usually, it is examined under the microscope and also may be sent to the microbiological laboratory for culture. Microscopic examination is performed by pathologists.

Purpose

A lung biopsy is usually ordered to determine the cause of abnormalities that appear on chest x rays, such as nodules or infiltrates. Lung biopsies are performed to confirm a diagnosis of cancer, especially if malignant cells are detected in the patient's sputum or bronchial washing. In addition to evaluating lung tumors and their associated symptoms, lung biopsies may be used in the diagnosis of lung infections, especially tuberculosis and Pneumocystis pneumonia, drug reactions, and chronic diseases of the lung such as sarcoidosis.

A lung biopsy can be used for treatment as well as diagnosis. Bronchoscopy, a type of lung biopsy performed with a long slender instrument called a bronchoscope, can be used to clear a patient's air passages of secretions and to remove blockages from the airways. Today, flexible fiberoptic bronchoscopes, which are easier to use than rigid scopes, are used to perform most biopsies.

Precautions

As with any other biopsy, lung biopsies should not be performed on patients who have a tendency to bleed or abnormal blood clotting because of low platelet counts or prolonged prothrombin time (PT) or partial thromboplastin time (PTT). Platelets are small blood cells that play a role in the blood clotting process. PT and PTT measure how well blood clots. If they are prolonged, it might be unsafe to perform a biopsy because of the risk of bleeding. If the platelet count is lower than 50,000/cubic mm, the patient may be given a platelet transfusion as a temporary relief measure, and a biopsy can then be performed.

Overview

The mediastinum separates the right and the left lungs from each other. The heart, the trachea, the lymph nodes, and the esophagus lie in the mediastinum. Lung biopsies may involve mediastinoscopy, as well as the lungs themselves.

Types of lung biopsies

Lung biopsies can be performed using a variety of techniques. A bronchoscopy is ordered if a lesion identified on the x ray seems to be located in the periphery of the chest. If the suspicious area lies close to the chest wall, a needle biopsy can be done. If both these methods fail to diagnose the problem, an open lung biopsy may be performed. When there is a question about whether the lung cancer has spread to the lymph nodes in the mediastinum, a mediastinoscopy is performed.

NEEDLE BIOPSY. About an hour before the needle biopsy procedure, a sedative is administered to the patient. The patient is mildly sedated but fully awake. An X ray technician takes a computerized axial tomography (CT) scan to identify the location of the suspicious areas. Markers are placed on the overlying skin to mark the biopsy site. The skin is thoroughly cleansed with an antiseptic solution, and a local anesthetic is injected to numb the area.

The physician then makes a small incision, about half an inch (1.25 cm) in length. The patient is asked to take a deep breath and hold it while the physician inserts the biopsy needle through the incision into the lung. When enough tissue has been obtained, the needle is withdrawn. Pressure is applied at the biopsy site and a sterile bandage is placed over the cut. The entire procedure takes between 30 and 45 minutes.

The patient may feel a brief sharp pain or some pressure as the biopsy needle is inserted. Most do not experience severe pain.

OPEN BIOPSY. Open biopsies are performed in a hospital operating room under general anesthesia. As with needle biopsies, patients are sedated before the procedure. An intravenous line is placed to give medications or fluids as necessary. A hollow tube, called an endotracheal tube, is passed through the mouth, into the airway leading to the lungs. It is used to convey the general anesthetic.

Once the patient is anesthetized, the surgeon makes an incision over the lung area, a procedure called a thoracotomy. Some lung tissue is removed and the incision is closed with sutures. The entire procedure usually takes about an hour. A chest tube is sometimes placed with one end inside the lung and the other end protruding through the closed incision. Chest tube placement is done to prevent the lungs from collapsing by removing the air from the lungs. The tube is removed a few days after the biopsy.

A chest x ray is done following an open biopsy, to check for a pneumothorax (lung collapse). The patient may experience some grogginess for a few hours after the procedure. Patients also may experience tiredness and muscle aches for a day or two, because of the general anesthesia. The throat may be sore because of the placement of the endotracheal tube. The patient may also have some pain or discomfort at the incision site, which can be relieved by pain medication.

VIDEO-ASSISTED THORASCOPIC SURGERY. A new technique, video-assisted thorascopic surgery (VATS), also can be used to biopsy lung and mediastinal lesions. VATS may be performed on selected patients in place of open lung biopsy. To perform a VATS procedure, the surgeon makes several small incisions in the patient's chest wall. A thorascope, a thin, hollow, lighted tube with a tiny video camera mounted on it, is inserted through one of the small incisions. The other incisions allow the surgeon to insert surgical instruments to retrieve tissue for biopsy.

MEDIASTINOSCOPY. The preparation for a mediastinoscopy is similar to that for an open biopsy. The patient is sedated and prepared for general anesthesia. The neck and the chest are cleansed with an antiseptic solution.

After the patient is anesthetized, an incision about two or three inches long is made at the base of the neck. A thin, hollow, lighted tube, called a mediastinoscope, is inserted through the incision into the space between the right and the left lungs. The surgeon removes any lymph nodes or tissues that look abnormal. The mediastinoscope is then removed, and the incision is sutured and bandaged. A mediastinoscopy takes about an hour.