Definition and Overview
Percutaneous needle biopsy refers to the technique of acquiring sample cells or tissue by inserting a needle into the targeted area or organ in the body.
The major advantage of this procedure is it is minimally invasive and can thus be performed in the outpatient setting. In general, the procedure is safe and does not require stitches, eliminating the risk of general anaesthesia. It is usually performed under local anaesthesia and takes just a couple of minutes.
There are basically two kinds of percutaneous needle biopsies, depending on the kind of needle used. A fine needle aspiration biopsy uses a thin needle attached to a syringe while a core needle biopsy uses a special instrument with a thick needle, allowing more tissue to be obtained.
The use of imaging guidance in percutaneous needle biopsy has significantly improved the accuracy of the procedure when performed for masses in the abdominal and thoracic cavities. Different imaging modalities that can be used to localise the lesions include:
- Ultrasound – This is useful for superficial lesions, such as those in the neck and certain intraabdominal masses
- Computed tomography (CT) – This may also be utilised for intraabdominal masses, as well as for lesions in the thoracic cavity, particularly the lung
- Magnetic resonance imaging (MRI) - This is becoming increasingly helpful in the biopsy of adrenal and liver masses
Who Should Undergo and Expected Results
Patients with masses of unknown aetiology may undergo percutaneous needle biopsy for diagnosis. It can be performed for most tumours in various parts of the body and is vital in the diagnosis of masses in superficial locations, such as the neck, the extremities (both soft tissue and bone), and the breast, to name a few. It has also been especially beneficial in the diagnosis of tumours in deeper locations, for which mass excision requires major surgery. These tumours include those found in the lungs and abdominal organs, such as the adrenals.
Aside from diagnosis, percutaneous needle biopsy is also helpful in staging certain kinds of malignancies. This is important in selected malignancies where the presence of metastases, particularly in the lymph nodes, necessitates a different modality of therapy other than surgery.
The procedure has a sensitivity of 85 to 100% for diagnosing various tumours.
How is the Procedure Performed?
Patients undergoing percutaneous needle biopsy are typically subjected to local anaesthesia. In some instances, especially for masses in deeper locations, sedation may be used as well. For paediatric patients, general anaesthesia may be preferred.
For the procedure, the patient is positioned, depending on the site to be biopsied. The site of entry is then cleansed, prepped, and draped in a sterile manner. The mass is then localised; superficial masses are usually palpated while imaging is used to detect the location of deeper masses. For percutaneous biopsy using a fine needle, the needle is inserted from the outside until it reaches the mass, and cells are aspirated. On the other hand, if a core needle is used, a small stab incision may have to be made to accommodate the core needle. The biopsy device is then placed over the mass and fired. The needle is then removed and the tissue collected. This is repeated several times until enough tissue is obtained.
Once the specimen has been acquired, it is fixed either on a glass slide using alcohol or in a bottle containing formaldehyde. These are then sent to the laboratory for testing and pathologic review. Microscopy and staining can aid in the diagnosis, while detection of tissue markers and cultures can guide the treatment.
Pressure is applied on the biopsy site to minimise the risk of bleeding. Finally, bandage strips are placed to reapproximate the incision.
Possible Risks and Complications
The complications of percutaneous needle biopsy are mainly dependent on the location of the mass. The use of a fine needle for biopsy is associated with fewer complications, compared to the use of larger needles. Complications have been reported to occur in as much as 10%, but major complications occur in less than 1% of patients.
Bleeding is the most frequently encountered complication, and biopsy of musculoskeletal lesions can result in hematoma formation in the subcutaneous area or the muscle. These typically undergo resorption spontaneously and rarely require transfusions. For deeper locations, some sources suggest the use of gelatin sponge materials to serve as a hemostatic plug. The risk of bleeding increases when the mass is vascular or when it is located near major vessels.
Pneumothorax is a serious complication that can accompany percutaneous needle biopsy of lung lesions. This occurs in as much as 25% of patients undergoing the procedure. In approximately half of these patients, the pneumothorax is small and can be managed conservatively using high flow oxygen. However, 1 to 14% of cases may require the insertion of a chest catheter or a chest tube to drain the pneumothorax. Other complications of lung biopsy include pulmonary haemorrhage and air embolism.
Bone biopsy is associated with a slightly higher risk of developing fractures. This is especially true when weight-bearing bones are biopsied. Neurologic complications, such as the occurrence of radicular pain, have also been reported.
Biopsies of intraabdominal organs can also produce rare complications. There have been reports of bile leakage and pancreatitis following biopsy of the liver and pancreas, respectively.
Tumour seeding is also a reported complication of percutaneous needle biopsy. This is rare, occurring in less than 0.1% of patients. Some experts suggest en bloc excision of the needle site metastasis as treatment.
After the procedure, mild pain and inflammation are expected. These can usually be managed with oral anti-inflammatory and pain medications. Infection of the biopsy site may also occur, but is uncommon.
Even with the use of larger needles and image guidance, percutaneous needle biopsy may still produce negative or nondiagnostic results in approximately 10% of patients. In these situations, a repeat needle biopsy or a more invasive technique, such as open biopsy, may be necessary.
Hryhorczuk AL, Strouse PJ, Biermann JS. Accuracy of CT-guided percutaneous core needle biopsy for assessment of pediatric musculoskeletal lesions. Pediatr Radiol. 2011 Jul. 41(7):848-57.
Rimondi E, Rossi G, Bartalena T, Ciminari R, Alberghini M, Ruggieri P, et al. Percutaneous CT-guided biopsy of the musculoskeletal system: results of 2027 cases. Eur J Radiol. 2011 Jan. 77(1):34-42.