Liver Biopsy

Techniques

Liver biopsy can be performed percutaneously, either blindly using percussion techniques or with ultrasound (US) guidance ( Fig. 155.1 ). US localizes an intercostal space with clear access to the liver, averting major vessels, gallbladder, and lungs. This location is marked, and the biopsy is subsequently performed at the bedside, usually in a day-surgery or ambulatory setting.

Liver biopsy can also be performed in the radiology suite under direct US or CT guidance. This technique is usually selected when biopsy is performed to study focal lesions, such as suspected hepatocellular carcinoma or adenoma. Liver biopsy can also be done using laparoscopy, although usually only when the patient is already undergoing laparoscopic surgery.

In addition to the percutaneous approach, liver biopsy can be performed using transjugular techniques, generally by interventional radiologists and for patients with a higher risk for bleeding, such as those with thrombocytopenia or coagulation abnormalities. A catheter is introduced into the right internal jugular vein and then passed into the liver through the hepatic vein. Biopsy forceps can then be used to obtain a tissue sample. The theoretic advantage of this approach is that any bleeding would occur within the vascular compartment and would be associated with a lower risk for intraabdominal bleeding.

Percutaneous liver biopsy is generally performed using local anesthesia alone, although many hepatologists have begun using a mild sedative to reduce anxiety. However, it is important that the patient be awake and alert during the performance of percutaneous liver biopsy because it is essential for patients to hold their breath, usually in the end-expiratory state. After local anesthesia with lidocaine, a trocar is used to create a tract to facilitate passage of a 16-gauge needle. A suction needle is then used to aspirate a core of liver tissue. Different types of needles are available for liver biopsy; the Klatskin needle is often used (see Fig. 155.1 ).

The biopsy specimen is usually placed in formalin or another fixative. A number of stains are used to evaluate the liver parenchyma. Hematoxylin and eosin stain is used to evaluate for inflammation and necrosis; trichrome stain is used to assess the presence and degree of fibrosis; and stains such as reticulin can be used to evaluate the architecture. In addition, special stains are useful to screen for specific liver diseases, such as periodic acid–Schiff with diastase for α ₁ -antitrypsin deficiency, Perls Prussian blue stain for iron, and a special stain for hepatitis B core antigen. Biochemical measurement of iron or copper can be performed from fresh or paraffin-embedded tissue to establish a specific diagnosis of hemochromatosis or Wilson disease, respectively.