Fine needle aspiration biopsy of the liver. Principal diagnostic challenges.

Fine needle aspiration biopsy (FNAB) is the diagnostic procedure of choice for evaluation of liver lesions. Although primarily applied to malignant disease, it is also used in the evaluation of benign conditions. Improvements in imaging techniques and advances in cytologic interpretations, as well as production of new biopsy needles, have all contributed to the rapid increase in radiologically guided liver FNAB.