What is the difference between fine needle aspiration and core biopsy?
Percutaneous needle biopsy includes two basic techniques for obtaining tissue samples: FNA and core biopsy. NA refers to sampling using thin hollow needles (20 gauge [G] and smaller) that extract loose cells for cytologic evaluation. Core biopsy refers to the use of hollow needles (20 G and larger) with a cutting mechanism that extracts a thin cylinder of tissue, usually 1 to 2 cm long, for histologic evaluation. The size of the needle and the use of aspiration or core biopsy depend on the target organ and the type of lesion that requires sampling. Most cancers can be diagnosed by cytologic analysis, but certain lesions require assessment of histopathologic architecture of tissue for diagnosis. In most cases, needle aspirations are adequate for differentiating benign from malignant disease and can serve to stage patients with cancer. However, the majority of patients do not undergo surgical resection, and specimens obtained for therapeutic planning purposes should allow for extended diagnoses, including the determination of biomarker profiles. In the current era of personalized medicine and targeted chemotherapies, molecular studies of biopsy samples is increasingly necessary, and evaluation for these markers often requires core biopsy specimens. Both types of biopsies can be performed during a single procedure, if needed, thus obtaining both cytologic and histologic specimens. Which type of biopsy to perform is determined by the type of tumor suspected, the size and location of the lesion, and what information is necessary for treatment planning.