Fine Needle Aspirate; a Vital Technique in the Characterization of Masses and Lesions - Abstract
Fine needle aspiration is a cost effective, non-invasive, less painful, rapid reporting bedside diagnostic procedure for obtaining small amount of sample from palpable and non-palpable masses or lesions in the body using a needle. The objective of FNA is to provide information on the nature of the sampled tissue in order to focus appropriate diagnostic and therapeutic decisions, all at minimal risk to the patient. Its sensitivity in distinguishing benign from malignant tumours varies from 58% to 96% with specificity
usually between 90 to 100%. In the characterization of lesions and masses using FNA, the concept of ‘‘triple test’’, that is the combination of physical examination, imaging findings and cytologic examination, is recommended. The triple test is positive if any of the three components is positive, and negative if all the components are negative. The triple test has sensitivity (true positive rate) of 99.6%, and a specificity of 93%. More so, a combination of FNA and Cell-block technique revealed sensitivity of 94% and specificity of 98%. However, a minimum number of epithelial cells (5–10 cells/group) for FNA made diagnosis have been advocated, and samples containing fewer than the specified minimum be considered non-diagnostic. Despite the reported specificity and sensitivity of FNA, proper training of personnel and adherence to recommendations are quite important in producing reliable result.