VALUE OF ANCILLARY STUDIES IN FINE-NEEDLE ASPIRATION BIOPSY

With growing interest in the application of fine-needle aspiration bio psy (FNAB) in primary diagnosis of benign and malignant lesions, there has been a significant increase in the use of ancillary studies in th e aspirated material. To assess the value of such studies, we reviewed 254 morphologically difficult aspiration biopsy cases obtained from d ifferent sites that underwent ancillary studies which included microbi ology (MC), special stains (SS), immunocytochemistry (ICC), electron m icroscopy (EM) and flow cytometry (FC). Correlation with available his tologic material and/or pertinent clinical information was used as a ' 'gold'' standard. In some cases, more than one ancillary study was per formed on a single aspirate. According to the impact of the ancillary studies on the final diagnosis, these studies were divided into three categories: confirmatory/diagnostic (22%), helpful (41%), and non-help ful (37%). Overall, more studies had positive contributory effect to t he diagnosis (63%) than those with non-helpful results (37%). Among th ese adjunct testings, ICC were the most commonly used tests (135/296, 46%), while the EM studies had more positive impact in establishing th e diagnosis. These findings emphasize the usefulness of ancillary test ings in FNAB and justify the more selective use of these studies in th e aspirated material. (C) 1995 Wiley-Liss, Inc.