Ultrasonographically guided biopsy of small intra-abdominal masses

Ultrasonography (US) has traditionally been considered inferior to computed tomography (CT) for guidance in fine-needle aspiration biopsy (FNAB) of small intra-abdominal masses. To assess the validity of this view, the results obtained for 58 consecutive patients referred for US-guided FNAB of intra-abdominal masses of diameter 25 mm or less were retrospectively analysed. In each case two to four (usually three) aspirations were initially performed with a 22-gauge needle; sufficient tissue for diagnosis was obtained in 53 of the 58 cases (91%). The procedure had to be repeated in the other five patients to acquire diagnostic tissue. Apart from some minor abdominal pain, no complications were encountered. Proof of the cytologic diagnosis was available for 49 of the 58 patients (84%)--from histologic examination in 22 cases and from the appropriate clinical and radiologic course in 27. A sensitivity of 95% and a specificity of 90% for the technique were found for the patients for whom adequate follow-up information was available. The authors conclude that FNAB of intra-abdominal masses measuring 25 mm or less can be accurately and safely performed under US guidance.