Ultrasound-guided percutaneous fine needle aspiration biopsy of abdominal and retroperitoneal masses. Accuracy of cytology in the diagnosis of malignancy, cytologic tumor typing and use of antibodies to intermediate filaments in selected cases.

The reliability of ultrasound-guided fine needle aspiration biopsy (FNAB) in the detection of intraperitoneal and retroperitoneal malignancies was evaluated in 308 consecutive cases seen between 1979 and 1983. The prevalence of malignant neoplasms was 68.5%. The overall accuracy of FNAB diagnosis was 88.9%, with a sensitivity of 84.4% and a specificity of 98%. The predictive value of positive and negative results were 98.9% and 74.6%, respectively. Additionally, the cytologic results were statistically evaluated with respect to the different sites of the biopsied lesions (including pancreas, liver, kidneys and miscellaneous sites). The overall accuracy was highest for malignant lesions in the liver (96.4%) and in miscellaneous sites (89.5%). Reasons for false-negative results included incorrect areas sampled, limited material due to fibrosis or necrosis and cytologic misinterpretations. The accuracy of cytologic tumor typing with respect to histogenetic origin was 96.8%. Cytologic subclassification was performed with lower accuracy (82.5%), and exact determination of the site of the primary tumor from cytologic criteria alone was possible for 35.7% of carcinomas. In selected cases, routine cytologic examination was supplemented by intermediate filament typing using well-characterized antibodies against cytokeratin, vimentin, desmin and neurofilaments. Examples are shown in which use of this method clearly increased the accuracy of the diagnosis. Only two serious complications (bleeding) of fine-needle aspiration biopsy were encountered in this series.