EUS-guided fine aspiration biopsy (FNA)--indications and hazards.

Ultrasound endoscopes with mechanical sector forward scan transducers make it possible to perform FNA under EUS, and drainage by tracing the needle in the ultrasound pictures by using the same monitor unit as for radial scan ultrasound endoscopes for EUS diagnosis. It is important to diagnose the lesions from the histological findings; however, there remain some problems about false negatives, histological diagnosis from very tiny materials, and the risk of disseminating the malignant cells by the procedure.