Endoscopic ultrasound-guided tissue acquisition beyond the pancreas

Endoscopic ultrasound (EUS) offers the ability to obtain tissue material via a fine needle under direct visualization for cytological or pathological examination. Prior studies have looked at EUS tissue acquisition; however, most reports have been centered around lesions of the pancreas. This paper aims to review the literature on EUS tissue acquisition in other organs (beyond the pancreas) such as the liver, biliary tree, lymph nodes, and upper and lower gastrointestinal tracts. Furthermore, techniques for obtaining tissue samples under EUS guidance continue to evolve. Specifically, some of the techniques that endoscopists employ are suction techniques (i.e., dry heparin, dry suction technique, wet suction technique), the slow pull technique, and the fanning technique. Apart from acquisition techniques, the type and size of the needle utilized play a major role in the quality of samples. This review describes the indications for tissue acquisition for each organ, and also describes and compares the various tissue acquisition techniques, as well as the different needles used according to their shape and size.