Comparing a 25G EUS Fine Needle Aspiration (FNA) Device With a 20G EUS

Endoscopic ultrasound (EUS)-guided tissue acquisition has emerged as a valuable method to diagnose and stage malignancies. During Endoscopic Ultrasound (EUS), tissue samples can be obtained for pathological evaluation with different devices. Fine needle aspiration (FNA) provides a cytological specimen. Unfortunately, in a cytological specimen, inflammatory changes may be undistinguishable from well-differentiated dysplasia. Moreover, for neoplasms such as lymphomas and stromal tumors, tissue architecture and cell morphology are essential for accurate pathological assessment. Therefore, pathologists generally prefer a histological specimen. Fine needle biopsy (FNB) has the advantage of obtaining a histological specimen, which may lead to better diagnostic performance. However, FNB needles are stiffer and more difficult to handle, which can complicate tissue acquisition. In addition, the superiority of histology over cytology in EUS-guided tissue sampling has not been proven yet. For instance, tissue, obtained by FNA and processed with the new cell-block technique, may equal the diagnostic yield of histological tissue cores. A recent meta-analysis suggested that 25G is the optimal FNA needle size to obtain an adequate cytological specimen. In this study, we aim to compare the properties and merits of a newly designed, more flexible, 20G EUS ProCore FNB device to a conventional 25G EUS-FNA device.