Expertise and training of endosonographer and interaction with the cytopathologist have also an important role [7-14-15]. Up to now three different sizes of needle are available for collecting cytological material: 25 - 22 and 19 gauge with an aspiration volume syringe of 10ml. Most of the studies on EUS-FNA have been conducted using 22G needles. Data on thinner (25G) or larger (19G) needles are limited. A number of recent studies, including two RCTs, compared results obtained with needles of various diameters. All these studies were performed in the setting of pancreatic masses [18-20]. Although thinner needles provide less cellular material than do larger needles, the specimens from the former are less contaminated by blood, and thus easier to interpret. In addition, thinner needles may be easier to use because of greater flexibility, particularly for locations requiring important scope bending [18, 19]. An RCT in 131 patients found no significant differences between 22G and 25G needles in terms of diagnostic yield for malignancy [17]. Finally another RCT compared EUS-FNA without ROSE using 19G or 22G needles in 117 patients [18] showed a similar diagnostic accuracy for both needles.