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World J Gastroenterol. Oct 21, 2014; 20(39): 14292-14300
Published online Oct 21, 2014. doi: 10.3748/wjg.v20.i39.14292
Endoscopic ultrasound guided fine needle aspiration and useful ancillary methods
Mario Tadic, Tajana Stoos-Veic, Rajko Kusec
Mario Tadic, Department of Gastroenterology, Dubrava University Hospital Zagreb, University of Zagreb, Faculty of Pharmacy and Biochemistry, 10040 Zagreb, Croatia
Tajana Stoos-Veic, Department of Pathology and Cytology, Dubrava University Hospital Zagreb, 10040 Zagreb, Croatia
Rajko Kusec, Division of molecular diagnostics and genetics, Dubrava University Hospital Zagreb, University of Zagreb, School of Medicine, 10040 Zagreb, Croatia
Author contributions: Tadic M, Stoos-Veic T and Kusec R contributed equally to the concept and design, drafting and revising of the article and have approved the final version of the manuscript.
Correspondence to: Mario Tadic, MD, PhD, Assistant Professor, Department of Gastroenterology, Dubrava University Hospital Zagreb, University of Zagreb, Faculty of Pharmacy and Biochemistry, Av. Gojka Suska 6, 10040 Zagreb, Croatia.
Telephone: +385-1-2902550 Fax: +385-1-2902550
Received: November 28, 2013
Revised: June 25, 2014
Accepted: July 11, 2014
Published online: October 21, 2014

The role of endoscopic ultrasound (EUS) in evaluating pancreatic pathology has been well documented from the beginning of its clinical use. High spatial resolution and the close proximity to the evaluated organs within the mediastinum and abdominal cavity allow detection of small focal lesions and precise tissue acquisition from suspected lesions within the reach of this method. Fine needle aspiration (FNA) is considered of additional value to EUS and is performed to obtain tissue diagnosis. Tissue acquisition from suspected lesions for cytological or histological analysis allows, not only the differentiation between malignant and non-malignant lesions, but, in most cases, also the accurate distinction between the various types of malignant lesions. It is well documented that the best results are achieved only if an adequate sample is obtained for further analysis, if the material is processed in an appropriate way, and if adequate ancillary methods are performed. This is a multi-step process and could be quite a challenge in some cases. In this article, we discuss the technical aspects of tissue acquisition by EUS-guided-FNA (EUS-FNA), as well as the role of an on-site cytopathologist, various means of specimen processing, and the selection of the appropriate ancillary method for providing an accurate tissue diagnosis and maximizing the yield of this method. The main goal of this review is to alert endosonographers, not only to the different possibilities of tissue acquisition, namely EUS-FNA, but also to bring to their attention the importance of proper sample processing in the evaluation of various lesions in the gastrointestinal tract and other accessible organs. All aspects of tissue acquisition (needles, suction, use of stylet, complications, etc.) have been well discussed lately. Adequate tissue samples enable comprehensive diagnoses, which answer the main clinical questions, thus enabling targeted therapy.

Keywords: Endoscopic ultrasound, Endoscopic ultrasound-guided fine needle aspiration, Endoscopic ultrasound-guided tissue acquisition, Fine needle aspiration cytology, Ancillary studies, Molecular testing, Flow cytometry immunophenotyping

Core tip: All aspects of endoscopic ultrasound tissue acquisition have been well discussed in recent studies. In addition to discussions about important factors that impact tissue acquisition, in this article we have highlighted the methods of ancillary testing needed to satisfy the growing demands of precision medicine standards. Adequate tissue samples and appropriate ancillary testing enable comprehensive diagnosis, and answer the main clinical questions, thus enabling targeted therapy.