Comprehensive Primer on EUS-Guided Tissue Acquisition

Contents

Foreword: New Methods to Obtain Better Tissue Samples with EUS-guided FNA ix

Charles J. Lightdale

Preface: EUS-Guided Tissue Acquisition xi

Shyam Varadarajulu and Robert H. Hawes

The Changing Paradigm in EUS-Guided Tissue Acquisition 1

Shyam Varadarajulu and Robert H. Hawes

The diagnostic performance of endoscopic ultrasound-guided fine-needleaspiration is strongly dependent on the availability of an onsite cytopathol-ogist. The diagnosis of some rare tumors may require ancillary testing forwhich a histologic core biopsy is required. There is increasing interest inevaluating core tissue for molecular markers that may serve as prognosticpredictors and targets for focused chemotherapy in patients with cancer. Ifcore tissue can be procured efficiently and reliably at endoscopic ultra-sound, this will eliminate the need for an onsite cytopathologist, accuratelydiagnose tumors that are occasionally missed by fine-needle aspirationcytology, and enable the assessment for molecular markers.

Beyond Cytology: Why and When Does the Oncologist Require Core Tissue? 9

Sebastian G. de la Fuente and J. Pablo Arnoletti

There are 2main reasonswhy oncologistsmay require additional tissue anda histologic section in addition to cytopathology from fine-needle aspiration(FNA) specimens: improved diagnostic accuracy and molecular character-ization of tumors. Rather than mutually exclusive diagnostic procedures,endoscopic ultrasound (EUS)-FNA and EUS- core needle biopsy must beviewed as supplementary techniques and both approaches should beincorporated as essential tools in the current endoscopic armamentarium.

Definitions in Tissue Acquisition: Core Biopsy, Cell Block, and Beyond 19

Nirag Jhala and Darshana Jhala

This article identifies key fundamentals of tissue acquisition, sample prep-aration, and staining. It defines the understanding of different aspects ofsample preparations, such as types of smear-preparation techniques,touch preparations, types of fixative, and newer technologies such asliquid-based preparations.

How Can an Endosonographer Assess for Diagnostic Sufficiency and Options forHandling the Endoscopic Ultrasound-Guided Fine-Needle Aspiration Specimenand Ancillary Studies 29

Shantel Hébert-Magee

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) hasbecome well established as a minimally invasive technique in diagnosingand staging various gastrointestinal, pancreaticobiliary, and retroperitoneal

Contentsvi

malignancies. The diagnostic accuracy of this procedure is significantlyenhanced by the presence of on-site cytopathology. However, in manyEUS centers, cytopathology is not readily available for on-site evaluation.This article is intended to assist the independent endosonographer in theassessment of diagnostic sufficiency and in specimen handling.

Endoscopic Ultrasound-Guided Fine-Needle Aspiration Needles: Which One and inWhat Situation? 57

Zeid Karadsheh and Mohammad Al-Haddad

Videos of the fanning technique and the uncinate processaccompany this article

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is increas-ingly used as a diagnostic and therapeutic tool for pancreatic and other gas-trointestinal disorders. Several factors affect the outcome of EUS-FNA, oneof which is needle size. The decision to use a specific needle depends onfactors including location, consistency, and type of the lesion; presence ofonsite cytopathologist; and need for additional tissue procurement for his-tology. This review provides a balanced perspective on the use of differentneedle sizes available, highlighting the differences among them and poten-tial niche applications of each to maximize diagnostic yield of EUS-FNA.

Techniques for EUS-guided FNA Cytology 71

Sarto C. Paquin and Anand V. Sahai

This article addresses the technique of endoscopic ultrasound-guidedfine-needle aspiration of solid lesions to obtain cytologic specimens. Thetechnique can be broken down into a sequence of steps. The ultimategoal is to maximize the likelihood of obtaining adequate tissue for diagnos-tic purposes. This requires a technique that ensures that the needle can bemoved inside the lesion, under ultrasound guidance, as widely as possible,as easily as possible, and safely. The other variables such as suction,needle type, and stylet use are of secondary importance.

Techniques for Endoscopic Ultrasound-Guided Fine-Needle Biopsy 83

Nikola Panic and Alberto Larghi

Although endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA)is the method of choice to obtain samples to reach definitive diagnosis oflesions of the gastrointestinal tract and of adjacent organs, it cannotfully characterize certain neoplasms. The lack of cytology expertise hashindered the dissemination of EUS, limiting its widespread use. Obtaininga tissue specimen through EUS fine-needle biopsy (EUS-FNB) may over-come the limitations of EUS-FNA. EUS-FNB is expected to move the prac-tice of EUS from cytology to histology, expanding the use of EUS andfacilitating targeted therapies and monitoring of treatment response ina more biologically driven manner.

Tips to Overcome Technical Challenges in EUS-guided Tissue Acquisition 109

Peter Vilmann, Andrada Seicean, and Adrian S�aftoiu

The diagnostic yield of EUS-FNA depends on several factors, such as theexperience of the endosonographer, the characteristics of the lesion, the

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clinical status of the patient, the size and type of needles, the methods ofspecimen preparation, as well as cytopathologist expertise. The endoso-nographic technique can be improved when several tips and tricks usefulto overcome challenges of FNA are known. Technical challenges of FNAare related to the characteristics of the lesion and its surroundings, sono-graphic imaging, and limitations related to the needle. Several tips andtricks necessary to overcome them are presented in this review.

Pitfalls in EUS FNA 125

Larissa L. Fujii and Michael J. Levy

Although endoscopic ultrasound (EUS) fine-needle aspiration (FNA) isa safe and accurate procedure, the diagnostic yield varies. Factorscontributing to the diagnostic accuracy of EUS FNA include endosonogra-pher and cytopathologist experience, EUS image recognition, accurateFNA targeting of the lesion, proper specimen collection and handling,use of ancillary techniques, and accurate cytologic interpretation. Errorsin performance or judgment made before, during, or after the proceduremay affect the results of the EUS FNA. The authors discuss the potentialpitfalls of EUS FNA and methods to avoid their occurrence to optimizethe diagnostic yield, efficiency, and safety of the procedure.

Future Directions in EUS-guided Tissue Acquisition 143

Pierre H. Deprez

Endoscopic ultrasound fine-needle aspiration is considered the techniqueof choice for acquisition of tissue in and around the digestive tract. Theemergence of selective, targeted therapies, directed toward a particularmolecular characteristic of an individual patient’s tumor is driving theneed for biomarker identification and testing in several cancer types.The technique needs improvement to provide more material, in fewerpasses, with more flexible, sharp, and clearly echovisible needles, andwith a similar safety. Another trend is the avoidance of tissue acquisition,or a more targeted puncture with the help of ancillary techniques, such asoptical biopsies with needle-based confocal laser endomicroscopy, con-trast-enhanced ultrasonography, and elastography.

Index 151