Gastrointestinal Pathology. Группа авторов

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       Library of Congress Cataloging‐in‐Publication Data applied for

      HB ISBN: 9780470658369

      Cover Design: Wiley

      Cover Images: © Gregory Y. Lauwers and Michael B. Wallace

List of Contributors

      Thomas Arnason Queen Elizabeth II Health Sciences Centre and Dalhousie University Halifax Nova Scotia Canada

      Ian Brown Envoi Specialist Pathologists Brisbane Australia

      Till S. Clauditz Department of Pathology University‐Medical‐Center Hamburg Germany

      Tze Sheng Khor PathWest Laboratory Medicine Queen Elizabeth II Medical Centre Nedlands Western Australia Australia

      K. Kim Samsung Medical Center Sungkyunkwan University School of Medicine Seoul South Korea

      Bence Kővári Department of Pathology University of Szeged Szeged Hungary

      Priyanthi Kumarasinghe Department of Anatomical Pathology PathWest, QE II Medical Centre Univ. of Western Australia Perth Australia

      Gregory Y. Lauwers Moffitt Cancer Center Tampa Florida USA

      Jun Haeng Lee Samsung Medical Center Sungkyunkwan University School of Medicine Seoul South Korea

      Laurence de Leval Institute of Pathology University of Lausanne Lausanne Switzerland

      Anthony R. Mattia Newton‐Wellesley Hospital Newton, MA USA

      Christophe Rosty Envoi Specialist Pathologists Brisbane Queensland Australia

      Yutaka Saito National Cancer Center Tokyo Japan

      Mounir Trimeche Institute of Pathology University of Lausanne Lausanne Switzerland

      Michael B. Wallace Mayo Clinic Jacksonville Florida USA

Herbert C. Wolfen Mayo Clinic Jacksonville Florida USA

      Naohisa Yahaghi Keio University Cancer Center Tokyo Japan

1 General Principles of Biopsy Diagnosis of GI Disorders

       Herbert C. Wolfen1, Michael B. Wallace1, Naohisa Yahaghi2 and Yutaka Saito3

       1 Mayo Clinic, Jacksonville, Florida, USA

       2 Keio University Cancer Center, Tokyo, Japan

       3 National Cancer Center, Tokyo Japan

      Tissue sampling of the gastrointestinal tract at the time of endoscopy is the cornerstone of many gastrointestinal diagnoses. The development of a flexible endoscope and the subsequent ability to directly acquire tissue under optical guidance has been one of the most important advancements in the field of gastroenterology throughout its history. Although tissue sampling can be performed through nonendoscopic devices, the ability to directly correlate precise locations and target biopsies to specific areas of disease is critical to our ability to diagnose and further understand gastrointestinal pathology. Many of the advancements in our understanding of the basic pathology and molecular biology of gastrointestinal disease can be directly attributed to our ability to acquire tissue for histological, molecular, and genetic analyses. An excellent example is our deep understanding of the molecular pathology of colorectal cancer development from normal colonic epithelium to adenoma to colorectal cancer, a discovery made possible because of colonoscopic access to precursor lesions such as adenomatous polyps and early cancers.

      In this chapter, we will review general principles of tissue acquisition at the time of endoscopy including the following topics:

       Endoscopic equipment for obtaining tissue including endoscopic accessory channels, biopsy forceps, snare devices, needle aspiration and cytology brush.

       General principles of optimal sampling technique.

       Methods of tissue preparation in the endoscopy laboratory to optimize diagnostic accuracy.

       The role of endoscopic ultrasound (EUS)‐guided fine‐needle aspiration cytology.

Endoscopic Equipment for Tissue Sampling

      Modern endoscopic equipment can be divided in two general categories: the endoscope that allows access to the gastrointestinal tract and accessory devices that are typically passed through the working channel of the endoscope to directly acquire tissue, including biopsy forceps, snares, fine‐needle aspiration devices, and cytology brushes. Recent developments in tissue sampling include devices that are capable of wide‐field, often definitive, endoscopic resection of early neoplasia and invasive carcinoma.

A modern endoscope is a remarkably robust and versatile instrument including a light source, optical lenses with a video capture device, image processing, and display equipment, and importantly for the purposes of tissue acquisition, an accessory channel ranging from 1 to 6 mm (typically 3–4 mm), which allows passage of devices for mechanical collection of tissue (Figures 1.1 and 1.2).

There is a general trade‐off between the diameter of the instrument and the ease and comfort with which it can be passed through the natural orifices of the body such as the mouth and anus. In general the larger the outer diameter, the larger the accessory channel is to accommodate larger instruments for tissue acquisition. A fundamental limitation of most flexible endoscopes, as opposed to surgical instruments, is that all accessories pass through a single access point of the endoscope. As compared to surgical instruments with multiple access points, the endoscopic devices do not typically allow triangulation to acquire a large bulk tissue or resect entire organs. For this reason, most tissue is sampled through pinch forceps, needle aspiration, or wire loop snare devices.