This expert volume in the Diagnostic Pathology series is an excellent point-of-care resource for practitioners at all levels of experience and training. Covering all aspects of gastrointestinal pathology to help pathologists differentiate between closely related digestive tract disorders, this volume incorporates the most up-to-date scientific and technical knowledge, providing a comprehensive overview of all key issues relevant to today's practice. Richly illustrated and easy to use, the fourth edition of Diagnostic Pathology: Gastrointestinal is a one-stop resource for every practicing pathologist, fellow, resident, or student as an ideal day-to-day reference or as a reliable training resource, and is useful to even the most experienced pathologist for current details on the diagnosis and characterization of neoplastic and nonneoplastic diseases of the digestive tract. Covers all areas of gastrointestinal pathology-from esoteric topics like microsporidia to common issues like serrated colorectal polyps Includes important new material on recently discovered genetic alterations in GI cancers, targeted gene therapies, and the changed approach to GI endocrine neoplasms, as well as numerous new chapters on other timely issues, such as COVID-19's effects on the GI system, drug-induced GI diseases, and more Contains significantly updated information throughout, including new content, images, and references that reflect the most current diagnoses, provide ease for daily case sign-out, and contain details related to the latest WHO Classification of Tumours: Digestive System Tumours Features more than 2,700 print and online-only images, including histology and gross pathology images, full-color medical illustrations, clinical photographs, and radiology images to help practicing and in-training pathologists reach a confident diagnosis Employs consistently templated chapters, bulleted content, key facts, annotated images, and an extensive index for quick, expert reference at the point of care Includes an eBook version that enables you to access all text, figures, and references, with the ability to search, customize your content, make notes and highlights, and have content read aloud . 10-15 new chapters plus image, text, and Reference updates across the book's ~200 chapters are in place for the 4th ed. of DP: Gastrointestinal. New chapters are added, and existing contents are updated, to address the newest WHO Classification of Digestive System Tumors. The updated Classification includes a change to how appendiceal neoplasms are classified. Additional new content covers the changed overall approach to gastrointestinal endocrine neoplasms and how to differentiate Grade 3 endocrine tumors from high grade neuroendocrine carcinomas. New 4th ed chapters also include details on targeted gene therapies and important genes now identified which involve primary cancers of the GI tract.