The Value of Gastrointestinal Biopsy

Introduction Prior to the development of the first fibre-optic endoscopes in the 1960s, gastroenterology, in common with other traditional medical specialties, relied on biochemical and radiological techniques to investigate the gastrointestinal (GI) tract. Histological confirmation of a disease process usually required the presence of a surgeon, was invasive, and carried inherent risks. Because of a rapid improvement in technology, we are now able to sample the entire GI tract from the mouth and anus through to the ileal–jejunal junction. In addition, endoscopy can now sample beyond the mucosa into the submucosa and extra-luminal structures, because of the development of endoscopic ultrasound. Therefore, in many ways the history of GI pathology has mirrored the development of GI endoscopy. With the exponential growth in the use of endoscopy since the early 1970s, there is a continually increasing need to interpret the GI pathophysiology and immunology through the lens of a 1 to 2 mm sample of mucosa embedded in formalin. Like any investigative process, dialogue between the endoscopist framing the question and the pathologist attempting to answer it is crucial. The keys to success are clear communication, meticulous specimen labelling, sufficient clinical information, and forums for feedback and discussion such as multidisciplinary meetings, research, or simply coffee and a chat. All of these combine to embed the histopathology report within the clinical environment. This chapter sets out to explain the value of histology to a gastroenterologist or surgeon, particularly in benign disease, and sets out the latest guidelines for endoscopic sampling in the upper, mid, and lower GI tract. Finally, it aims to explain to a histopathological audience the decision-making process that endoscopists follow when performing an endoscopic procedure and, crucially, what the endoscopist needs in return in a pathology report.