The Nonneoplastic Small Intestine Jonathan N. Glickman ▪ EMBRYOLOGY AND DEVELOPMENT There are two major steps in gastrointestinal (GI) development: the formation of the gut tube and the formation of…

Neoplastic Appendix Amy E. Noffsinger Appendiceal tumors constitute less than 0.4% of all intestinal neoplasms. Pathologically, they resemble their small and large intestinal counterparts. The most significant difference between appendiceal…

Nonneoplastic Diseases of the Appendix Amy E. Noffsinger ▪ NORMAL EMBRYONIC DEVELOPMENT The cecum appears during the 5th fetal week, arising as a diverticulum from the distal primitive intestinal loop…

Epithelial Tumors of the Small Intestine Amy E. Noffsinger ▪ GENERAL FEATURES OF SMALL INTESTINAL TUMORS Benign and malignant small intestinal tumors are uncommon. Most small bowel malignancies are metastases…

The Neoplastic Stomach Rebecca Wilcox Gastric neoplasms constitute a heterogeneous group of tumors; most are adenocarcinomas. Less common gastric cancers, such as lymphomas, neuroendocrine tumors, and mesenchymal tumors, are discussed…

The Nonneoplastic Stomach Kevin Turner Robert M. Genta ▪ THE NORMAL STOMACH Embryology The stomach develops from a fusiform foregut swelling at approximately 4 weeks’ gestation. It originates in the…

The Neoplastic Esophagus Cheryl Mather Lisa Koch Maria Westerhoff Esophageal tumors arise in any of the tissues constituting its four layers: The mucosa, submucosa, muscularis propria, and adventitia. This chapter…

Nonneoplastic Esophagus Tanya A. Rege Amy E. Noffsinger ▪ ESOPHAGEAL DEVELOPMENT The esophagus develops from the cranial part of the primitive foregut, becoming recognizable at the 2.5-mm stage of development…

General Features of the Gastrointestinal Tract and Evaluation of Specimens Derived from It Amy E. Noffsinger ▪ GENERAL COMMENTS In many ways, the gastrointestinal (GI) tract is a remarkable organ….