Mesenchymal Tumors General Comments Gastrointestinal (GI) spindle cell tumors caused diagnostic confusion for decades. Previously, most were diagnosed as either smooth muscle or neural tumors. However, following decades of ultrastructural…
Lymphoproliferative Disorders of the Gastrointestinal Tract In this discussion of gastrointestinal lymphoproliferative disorders the emphasis will be on neoplastic diseases. The lymphoid hyperplasias will be considered only in the context…
Gastrointestinal Neuroendocrine Lesions General Organization of the Gastrointestinal System The gastrointestinal neuroendocrine system (GNES) is the largest and most complex endocrine organ in the body (1). The gut contains numerous…
Neoplastic Lesions of the Anus General Comments Anal tumors are predominantly squamous in nature, and while they are rare, they have shown an increase in recent years due to the…
The Nonneoplastic Anus Embryology The anal canal develops from the distal hindgut. Early in development, the hindgut, allantois, and urogenital tracts end in a common cloaca. Later, the urogenital septum…
Adenocarcinoma Incidence and Death Rates The highest incidence rates for colon cancer occur in North America, Australia, and New Zealand, as discussed previously in this chapter. The risk for colorectal…
Evaluation of Resection Specimens General Comments The unopened bowel should be carefully examined upon receipt from the operating room, then opened and pinned to a corkboard for fixation in 10%…
Distinguishing Colonic Neoplasms from Neoplasms from Other Sites There are two types of problems one encounters with respect to metastatic carcinomas of the colon. The first is determining if a…
Secondary Tumors The large bowel may be the site of metastasis or extension from a number of tumors. It may also be involved by direct invasion or extension, intraperitoneal seeding,…
