tailieunhanh - Chapter 087. Gastrointestinal Tract Cancer (Part 14)

Tumors of the Small Intestine Small-bowel tumors comprise | Chapter 087. Gastrointestinal Tract Cancer Part 14 Tumors of the Small Intestine Small-bowel tumors comprise 3 of gastrointestinal neoplasms. Because of their rarity a correct diagnosis is often delayed. Abdominal symptoms are usually vague and poorly defined and conventional radiographic studies of the upper and lower intestinal tract often appear normal. Small-bowel tumors should be considered in the differential diagnosis in the following situations 1 recurrent unexplained episodes of crampy abdominal pain 2 intermittent bouts of intestinal obstruction especially in the absence of IBD or prior abdominal surgery 3 intussusception in the adult and 4 evidence of chronic intestinal bleeding in the presence of negative conventional contrast radiographs. A careful small-bowel barium study is the diagnostic procedure of choice the diagnostic accuracy may be improved by infusing barium through a nasogastric tube placed into the duodenum enteroclysis . Benign Tumors The histology of benign small-bowel tumors is difficult to predict on clinical and radiologic grounds alone. The symptomatology of benign tumors is not distinctive with pain obstruction and hemorrhage being the most frequent symptoms. These tumors are usually discovered during the fifth and sixth decades of life more often in the distal rather than the proximal small intestine. The most common benign tumors are adenomas leiomyomas lipomas and angiomas. Adenomas These tumors include those of the islet cells and Brunner s glands as well as polypoid adenomas. Islet cell adenomas are occasionally located outside the pancreas the associated syndromes are discussed in Chap. 344. Brunner s gland adenomas are not truly neoplastic but represent a hypertrophy or hyperplasia of submucosal duodenal glands. These appear as small nodules in the duodenal mucosa that secrete a highly viscous alkaline mucus. Most often this is an incidental radiographic finding not associated with any specific clinical disorder. Polypoid .