Duodenum Malignant Tumors

Although the duodenum comprises less than 10% of the total length of small bowel, 21% of benign tumors and 23% of malignant tumors of the small bowel originate in the duodenum. Accordingly, the duodenum has a higher frequency of neoplasm per unit of length than the jejunum and ileum. Approximately 50–55% of duodenal tumors are malignant. They have nearly equal sex distribution and their age distribution is similar to that seen in the entire small intestine, with the majority of patients being older than 50 years (Zouhairi et al. 2008; Heinrich and Clavien 2010; Maglinte et al. 2008; Levine et al. 2008a, b). Since the duodenum is the first part of the small intestine it is at risk for similar tumors. The distribution of adenocarcinomas, carcinoid, and lymphoma presents a clear trend along the length of the small bowel. Most adenocarcinomas occur in the duodenum and their relative frequency decreases in an aboral direction. Carcinoid tumors show an opposite trend with increasing frequency in the aboral direction. Similarly lymphoma occurs more frequently in the ileum than in the jejunum and duodenum (Lee et al. 2008a; Hu et al. 2006). The majority of duodenal tumors are symptomatic and the most common clinical manifestations are intermittent obstruction with nausea, vomiting, and cramping abdominal pain. Bleeding is also common and produces anemia, melena, or hematemesis. Less frequently, patients present with jaundice indicating that the lesion arises from the ampulla of Vater.