Duodenal tumours 

Benign duodenal tumours

Duodenal villous adenomas occur principally in the periampullary region. Although generally uncommon, they are often found in patients with familial adenomatous polyposis. Indeed, malignant transformation in such adenomas is the commonest cause of death in patients with polyposis who have had the colon removed. The appearances are similar to those adenomas arising in the colon and, as they have malignant potential, should be locally excised with histologically clear margins. 

Endocrine tumours

A number of endocrine neoplasms occurs in the duodenum. It is a common site for primary gastrinoma (Zollinger—Ellison syndrome). Other endocrine tumours include carcinoid tumours that, by comparison with ileal carcinoids, are uncommon. 

Zollinger—Ellison syndrome

This syndrome is mentioned here because the gastrin-producing endocrine tumour is often found in the duodenal loop, although it also occurs in the pancreas, especially the head. It is a cause of persistent peptic ulceration. Before the development of potent gastric antisecretory agents the condition was recognised by the sometimes fulminant peptic ulceration which did not respond to gastric surgery short of total gastrectomy. It was also recognisable from gastric secretory studies in which the patient had a very high basal acid output but no marked response to pentagastrin, as the parietal cell mass was already near maximally stimulated by pathological levels of gastrin. The advent of proton pump inhibitors such as omeprazole has rendered this extreme endocrine condition fully controllable, but also less easily recognised.

Gastrinomas may be either sporadic or associated with the autosomal dominantly inherited multiple endocrine neoplasia (MEN) type I (in which a parathyroid adenoma is almost invariable). The tumours are most commonly found in the ‘gastrinoma triangle’ (Passaro) defined by the junction of the cystic duct and common bile duct superiorly, the junction of the second and third parts of the duodenum inferiorly, and the junction of the neck and body of the pancreas medially (essentially the superior mesenteric artery). Many are found in the duodenal loop, presumably arising in the G cells found in Brunner’s glands. It is extremely important that the duodenal wall is very carefully inspected endoscopically and also at operation. Very often all that can be detected is a small nodule which projects into the medial wall of the duodenum.

Even malignant sporadic gastrinomas may have a very indolent course. The palliative resection of liver metastases may be beneficial and liver transplantation is practised in some centres, as for other gut endocrine tumours, with reasonable long-term results. However, the minority of tumours found to the left of the superior mesenteric artery (outside the ‘triangle’) seems to have a worse prognosis, more having liver metastases at presentation. In MEN type I the tumours may be multiple and the condition is incurable. Even in this situation, as with sporadic gastrinoma, surgical treatment should be employed to remove any obvious tumours and associated lymphatic rnetastases as the palliation achieved may be extremely gratifying.

Duodenal adenocarcinoma

Although uncommon, this is the commonest site for adenocarcinoma arising in the small bowel. Most tumours originate in the periampullary region and commonly arise in pre­existing villous adenomas. Patients present with anaemia due to ulceration of the tumour or obstruction as the polypoid neoplasm begins to obstruct the duodenum. Direct involve­ment in the ampulla leads to obstructive jaundice. Histologically, the lesion is a typical adenocarcinoma and the rnetastases are commonly to regional lymph nodes and the liver. At presentation about 70 per cent of the patients have resectable disease and for those who survive operation the 5-year survival rate is in the region of 20 per cent, this approximately equating to cure. Poor prognostic features in the resected specimen include regional lymph node metastases, transmural involvement and perineural invasion. Curative surgical treatment will normally involve a pancreatrco­duodenectomy (Whipples procedure). Patients with familial polyposis, which is due to a mutation in the APC gene on chromosome 5, are predisposed to periampullary cancer which is one of the most common causes of death in patients who have had their colon removed.

Other duodenal malignancies are rare.