Duodenal adenocarcinoma is the most common primary malignancy of the duodenum.
Adenocarcinoma is the most common primary malignant neoplasm of the duodenum. It represents 0.3% of all gastrointestinal malignancies and accounts for 50-70% of small bowel adenocarcinomas occurring either in the duodenum or proximal jejunum.
The peak incidence is in the 7 decade. More than 50% of them have metastases at the time of diagnosis .
Most of the clinical features are non-specific and include upper abdominal pain and weight loss as the most common presenting symptoms. In the late phases of the disease, a variety of symptoms and signs have been reported, such as symptoms of proximal intestinal obstruction and jaundice, hematemesis, melena, and fecal occult blood. A variety of other findings, such as low back pain and alteration in bowel habit, have also been described.
Grossly they have a napkin ring appearance or appear as a polypoid fungating mass. Patients with familial adenomatous polyposis and Gardner syndrome are considered to have a higher likelihood of developing duodenal cancer. Patients who have duodenal polyps without a predisposing family history are also at an increased risk .
- distal portion (3 and 4 parts): 45%
- second part: 40%
- first part: 15%
According to some publications, upper GI series is the most accurate diagnostic modality for small-bowel carcinomas . Upper GI shows features of mucosal pattern distortion, obliteration and narrowing. Delayed images may show barium holdup at the site of the lesion .
The lesions appear as irregularly hypoechoic masses. Ultrasonography can diagnose and assess the vascularity of larger lesions but the smaller tumors (<2 cm) may not be detected .
CT is the modality of choice for the staging of the disease by identifying the primary tumor and assessing local, nodal, and distant spread .
Demonstration of lesions facilitated by negative contrast agents (water):
- intrinsic mass with a short segment of bowel wall thickening
- invasion of retroperitoneal fat planes, pancreatic and biliary duct, vascular encasement, lymph nodal and distant metastases is common in later stages
Treatment and prognosis
Duodenal adenocarcinoma is associated with a delayed diagnosis and poor prognostic and survival outcomes due to non-specific clinical presentation.
Metastasis, poor tumor differentiation, increased depth of spread and pre-existing Crohn's disease are associated with poor prognosis.
Recurrence of the tumor is also a common entity. The most common sites of recurrence are the liver, lungs and peritoneum .
The only possibility of improving prognosis is the early diagnosis of the primary tumor, which affords a higher chance of tumor resectability .
Pancreaticoduodenectomy is required for tumors of the first and second portion of the duodenum. In tumors of the distal duodenum, segmental resection may be adequate .
General imaging differential considerations include:
- pancreatic head/uncinate process tumors
- lower common bile duct tumors
- periampullary tumors
- regional colonic carcinoma with duodenal invasion