Duodenal obstruction due to annular pancreas associated with carcinoma of the duodenum

Annular pancreas, the second most common anomaly of the pancreas, is the development of a ring of pancreatic tissue that surrounds and often embraces the duodenum. It was first described by Tiedelmann in 1818 and named “annular pancreas” by Ecker in 1862 [1]. It is usually present in childhood, with symptoms due to duodenal obstruction. In 50% of cases, clinical manifestations become visible after childhood, with abdominal pain, chronic duodenal obstruction, peptic ulceration, obstructive jaundice, pancreatitis, and pancreatic head mass [2, 3]. Therefore, duodeno-jejunostomy is usually applied to relieve strictures caused by such an annulus. Bypass surgery is the treatment of choice [4].
Primary duodenal carcinoma is rare and represents 0.3% of all gastrointestinal malignancies and 25–35% of malignant tumours of the small intestine [5, 6]. Resectability and the presence of distant metastatic disease are the strongest determinants of outcome for patients with duodenal adenocarcinoma. In cases of cancers of the first and second part of the duodenum, the most common procedure is pancreaticoduodenectomy. Despite advancements in techniques of diagnosis and resection and decreased perioperative mortality and morbidity, 5-year survival varies from 37% [7] to 57% [8].
Malignancy in the setting of annular pancreas is an unusual event, and hence only a few cases associated with pancreatic carcinoma, ampullary carcinoma, and cholangiocarcinoma have been reported [9–13]. Only 1 case of annular pancreas associated with duodenal carcinoma has been reported, but without description of the follow-up [14]. We report a case of duodenal carcinoma in a patient with an annular pancreas treated with radical surgery with complete follow-up data.
A 53-year-old lady suffered from nausea, post-prandial fullness, and vomiting, and weight loss. She was diagnosed (endoscopy Figure 1, CT scan of the abdomen Figure 2) to have duodenal obstruction with gastric bezoar. The upper intestinal contrast study findings of annular filling defect in the duodenum, prestenotic dilatation, and reverse peristalsis in the proximal segment were suggestive of annular pancreas. A pathology report of the endoscopic biopsy material taken from the stenotic part of the duodenum revealed suspicion of malignancy, i.e. atypic cells. The patient was scheduled for a laparotomy with intraoperative pathological investigation of the suspected lesion, and if malignancy is proven a...


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