Duodenal Duplication Cyst: A Potentially Malignant Disease

Background Duodenal duplication cysts constitute a rare congenital anomaly of the gastrointestinal tract. A recent meta-analysis of the literature between 1999 and 2009 reported a total of 47 cases of duodenal duplication cysts. 1 These abnormalities are mostly diagnosed in infancy and childhood. In rare cases, they can remain asymptomatic until adulthood, and 38 % of patients are diagnosed after age 20 years. 1 , 2 Duodenal duplication cysts are generally benign lesions; nevertheless, three cases of malignant tumours arising inside have been reported. 3 – 5 Methods In this multimedia article, we illustrated the case of an 18 year-old female patient presenting with recurrent episodes of mild pancreatitis. MRI revealed a cystic structure measuring 2.5 cm in diameter located in the duodenal wall next to the papilla of Vater. Endoscopic ultrasound showed a cystic lesion cephalad to the papilla, protruding into the duodenal lumen. Endoscopic retrograde cholangiopancreatography was not feasible due to the dislocation of the papilla, whose macroscopic aspect was normal. To further elucidate the anatomical relations, 3D reconstruction of the MRI images was performed. There was neither dilatation of the biliary tract nor a visible communication between the common bile duct and the cystic structure. The pancreatic duct also was at distance. Those findings were suggestive of a duodenal duplication. Nevertheless, the differential diagnosis 6 of a choledochocele (Todani III) could not be formally excluded. Indication for surgical resection was symptomatic disease in a context of potential malignancy. Results By right subcostal incision (video), surgical exploration revealed a soft tissue mass palpable at the second portion of the duodenum. Following duodenotomy, the mucosa was incised cephalad to the papilla of Vater, which could previously be localized by methylene blue injection by a catheter inserted into the cystic duct. The cystic structure was dissected and no communication between the cyst and the biliary tract was individualized. The final diagnosis was made by histological examination showing duodenal duplication. There was neither heterotopic gastric mucosa nor excreto-biliary epithelial layer. There were no signs of malignancy. The postoperative course was marked by hematemesis externalised by the nasogastric tube. We reintervened at postoperative day 2 to ensure hemostasis. A clot was removed from the area of duodenal mucosa without any visible active blee