Presentation and Surgical Management of Duodenal Duplication in Adults

Duodenal duplications in adults are exceedingly rare and their diagnosis remains difficult as symptoms are largely nonspecific. Clinical presentations include pancreatitis, biliary obstruction, gastrointestinal bleeding from ectopic gastric mucosa, and malignancy. A case of duodenal duplication in a 59-year-old female is presented, and her treatment course is reviewed with description of combined surgical and endoscopic approach to repair, along with a review of historic and current recommendations for management. Traditionally, gastrointestinal duplications have been treated with surgical resection; however, for duodenal duplications, the anatomic proximity to the biliopancreatic ampulla makes surgical management challenging. Recently, advances in endoscopy have improved the clinical success of cystic intraluminal duodenal duplications. Despite these advances, surgical resection is still recommended for extraluminal tubular duplications although combined techniques may be necessary for long tubular duplications. For duodenal duplications, a combined approach of partial excision combined with mucosal stripping may offer advantage.


Introduction
Duodenal duplications in adults are exceedingly rare and their diagnosis remains difficult [1][2][3]. Treatment of duplications has traditionally involved surgical resection; however, for duodenal duplications, the anatomic proximity to the biliopancreatic ampulla makes surgical management challenging [4][5][6]. In our own experience, we recently encountered a symptomatic tubular duodenal duplication in an adult. Review of available literature finds that much of our knowledge of gastrointestinal duplications comes from pediatric case series [1,[7][8][9][10][11][12]. Here, we report our experience with an adult duodenal duplication and review embryology, clinical implications, and surgical management.

Case Discussion
A 59-year-old female was referred for evaluation secondary to several months of worsening postprandial abdominal pain, early satiety, reflux, and unplanned weight loss. The patient's laboratory values were unremarkable, and past medical and surgical history were noncontributory. Radiologic evaluation included a small bowel follow-through ( Figure 1). Results of this study raised question of an abnormality involving the duodenal sweep. The duodenal C-loop was noted to be markedly dilated. At this time, two clinical diagnoses were considered. The first being that this duodenal dilation was occurring secondary to a stricture or an extrinsic compression in the fourth portion of the duodenum or at the 2 Case Reports in Surgery (a) (b) Figure 1: Representative images from the preoperative small bowel follow-through. There appeared to be marked abnormal dilation involving the duodenal C-loop. Of note, there was vigorous peristaltic activity involving this dilated loop although the peristaltic activity was disordered with a "to and from" movement of the barium and a marked delay in emptying into jejunum. The finding of peristaltic activity, although disordered, argued against the possibility of this being a duodenal diverticulum. (a) AP image. (b) Lateral image. : Preoperative endoscopic imaging. The second and third portions of the duodenum were noted to be markedly dilated with an accompanying finding of three downstream orifices. At this time, it was felt that the medial orifice (1) was the duplication and the lateral orifice (2) was the true lumen and that orifice (3) represented a distal common channel. White arrow denotes area of biliopancreatic ampulla which was proximal to the duplication.
duodenal-jejunal junction. The second possibility was that this finding represented some sort of enteric duplication. At this time, an upper endoscopy was performed ( Figure 2). Findings from the endoscopy confirmed marked dilation to the duodenal C-loop. Bile pooling was noted to accompany this dilation. Surprisingly, three downstream orifices were found just distal to the biliopancreatic ampulla; these findings were again suggestive of a duodenal duplication. At that time, a surgical referral was obtained and the decision was made to proceed with operative exploration. The patient underwent an open abdominal exploration. Initial inspection found the second and third portions of the duodenum to be markedly dilated as had been observed on prior imaging (Figures 3(a)-3(b)) with a normal appearing distal jejunum. The retroperitoneal attachments of the duodenum were then taken down. The gallbladder was removed using a standard top-down approach; the cystic duct was identified and a biliary Fogarty balloon catheter was inserted into the duodenum so as to clearly delineate the location of the ampulla. Further medial mobilization of the duodenum was then performed, and at this time, it became apparent that the duplication extended superiorly, anterior to the body of the pancreas. Repeat intraoperative endoscopy was performed. Again, three orifices were confirmed to be just distal to the ampulla. A planned enterotomy was then created on the anterior surface of the duplication just distal to the ampulla; at this time it became apparent that one of these lumens was the true lumen, which connected to the distal jejunum. The other two orifices were lumens involving the duplication. Following clear delineation of anatomy, the tubular duodenal duplication was fully mobilized and resected ( Figure 4(a)). A point of transection was chosen just distal to the ampulla with the distal resection line occurring at the jejunum. Accordingly, a hand-sewn end-to-side duodenojejunostomy was then fashioned (Figure 4(b)). In combining preoperative imaging and intraoperative findings, the final defined anatomy was consistent with that of a tubular duodenal duplication of the third and fourth portions of the duodenum.

Clinical Findings
Most enteric duplications are identified by the age of two years, with less than thirty percent being diagnosed in adults [3]. The large majority of duodenal duplications are cystic and intraluminal [31]. They most commonly arise from the mesenteric border of the second and third portions of the native duodenum, and accordingly, there is a tendency for them to be closely associated with both the pancreatic and biliary ducts. By comparison, extraluminal tubular duodenal duplications are rare [31,32]. Cystic duodenal duplications are typically fluid-filled and however may, on occasion, contain gallstones, bile, or pancreatic fluid [32,33]. Both computer tomography (CT) and ultrasound are useful imaging modalities [26,28]. Ultrasound of cystic duplications should reveal an anechoic fluid-filled doublewalled cyst composed of an inner hyperechoic rim of mucosasubmucosa and an outer hypoechoic layer of smooth muscle consistent with the muscularis propria; in contrast, although frequently difficult to capture, a classically identifying feature of tubular duplications is peristalsis [34]. For CT imaging, oral contrast used with CT imaging can be helpful as it will not fill a cystic duplication because of lack of communication with the gastrointestinal tract but rather may delineate it by demonstrating compression effect on adjacent structures whereas a tubular duplication would be expected to fill [29].

Treatment Options
Review of earlier literature highlights the complexity and surgical difficulty in treating enteric duplications. It is important to note that management of cystic intraluminal and tubular extraluminal duodenal duplications typically varies. Cystic intraluminal duplications are increasingly more amendable to drainage alone whereas extraluminal tubular duplications typically necessitate formal surgical resection.
Historically, prior attempts to create a drainage limb while leaving an intraluminal cystic duplication intact via a surgical cystjejunostomy resulted in incomplete long-term success primarily because of retained heterotrophic gastric tissue and long-term risk of peptic ulceration, bleeding, or malignancy [4,5,39]. Recent advances in endoscopy have expanded on this idea with successful drainage accomplished via endoscopic marsupialization [39]. Review of the literature finds that there are eight children who underwent endoscopic management and remained asymptomatic after mean followup of over seven years, thus suggesting that this may be a safe and effective technique [40,41]. Concerns regarding malignancy or bleeding from peptic ulceration still exist in this setting, as endoscopic therapy does not always result in complete ablation of the cyst mucosa; this risk, however, appears to be low.
In contrast, current surgical understanding and practice still largely recommends resection for tubular extraluminal duplications. Complete resection for short segmental duplications may be possible whereas combined techniques may be necessary for longer segmental duplications. Duodenal duplications, in particular, pose a unique challenge as their anatomic proximity to the ampulla makes surgical management more complex. Of note, duodenal duplications typically arise just distal to the biliopancreatic ampulla in comparison to choledochoceles which are typically found proximal [41]. A combined approach of partial excision combined with mucosal stripping offers one such solution [5,6,22]. From the pediatric literature, mucosal stripping is a practical surgical option as it removes the secretory mucosa and also reduces the future risk of peptic ulceration and malignancy. Of note, during this process, the shared blood supply between the duplication and the native bowel must be protected and preserved so as to avoid the need for resection [3].

Conclusion
Despite a large historic experience, duodenal duplications in adults continue to be rare and their diagnosis remains difficult. Clinical symptoms in adults are nonspecific and potential risks, if untreated, including risk of peptic ulceration and malignant transformation. The treatment of duplications has traditionally involved surgical resection; however, for duodenal duplications, the anatomic proximity to the ampulla makes surgical management more challenging. For intraluminal cystic duodenal duplications, advances in endoscopy have changed current practice; however management of extraluminal tubular duplications remains challenging. In this setting, a combined approach of partial excision combined with mucosal stripping may offer advantage.