inverted duodenal diverticulum is an infrequent congenital abnormality that usually is not symptomatic but can become , generally in adult life .
this anatomical anomaly has been also related to episodes of upper intestinal bleeding or even acute pancreatitis ( 1,2 ) .
we present a case of an inverted duodenal diverticulum in a patient that presented with an upper intestinal obstruction .
a 33-year - old woman with a previous history of fertilization treatments , consulted because of a 2 months vague epigastric and right hypocondric discomfort that was especially more frequent after eating .
the patient referred a sensation of fullness / pressure , nausea and abundant alimentary vomiting 2 - 3 hours after eating and that relieved the pain .
she was also afraid of eating and had lost 9 kg of weight during this period .
upper gastrointestinal series showed the presence of an intraluminal duodenal diverticulum of about 8 cm in length and a partially occluded duodenal lumen ( figure 1 ) .
intraluminal duodenal diverticulum , pear - shaped sac , occluding duodenal lumen ( arrows ) .
an upper gastrointestinal endoscopy showed a inverted intraduodenal diverticulum like a  giant pseudo - polip  that insufflated and deinsufflated spontaneously ( figure 2 ) .
upper intestinal endoscopy showing the inverted intraduodenal diverticulum the cholangio - mri and the abdominal ct scan also showed the diverticulum ( figure 3 ) , as well as signs of upper intestional malrotation , absence of the pancreatic tail , polysplenia and an hepatic artery that emerged from the superior mesenteric artery .
a cholecistectomy , a transcystic cannulation of vater s papilla and a longitudinal duodenotomy on the second portion were performed .
an intraluminal formation of 10 cm of length , anchored to three quarters of the duodenal circumference , right next to the papilla and covered by normal mucosa on both sides , was revealed .
after circumferencial excision of the inverted intraduodenal diverticulum , an approximation of both mucosal edges was done with reabsorbible stitches , controlling vater 's papilla .
the patient was discharged on day 8 after surgery with no complications , except for an autolimited episode of upper intestinal bleeding .
only a low percentage of gastrointestinal diverticula are  inverted  or  intraluminal diverticula  , that is , they have the sac protruding into the duodenal lumen , and less than 150 cases have been previously described in the literature ( 3 ) .
this lesion is usually found in the 2 portion of the duodenum , very often near vater s papilla , as in our patient , covering a variable percentage of the surface of the duodenum .
its origin has been related to a defect in the development of the duodenum which takes place between the 5 and the 12 week of gestation ( 1 ) . during this period the complete obliteration of the lumen , the vacuole formation , and the subsequently coalescence of the vacuoles until the complete and definitive permeabilization of the duodenal lumen takes place .
patients with duodenal diverticula are going to present an impaired and incomplete vacuolization ( 4 ) .
duodenal vacuolization occurs at the same time as the biliary and pancreatic ducts develop and explains the relationship between both congenital defects ( 5,6 ) .
there is a 40% incidence of coexistant anatomical abnormalities : choledochocele , annular pancreas , double diverticula , intestinal malrotation , imperforate anus , hirschsprung`s disease , congenital heart diseases , omphalocele , hypoplastic kidneys , bladder exstrophy , situs inversus , ladd s bands , portal vein anomalies , polysplenia and down syndrome ( 6,7 ) .
the distended diverticulum acts as a large foreign body in the lumen which contributes to produce postprandial fullness and , in some patients , signs of upper intestinal obstruction .
when the duodenum is empty , the diverticulum has a tendency to collapse ; this explains the asymptomatic periods .
regarding diagnosis , barium contrast radiology shows images that could be considered patognomonic , with a  bag  of retained barium in the 2 duodenal portion , occlusive or subocclusive , surrounded by a double radiolucid image with perisacular mucosa duodenal folds .
this image has been described as a  windsock blown  into the duodenum ( 8) . the endoscopy can have false negatives because of the device being introduced into the lumen of the diverticulum .
specific findings are  a blind sac lined by normal duodenal mucosa that gives the appearance of a polyp when inverted  ( 5 ) . in the presented case ,
ct scans and cholangio - mri allow physicians to complete the study and to evaluate concomitant congenital abnormalities .
( 9 ) when the patient develops symptoms , conservative management usually has a poor outcome .
nevertheless , surgery is considered as the best treatment , consisting in an anterior duodenotomy and the excision of the diverticulum ( 1,6 ) .
procedures like wide kocher 's manouver , or the indentification of vater 's papilla , biliar duct and pancreatic duct are essentials ( 3 ) .
the diverticulum must be extirpated from the mucosa belonging to the  real  duodenum in a circumferential manoeuvre .
if it is necessary to reconstruct the papilla or the opening of the pancreatic duct , a silicone stent can be used .
( 1 ) we conclude that inverted duodenal diverticula should be considered in the differential diagnosis of upper intestinal obstruction of unknown cause .
physicians should keep in mind the particular considerations related to vater 's papilla and congenital malformations associated to this condition .
 inverted intraduodenal diverticulum is a rare congenital abnormality usually arising near the ampulla of vater . 
 we describe a case of an inverted duodenal diverticulum in a patient that presented with an upper recurrent intestinal obstruction that required surgery . 
 recognition of the entity and its anatomic relationships to the ampulla of vater is essential to the prevention of iatrogenic complications . 
 the inverted intraduodenal diverticulum must be considered in the management of upper intestinal obstruction of unclear origin . 
INTRODUCTION
CASE REPORT
DISCUSSION