annular pancreas ( ap ) is a rare congenital anomaly that causes congenital duodenal obstruction in the newborn period . it is usually suspected during routine prenatal ultrasonography by the double bubble sign in the fetal abdomen , and the diagnosis and treatment are straightforward soon after birth . however , the degree of duodenal obstruction and the subsequent obstructive symptoms might be variable , and unrecognized ap has been detected in adolescents or even in adults in some cases.1,2 we report herein a case of an ap in an 11-year - old girl , which was successfully treated by a conventional operation . the case review was conducted according to all guidelines outlined in the declaration of helsinki . written informed consent for publication of this case report was obtained from the girl s parents . an 11-year - old girl presented with a 10-year history of early satiety and recurrent vomiting after a meal . her birth history was unremarkable , and she had been treated symptomatically with the clinical diagnosis of chronic gastroenteritis for her recurrent vomiting . on physical examination , her height was 142 cm and body weight was 42 kg , and no other abnormal findings could be identified . on laboratory examination , the white blood cell count was 6,200 cells/l ( normal : 4,00010,000 cells/l ) , hemoglobin was 12.9 g / dl ( normal : 13.316.5 g / dl ) , and albumin was 4.5 g / dl ( normal : 3.24.8 g / dl ) . abdominal ultrasound scan was normal , but the upper gastrointestinal ( ugi ) study revealed a distended duodenal bulb accompanied by diffusely narrowed second portion of duodenum , suggesting extrinsic compression of the duodenum ( figure 1a ) . abdominal computed tomography ( act ) demonstrated pancreatic parenchyma encircling the second portion of duodenum , and ap was diagnosed ( figure 1b ) . laparoscopic duodenoduodenostomy was attempted , but the dense adhesion between the ap and the transverse colon precluded laparoscopic approach , and conventional diamond - shaped duodenoduodenostomy was performed through an upper abdominal transverse incision . as there was no gross dilatation of the proximal segment , a tapering duodenoplasty was not required . the postoperative course was uneventful , and the symptoms disappeared 2 weeks after the operation . postoperative ugi series ( ugis ) taken 3 months later showed good passage through the bypass without evidence of extrinsic compression ( figure 2 ) . the case review was conducted according to all guidelines outlined in the declaration of helsinki . written informed consent for publication of this case report was obtained from the girl s parents . an 11-year - old girl presented with a 10-year history of early satiety and recurrent vomiting after a meal . her birth history was unremarkable , and she had been treated symptomatically with the clinical diagnosis of chronic gastroenteritis for her recurrent vomiting . on physical examination , her height was 142 cm and body weight was 42 kg , and no other abnormal findings could be identified . on laboratory examination , the white blood cell count was 6,200 cells/l ( normal : 4,00010,000 cells/l ) , hemoglobin was 12.9 g / dl ( normal : 13.316.5 g / dl ) , and albumin was 4.5 g / dl ( normal : 3.24.8 g / dl ) . abdominal ultrasound scan was normal , but the upper gastrointestinal ( ugi ) study revealed a distended duodenal bulb accompanied by diffusely narrowed second portion of duodenum , suggesting extrinsic compression of the duodenum ( figure 1a ) . abdominal computed tomography ( act ) demonstrated pancreatic parenchyma encircling the second portion of duodenum , and ap was diagnosed ( figure 1b ) . laparoscopic duodenoduodenostomy was attempted , but the dense adhesion between the ap and the transverse colon precluded laparoscopic approach , and conventional diamond - shaped duodenoduodenostomy was performed through an upper abdominal transverse incision . as there was no gross dilatation of the proximal segment , a tapering duodenoplasty was not required . the postoperative course was uneventful , and the symptoms disappeared 2 weeks after the operation . postoperative ugi series ( ugis ) taken 3 months later showed good passage through the bypass without evidence of extrinsic compression ( figure 2 ) . along with down syndrome and congenital heart disease , ap has been one of the most common anomalies associated with duodenal atresia or stenosis.3 with an ap , the pancreatic tissue encircling the duodenum may itself cause an extrinsic compression resulting in partial obstruction , but a duodenal atresia or stenotic web underlying the ap has often been the actual cause of blockage.4,5 in this patient , the underlying atresia or stenotic web was not evident on ugi study and partial obstruction by extrinsic compression let the patient tolerate the symptoms over a long period and thus the diagnosis was delayed . in either circumstance , bypass operation would be inevitable and therefore ap should be suspected in cases of unresolved duodenal obstruction , even in a child or adolescent . traditionally , congenital duodenal obstruction has been diagnosed with plain radiograph and contrast study is usually not required , except for differentiating midgut volvulus mimicking duodenal atresia or stenotic web . however , in the absence of complete or near - complete duodenal obstruction , plain radiograph may be insufficient to delineate classic double bubble sign . jadvar and mindelzun6 showed that contrast - enhanced act is useful in directly visualizing the complete or partial ap tissue in adults , and sandrasegaran et al7 suggested an act finding of a crocodile jaw configuration of pancreatic tissue pancreatic tissue posterolateral to the second part of the duodenum , which was suggestive of the presence of ap in adults . more recently , dusunceli atman et al8 showed the usefulness of magnetic resonance imaging in demonstrating duodenal pathology and its anatomic relationship with adjacent organs . to our knowledge , there have been no clinical clues to specifically indicate the diagnosis of ap , even for the onset at atypical age . in this patient , plain radiograph also failed to reveal duodenal obstruction , but the ugi study showed some clues on the causes of duodenal obstruction , and definite diagnosis was confirmed by act . beyond the typical age group for ap , various imaging modalities should actively be considered in patients with partial duodenal obstruction to diagnose ap . conventional surgical treatment for ap has always been bypassing the obstructed duodenum by duodenoduodenostomy , either side - to - side or diamond - shaped , to avoid major ductal structures that traverse pancreatic tissue , and many recent studies report successful results with laparoscopic approach.9 however , the duodenum is less mobile in adolescents or adults , and duodenojejunostomy or gastrojejunostomy is recommended in such cases.10 in this patient , although the laparoscopic approach failed due to the severe adhesion around the ap , the kocherized duodenum was mobile enough to allow diamond - shaped duodenoduodenostomy . we successfully diagnosed and treated an ap in an 11-year - old girl , who suffered from a long history of partial obstruction of duodenum without definite diagnosis . ugi study and act were enough to definitely delineate the ap , and duodenoduodenostomy cured the patient . although rare in childhood or adolescence , ap should be considered in patients with unresolved obstructive symptoms .
annular pancreas ( ap ) is a rare cause of congenital duodenal obstruction that is usually discovered at the neonatal period , but clinical severities can vary over a wide range and definite diagnosis could be delayed until late childhood or adulthood . 
 we report here a case of ap detected in an 11-year - old girl who had a long history of symptoms of partial duodenal obstruction . 
 upper gastrointestinal ( ugi ) study revealed narrowed second portion of duodenum by extrinsic compression , and computed tomography demonstrated complete ring of pancreatic tissue surrounding the second portion of the duodenum . 
 diamond - shaped duodenoduodenostomy successfully cured the patient , and the postoperative ugi study showed smooth passage through the bypass segment . 
 although rare , ap should be differentiated in children with unresolved symptoms of partial duodenal obstruction .