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portal annular pancreas ( pap ) is a rare variant in which the uncinate process of the pancreas extends to the dorsal surface of the pancreas body and surrounds the portal vein or superior mesenteric vein ( smv ) .
recent progress has made it possible to diagnose pap preoperatively with contrast - enhanced multidetector computed tomography ( mdct ) or magnetic resonance imaging .
nevertheless , pap is still not recognized as an important finding in cases of pancreas cut surface reconstruction .
most cases of pap have been reported during pancreaticoduodenectomy ( pd ) [ 1 , 2 , 3 , 4 , 5 ] . upon pd , when the pancreas is cut at the neck , which is located at the left side of the portal vein , two cut surfaces of the pancreas are created .
thus , the cut surface of the pancreas becomes larger than usual and the dorsal cut surface is behind the portal vein , therefore pancreatic fistula after pd has been reported frequently [ 2 , 5 ] .
here , we report a patient with pap who underwent subtotal stomach - preserving pd ( ssppd ) and additional pancreas resection 1 cm distal to the pancreas tail to the left side of the original resection line . this allowed us to perform safe pancreatic jejunal anastomosis .
her unconsciousness was due to hypoglycemia and she recovered quickly after intravenous administration of glucose . for about 2 years , she had been aware of palpitations , cold sweat and nausea that improved after consuming sweets during exercise .
she was admitted to the department of surgery and science , kyushu university with suspicion of insulinoma of the pancreas head .
complete blood cell count was normal ; immunoreactive insulin level was 178 u / ml and fasting blood sugar 56 mg / dl .
serum levels of glucagon , gastrin , growth hormone , adrenocorticotropic hormone , thyroid - stimulating hormone and free t4 were within normal limits .
the tumor markers pro - gastrin - releasing peptide , neuron - specific enolase , carcinoembryonic antigen and carbohydrate antigen 19.9 were also within normal limits .
on contrast - enhanced mdct , an enhanced 2-cm nodule was detected in the pancreas head .
when the pancreas head was dissected at the usual level , which was to the left of the portal vein , the uncinate process was extended and fused to the dorsal surface of the pancreas body .
pancreatic duct - like structures were observed in the usual place and the extended uncinate process .
reconstruction of the pancreas cut surface seemed to be difficult , and additional resection of the pancreas body 1 cm distal to the pancreas tail to the left side of the original resection line was performed . on the new cut surface ,
there was only one pancreatic duct in the usual place and pancreaticojejunostomy was performed as usual .
after the operation , mdct revealed an extended uncinate process of the pancreas that was fused to the dorsal surface of the pancreas body by surrounding the portal vein ( fig .
no postoperative complications such as pancreatic fistula occurred , and the patient was discharged from hospital on day 22 after the operation .
pap is an anatomical variant in which the uncinate process extends and joins the dorsal area of the pancreas body .
the portal vein and/or the smv are surrounded by the uncinate process of the pancreas .
reviewed 700 abdominal contrast - enhanced mdct scans , irrespective of the patients ' disease and sex , and diagnosed 8 cases ( 1.14% ) of pap .
there are no clinical symptoms related to pap , and it emerges only when operative intervention is required .
proposed another pap classification that categorizes cases according to the location of the main pancreatic duct .
the main pancreatic duct is posterior to the portal vein because the ventral bud of the pancreas fuses with the dorsal area of the pancreas body in type i pap .
type ii pap is associated with pancreas divisum and the main pancreatic duct is posterior to the portal vein .
type iii pap is when the uncinate process alone is involved in encasement of the portal vein and/or smv .
sugiura et al .   reported the first case of pap in 1987 . to the best of our knowledge ,
5 cases of pap in patients who have undergone pd have been reported to date [ 1 , 2 , 3 , 4 , 5 ] .
reconstruction of the pancreas cut surface in pd is difficult and crucial in pap for the following reasons : ( 1 ) the cut surface of the pancreas is larger than usual , ( 2 ) the dorsal cut surface of the pancreas is located in the dorsal portal vein , and ( 3 ) a pancreatic duct can be observed in the uncinate process .
the standard operative procedure for reconstruction of the pancreatic cut surface in pap has not been determined to date .
sugiura et al .   closed the pancreas cut surface by suture when it was dorsal to the smv .
divided the fused region of the uncinate process and dorsal area of the pancreas body .
pancreatic fistula occurred in 2 of 4 cases with pd that had information about postoperative complications .
closure of the dorsal cut surface by suture should be avoided in patients with type i and ii pap according to the classification of joseph et al . , because the main pancreatic duct is located at the dorsal cut surface .
even when the main pancreatic duct is found at the dorsal pancreas cut surface in patients with type i and ii pap , anastomosis of the pancreatic duct and jejunum is technically difficult because fine anastomosis has to be done behind the portal vein .
additional resection of the pancreas body to the left of the original resection line seems to be reasonable and can make the cutting surface the same as usual anatomically , although this method has not been reported previously . by adding further resection , only one pancreatic duct
according to karasaki et al . , the mean length of the fusion between the lingual projection and the body of the pancreas was 9.4 mm , therefore an additional 1-cm resection of the pancreas body may be sufficient for safe anastomosis ( fig .
, additional resection of the pancreas body may be a standardized procedure in patients with pap who are undergoing reconstruction of the pancreas cut surface .
portal annular pancreas ( pap ) is a rare variant in which the uncinate process of the pancreas extends to the dorsal surface of the pancreas body and surrounds the portal vein or superior mesenteric vein . upon pancreaticoduodenectomy ( pd ) , when the pancreas is cut at the neck , two cut surfaces are created . 
 thus , the cut surface of the pancreas becomes larger than usual and the dorsal cut surface is behind the portal vein , therefore pancreatic fistula after pd has been reported frequently . 
 we planned subtotal stomach - preserving pd in a 45-year - old woman with underlying insulinoma of the pancreas head . when the pancreas head was dissected , the uncinate process was extended and fused to the dorsal surface of the pancreas body . 
 additional resection of the pancreas body 1 cm distal to the pancreas tail to the left side of the original resection line was performed . 
 the new cut surface became one and pancreaticojejunostomy was performed as usual . 
 no postoperative complications such as pancreatic fistula occurred . 
 additional resection of the pancreas body may be a standardized procedure in patients with pap in cases of pancreas cut surface reconstruction .