heterotopic pancreas ( hp ) is pancreatic tissue that develops in areas other than the normal site of the pancreas , having no anatomical or vascular continuity with the normal pancreas [ 1 , 2 ] .
hp of the small intestine , if enlarged , may be diagnosed due to symptoms such as ileus , bowel intussusception , melena and pancreatitis , but it often remains asymptomatic and is incidentally detected on surgery for other diseases or autopsy [ 3 , 4 ] .
we encountered 2 patients with jejunal hp incidentally detected by computed tomography ( ct ) performed for close evaluation of other diseases .
these cases are presented with a review of the literature , particularly focusing on ct findings .
case 1 was a 57-year - old woman who had been under antihypertensive medication for a few years .
when she consulted a local physician due to epigastric and back pain , a tumoral lesion 30 mm in diameter was detected on the dorsal portion of the pancreas head on abdominal ultrasonography , and the patient was referred to our hospital .
the mass was suspected to be schwannoma , castleman disease , malignant lymphoma or reactive lymphoid hyperplasia by imaging studies including ct and magnetic resonance imaging .
the contrast of the mass was nearly homogeneously enhanced in the arterial phase , and enhancement was sustained in the equilibrium phase , suggesting a submucosal tumor ( fig .
double contrast intestinal imaging showed a defect of about 14 mm in diameter in the jejunum , and a gently elevated submucosal mass with a smooth mucosal surface was confirmed by subsequent capsule endoscopy ( fig .
diseases including gastrointestinal stromal tumor and leiomyoma were suspected preoperatively , and laparotomy was performed to simultaneously remove the masses in the head of the pancreas and small intestine .
the mass in the head of the pancreas was intraoperatively suspected to be disadherable , with enlarged # 8p and # 13a lymph nodes , and was eventually diagnosed by histopathological examination as reactive lymphoid hyperplasia .
also , a tumor 15 mm in diameter was noted in the jejunum 15 cm anally from the ligament of treitz , and an about 10 cm segment of the jejunum was resected with the tumor .
it was histopathologically diagnosed as heinrich type 1 hp mainly occupying the submucosa to the muscular layer ( fig .
case 2 was an 87-year - old woman who presented with fecal occult blood on a health screening and was referred to our hospital .
blood tests indicated anemia with a hb level of 9.1 g / dl ( normal 12.016.0 ) . as for tumor makers , cea was elevated to 8.4 ng / ml ( normal 05.0 ) and p53 antibody to 3.44 ng / ml ( normal 05.0 ) .
colonic fiberscopy showed type 2 adenocarcinoma occupying two thirds of the circumference of the sigmoid colon .
ct disclosed a mass about 15 mm in diameter in the jejunum in addition to a sigmoid colon tumor accompanied by swollen lymph nodes in the neighboring regions .
the image of the jejunal mass was homogeneously contrasted in the atrial phase , and contrast enhancement persisted in the equilibrium phase , suggesting a submucosal tumor ( fig .
double contrast intestinal imaging showed a gently elevated semispherical mass 14 mm in diameter with a smooth mucosal surface near the ligament of treitz .
surgery was performed under laparoscopic guidance to resect the sigmoid colon cancer and jejunal submucosal tumor .
after sigmoid colectomy ( double stapling technique , d3 ) , a tumor 15 mm in diameter was found in the jejunum 5 cm anally from the ligament of treitz and was removed by wedge resection .
it was diagnosed histopathologically to be heinrich type 1 hp seated mainly in the submucosa .
ct images were obtained by using multi - detector row ct ( mdct ) scanner ( lightspeed vct , ge healthcare ) in both patients .
both patients received the contrast agent moiopamin 300 ( dose 100 ml ) through the median cubital vein .
the arterial and equilibrium phases were approximately 35 and 120 s , respectively , after the start of injection .
retrospectively , the ct values of the hp tissue and pancreatic parenchyma were calculated in both phases . in the region of interest in the pancreatic parenchyma , ct values
were measured at three points in the body of the pancreas by avoiding pancreatic ducts and vessels , and the mean was calculated .
concerning hp , the region of interest was determined around the mass in the axial plane that provided the largest image of the mass on ct .
the ct values in hp and the pancreatic parenchyma were106 and 100 hu , respectively , in the arterial phase and 101 and 75 hu , respectively , in the equilibrium phase . in case 2 ,
the ct values in hp and the pancreatic parenchyma were 124 and 122 hu , respectively , in the arterial phase and 91 and 77 hu , respectively , in the equilibrium phase .
the ct values of hp and pancreatic parenchyma were nearly identical in the arterial phase , but in the equilibrium phase , contrast enhancement persisted longer in hp than in the pancreatic parenchyma .
hp lacks both anatomical and vascular continuity with the main body of the pancreas and occurs anywhere from the esophagus to the rectum [ 1 , 2 ] .
the incidence of hp varies widely and has been reported in 0.65.6% of autopsy cases and in 0.2% of upper abdominal laparotomies .
the distribution of the sites of hp was 30.3% in the duodenum , 26.5% in the stomach , 16.3% in the jejunum , 5.8% in the ileum and 5.3% in meckel diverticulum , indicating that it occurs more frequently near the normal site of pancreatogenesis to the jejunum .
these lesions are usually clinically silent but may become symptomatic because of complications such as pancreatitis , obstruction , bleeding or malignant transformation [ 3 , 4 ] .
a review of the literature reveals that the significance of hp symptoms is related to the size and mucosal relation of the lesion . in a review of 34 histologically confirmed cases
, these authors concluded that lesions associated with signs and symptoms are > 1.5 cm in maximum diameter and are adjacent to or directly involve the mucosa .
a definitive hp diagnosis may be established on the basis of histological examination , which additionally allows confirmation of the histological type of hp .
heinrich 's classification is commonly accepted , being as follows : type 1 ( all elements of a normal pancreatic gland ) , type 2 ( pancreatic gland devoid of pancreatic islet cells ) , and type 3 ( only pancreatic ducts are present ) .
also , there had been no report of delineation of asymptomatic and small jejunal hp = 1.5 cm in diameter by preoperative ct before our cases . on the other hand ,
ct findings of hp in the stomach and duodenum have recently been reported [ 7 , 8 , 9 , 10 ] .
ct findings of hp in the stomach or duodenum are usually nonspecific and can not distinguish hp from other submucosal tumors .
however , ct with arterial , portal and equilibrium phase iv contrast may demonstrate the lesions which enhance similarly with the normal pancreatic tissue .
kim et al .   reported that hp with predominantly pancreatic acini shows a homogeneous enhancement pattern , whereas lesions with a mixed composition of acini and cystic ducts show a heterogeneous enhancement .
the lesions in both of our patients corresponded to heinrich type 1 with no ductal dilation or fat deposition , and showed homogeneous enhancement similarly to the pancreatic parenchyma in the arterial and equilibrium phases on ct .
however , the ct value of the jejunal hp was nearly identical with that of the pancreatic parenchyma in the arterial phase , but was higher in the equilibrium phase in both patients .
the cause of the difference in the ct value in the equilibrium phase is unknown , but it may reflect not only the difference in the composition of hp tissue but also atrophy , fibrosis and fat degeneration of the pancreatic parenchyma . as gastric or duodenal
hp is difficult to differentially diagnose from other submucosal tumors such as leiomyoma , carcinoid and gastrointestinal stromal tumor by the contrast enhancement pattern on ct or morphology alone , hp of the small intestine is difficult to differentiate from other diseases by ct alone .
the detection rate of hp of the small intestine is expected to increase with the future spread of mdct . with increasing case numbers , contrast patterns in particular phases
will be evaluated under appropriate conditions , and mdct may contribute to the differential diagnosis of hp of the small intestine .
particularly , when it is detected intraoperatively , the judgment is difficult as there is no preoperative informed consent for its resection .
since the possibility of its canceration is extremely low and as it grows very slowly , preventive resection has been reported to be unnecessary [ 11 , 12 ] .
recently , however , there have been a number of reports of its resection due to melena , ileus , intussusception , etc . even without canceration , and many authors support aggressive resection of resectable hp . in our cases , jejunal hp was detected incidentally during examination for other diseases , and the presence of submucosal masses could be confirmed preoperatively by fluoroscopy and endoscopy of the small intestine .
this made it possible to obtain sufficient informed consent from the patients to remove the intestinal submucosal tumor as well as the primary disease and to perform surgery safely .
this report presented 2 cases of jejunal hp incidentally detected by ct during examination for other diseases . the frequency of incidental detection of intestinal submucosal tumors is expected to increase with a rise in the frequency of mdct use . while most small lesions of hp are asymptomatic , it may be complicated by ileus and intussusception , and hp is considered to be an important disorder that should be recognized along with gastrointestinal stromal tumor , carcinoid , etc .
 heterotopic pancreas ( hp ) is typically an asymptomatic malformation that can present anywhere along the gastrointestinal tract . 
 it is often detected incidentally on surgery for other diseases or autopsy . 
 we encountered 2 patients with jejunal hp incidentally detected by computed tomography ( ct ) performed for close evaluation of other diseases . in a 57-year - old woman diagnosed with reactive lymphoid hyperplasia on the dorsal portion of the pancreas head , ct detected a 15 mm oval - shaped submucosal lesion at the jejunum . in an 87-year - old woman 
 diagnosed with type 2 adenocarcinoma occupying the sigmoid colon , ct detected a round - shaped submucosal tumor 15 mm in diameter in the jejunum . 
 both cases were histologically diagnosed as type 1 hp according to the classification by heinrich . 
 contrast - enhanced ct revealed that the ct analyses of hp and pancreatic parenchyma were nearly identical in the arterial phase , but in the equilibrium phase , contrast enhancement persisted longer in hp than in the pancreatic parenchyma . 
 there has been no report of asymptomatic jejunal hp preoperatively diagnosed by ct . 
 these cases are presented with a review of the literature , particularly focusing on ct findings . 
Introduction
Case Reports
Discussion