pancreatic heterotopia is defined as the presence , outside its usual location , of pancreatic tissue which lacks anatomical and vascular continuity with the pancreas proper ( 1 ) .
the heterotopic pancreas ( hp ) is a relatively uncommon congenital anomaly , with an incidence between 0.55% and 13.7% in autopsy series and mean frequency between 1 and 2% .
hp has been found in all age groups , predominantly in the sixth decade of life ( 2 ) .
the usual locations of hp are in the stomach in 25 - 38% cases , the duodenum in 17 - 36% and the jejunum in 15 - 22% of cases .
it is usually silent but it may become clinically evident when complicated by inflammation , bleeding , obstruction or malignant transformation ( 3 ) .
symptomatic patients require surgical exploration in order to obtain a definitive diagnosis and to exclude malignancy .
a 12 years old male child presented with severe abdominal pain and intermittent vomiting , not relieved with medications .
usg showed telescopy of gut loop along with its mesentry into other infraumblical region at the level of anterior superior iliac spine suggestive of ileoileal intesusception .
an ileal polyp was found to be the cause of intussusceptions which was removed along with small segment of adjacent bowel and sent for histopathological examination .
surgical specimen of resected ileal polyp with adjacent bowel loop ( 1a ) cut surface of which was pale yellow ( 1b ) .
histological examination revealed presence of pancreatic tissue in muscularis propria of ileum ( 1c ) ( h&e , x40 ) with overlying mucosa showing congestion and metaplasia ( 1d ) ( h&e , x40 ) on gross examination , the polyp was brown , oval sessile mass with a broad base measuring 63.52 cm ( fig .
the histological examination revealed the presence of pancreatic tissue in the muscularis propria of ileum ( fig .
1c ) made up of pancreatic acini and dialated ducts interspersed by smooth muscle bundles ( fig .
photomicrograph showing pancreatic acini and ducts ( h&e , x100 ) the patient had an uneventful recovery and remains asymptomatic postoperatively .
as stated by hunt and bonesteel ( 5 ) the first case of heterotopic pancreas was reported by schultz in 1729 , and klob provided its histological confirmation in 1859 ( 6 ) .
the reported incidence in autopsy studies is 0.5 - 13% ( 3 ) . in adults
it is found mainly in the stomach , duodenum and jejunum , in much smaller proportions in the ileum and meckel s diverticulum , and it is rarely found in the esophagus , liver , gallbladder , omentum , lungs , mediastinum , fallopian tubes and umbilicus ( 2 ) . in adults the incidence is higher in males , while in pediatric patients the female gender prevails .
the proposed theory is that during rotation of foregut in a fetus and fusion of dorsal and ventral parts of pancreas , small islands of pancreas are carried away and continue to develop at its aberrant location ( 2 ) .
most patients with ectopic pancreas are asymptomatic and diagnosis is usually performed during radiological examination or endoscopy of the digestive tract or during surgical explorations motivated by other diseases ( 2 ) . when symptomatic , about 30% of total mimic clinical symptoms similar to diseases that affect the organ in which the heterotopia is located ( 3 ) .
usually they present in the form of small yellowish nodules , ranging from 1 mm to 5 cm , typically covered by intact mucosa , and often exhibit a central hole representing exteriorization of the rudimentary pancreatic duct .
however , lesions smaller than 1.5 cm do not usually show such an orifice ( 8) . the ectopic pancreatic tissue is detected more frequently in the submucosa and muscularis propria layers of the gastrointestinal tract and may be observed in the sub - serosa or even in the serosa of the affected segment ( 2 ) .
the heinrich classification system is frequently used to classify heterotopic pancreas : type 1 ( containing acini , islets and ducts ) , type 2 ( acini and ducts , no islets ) and type 3 ( ducts alone ) ( 9 ) .
the preoperative imaging studies ( ultrasonography , endoscopic ultrasonography and computerized tomography ) are not very specific ( 3 ) .
hence , in the majority of cases , the diagnosis is made by histological evaluation following resection of a symptomatic or suspicious lesion ( 10 ) .
the management of asymptomatic , histologically verified heterotopic pancreas or those found incidentally during other surgery is under debate .
although , in the majority of the cases of heterotopic pancreas reported surgical resections were done ; endoscopic mucosal removal can be an attractive , less invasive option for the resection of accessible lesions ( 3 ) .
although there have been studies describing clinicopathological analysis of patients presenting with heterotopic pancreas(2,10 ) , ileal heterotopic pancreas has been rarely reported in children .
heterotopic pancreas is a rare congenital lesion , often diagnosed incidentally on histopathological examination and should be considered in the differential diagnosis of intestinal mass lesions .
 heterotopic , aberrant or ectopic pancreas is defined as the presence of pancreatic tissue in topographic anomaly , with no anatomical , neural or vascular connection to the normal pancreas . it is a rare condition found mainly in stomach , duodenum and jejunum . 
 ileal heterotopic pancreas is an uncommon condition and has been rarely reported in children so far . 
 hereby we report a case of heterotopic pancreas presenting as ileal poyp leading to ileoileal intussusception in a 12 year child . 
INTRODUCTION
CASE REPORT
DISCUSSION