Park et al. investigated the morphologic features of 26 patients with ectopic pancreas, and they observed umbilication or central dimpling in 34.6% (9/26 lesions) . In endoscopic ultrasonography examination, 92.3% (24/26) of the lesions showed hypoechoic echogenicity, and 50.0% (13/26) were heterogeneous. Moreover, an anechoic duct-like structure was detected in 65.4% (17/26) of the tumors. On the basis of the sonographic layer of origin, 53.8% (14/26) of the tumors were found in the submucosal and proper muscle layers with or without extension into the subserosal or serosal layer, whereas the remaining 46.2% (12/26) of the tumors were located in the deep mucosal and/or submucosal layers. In the present patient, ectopic pancreas was the most likely diagnosis, because of the anatomic location and the hypoechoic echogenicity.
Lymph node metastatic infiltration was not identified. This paper reports the first, to our knowledge, case of endoepithelial carcinoma arising in a gastric heterotopic pancreas of a 56-year old woman in Greece. He felt well for four months and then developed recurrent mild, diffuse, sharp, steady abdominal pain. He denied weight loss, nausea, vomiting, or bowel complaints. Physical examination showed normal vital signs, afebrile.
For a carcinoma to be described as arising from heterotopic pancreatic tissue, three criteria have been proposed [16,12]. Firstly, the tumor must be found within, or close to the aberrant pancreatic tissue. Secondly, the transitional area between pancreatic structures and carcinoma must be observed (i.e. duct-cell dysplasia and/or carcinoma in situ). Thirdly, the non-neoplastic heterotopic pancreatic tissue must comprise of at least fully developed acini and/or ductal structures.
Epigastric CT revealed a duodenal bulb submucosal lump that showed exophytic growth, which was possibly a benign GIST. Gastroscopy revealed chronic atrophic gastritis.
They commonly arise from the third and fourth layers.61 However, lesions may develop in any location from the deep mucosal to the serosal layer. A, Endoscopic image of an indistinct submucosal lesion. B, Corresponding EUS image showing an ill-defined, slightly hypoechoic, inhomogeneous mass involving the third and fourth gastric layers. On endoscopy, an aberrant pancreas appears as a submucosal nodule, usually small, with a characteristic central umbilication that corresponds to a draining duct. The characteristic EUS features of aberrant pancreas are heterogeneous lesions, mainly hypoechoic or intermediate echogenic masses accompanied by scattered small hyperechoic areas, with indistinct margins within the gut wall (Fig. 10.5 ).
The diagnosis of a submucosal mass lesion in the upper gastrointestinal tract with normal overlying mucosa on endoscopy can be divided into benign and malignant etiologies. Benign lesions include leiomyoma, lipoma, varices, neural tumors (i.e., schwannoma, neuroma, or neurofibroma), granular cell tumor, inflammatory fibroid polyp, duplication cyst, lymphangioma, Brunner’s gland hyperplasia, benign GIST, and heterotopic pancreas.
(A) Endoscopic image of an indistinct submucosal lesion. (B) Corresponding endoscopic ultrasound image showing an ill-defined, slightly hypoechoic inhomogeneous mass involving the third and fourth gastric layers.
Thinking of peptic ulcer she was given proton pump inhibitors which showed no response. Ultrasound abdomen performed was unremarkable. CT abdomen with oral and IV contrast was advised due to her persistent symptoms.
2b ). Immunohistochemically, the pancreatic tissue was negative for p53 and Ki-67 labeling was 1.2%. Several theories have been proposed to explain the pathogenesis and occurrence of pancreatic heterotopia. The most tenable theory implicates that during the development of normal pancreas from several evaginations, originating from the wall of the primitive duodenum, one or more evaginations may remain in the bowel wall.
Delayed or missed diagnosis is frequent [2, 10]. Factors implicated include (1) diverse, nonspecific complaints ranging from mild to severe, which may be indistinguishable from more common infectious, inflammatory, or neoplastic diseases [8, 9]; (2) rarity of clinical expression limits diagnostic suspicion of this entity [1, 4, 6]; (3) location in the submucosa or muscularis, typically with normal overlying mucosa, hampers diagnosis by standard endoscopy or imaging [4, 7]; (4) macroscopic appearance of heterotopic pancreas is pleomorphic , and it can be confused with a myriad of submucosal mass lesions; (5) classic endoscopic appearance of an antral submucosal bulge, which may contain a “crater-like” central umbilication corresponding to a draining duct, is absent in 50-80% of cases [1, 8]; (6) inflamed ectopic pancreatic tissue rarely produces sufficient enzymes to elevate serum amylase or lipase above normal . Heterotopic pancreas, also known as ectopic pancreas, is pancreatic tissue located outside the pancreatic parenchyma without vascular or ductal communication with the gland. Ectopic pancreas is rarely symptomatic, typically detected incidentally at surgery or autopsy. Eighty-five to 90% are in the upper GI tract, especially the gastric antrum.
Ectopic pancreatic tissue or heterotopic pancreatic tissue, refers to the presence of pancreatic tissue in the submucosal, muscularis or subserosal layers of the gastrointestinal tract outside the normal confines of the pancreas. There is no anatomical or vascular connection with the main pancreas . It can be named as aberrant, accessory pancreas, or sometimes called as pancreatic choristoma and adenomyoma. It is difficult to determine the true incidence as usually patients are asymptomatic and it is detected on autopsy. A prevalence rate of 0.5%–13.7% is quoted in autopsy results, 0.2% in upper abdominal surgeries as incidental finding and 0.9% of gastrectomies [2,3].
Her medical history included a reflux esophagitis with a hiatal hernia and hypothyroidism under medical treatment. On esophagogastroduodenoscopy, an ulcerated lesion in the gastric antrum was found, biopsy specimens of which showed intense epithelial dysplasia with incipient malignant degeneration (Fig. (Fig.1). 1 ). The physical examination and all the laboratory findings were normal. The tumor markers including CEA (1.3 ng/mL), aFP (4.4 ng/mL), CA-19-9 (2.9 u/mL), CA-125 (4.74 u/mL) and CA-72-4 (3.1 u/mL) were within normal ranges.
They commonly arise from the third and fourth layers.42 However, lesions may develop in any location from the deep mucosal to the serosal layer. FIGURE 53.7 .
Ectopic pancreas is rarely symptomatic. The vast majority of lesions are detected incidentally at surgery or autopsy. Barbosa and colleagues reported approximately 1 incidental case detected per 500 upper abdominal operations; the incidence for all autopsies was 1.7% [1, 2]. Other sources cite an overall incidence of 0.2-0.8% in surgical patients and 0.6-14% of autopsy cases [3–6]. Eighty-five to 90% are found in the upper GI tract, especially the gastric antrum and duodenum [4, 5].
Perforation occurred in two patients (2/37, 5.4%), bleeding in one (1/37, 2.7%), and pneumoperitoneum in three (3/37, 8.1%). Catalano et al. reported on the use of ESD for 20 patients with submucosal tumors; R0 resection was done in 90.0% of the patients (18/20). Though perforation occurred in three cases (15%), no patients experienced severe bleeding .
They contained a mixture of pancreatic acini, ducts and islets of Langerhans. The overlying gastric mucosa was normal. Patients with heterotopic pancreas can be normal, or present with abdominal pain and distension. In addition, it can manifest clinically in some rare diseases of the pancreas including pancreatitis, islet cell tumor, pancreatic carcinoma, and pancreatic cyst.
The patient presented with a submucosal tumor in the gastric antrum. The tumor was suspected to be ectopic pancreas, but the possibilities of neuroendocrine tumor or other histologic entities could not be excluded. A total biopsy by the endoscopic submucosal dissection (ESD) technique was performed, and the diagnosis of ectopic pancreas was made.
The second and third cases seem to be heterotopic pancreatic tissues of congenital anomalies. Yamagiwa et al.  suggested that Heinrich type I heterotopic pancreas of the stomach was caused by immigration from fetal pancreas, while Heinrich type II and III heterotopic pancreas arises through erroneous differentiation of primitive gastric mucosal epithelium. However, their hypothesis lacks evidence. The frequency of heterotopic gastric mucosa is different depending on the examinations employed. According to Yamagiwa et al. , heterotopic pancreas was present in 107 cases among the 5,446 surgically resected stomachs, the incidence being 1.2%.
Histopathology came out to be heterotrophic pancreatic rest rather than neoplastic lesion (Figures 4 & 5). Open gastric antrectomy with a Billroth I technique was performed for a preoperative diagnosis of gastric adenocarcinoma. Histology of the resected specimen revealed ectopic pancreatic tissue, including excretory ducts, acini, and islet cells within the gastric muscularis layer (Figure 3). Evidence of chronic pancreatitis was present, including fibrosis and dilated ducts containing proteinaceous material.
Therefore, we consider ESD as a treatment option for ectopic pancreas in the stomach, particularly for symptomatic cases or cases with atypical morphological features. Although it has been thought that the en bloc resection of submucosal tumors originating from the proper muscle layer has an increased risk of perforation and bleeding , Białek et al. and Catalano et al. concluded that ESD is effective and relatively safe for resecting gastric submucosal tumors of proper muscle origin [4, 30].
Heterotopic pancreas may manifest some symptoms of carcinoid syndrome, and surgical treatment may eliminate such symptoms. Asymptomatic heterotopic pancreas is hard to diagnose. The treatment of asymptomatic histologically verified gastric heterotopic pancreas is debatable.
Therefore, we applied genetic analysis to identify KRM for the purpose of confirming our diagnosis and speculating on its possible histogenesis. Pancreatic carcinoma has the highest incidence of KRM among various human cancer tissues. Many investigators have reported the presence of KRM in this carcinoma at higher rates, ranging from 75% to 100% (Almoguera et al., 1988) . Moreover, the KRM found in our study is the most common type of change observed in the patients with pancreatic carcinoma.
The histogenesis of heterotopic pancreatic tissue is controversial. In my opinion, the present first case is a true heterotopic pancreas of congenital abnormality.
In conclusion, we treated a patient with ectopic pancreas in the stomach. A histologic diagnosis was made by ESD in our patient. Resection by an ESD technique is a viable option for the pathological diagnosis of gastric submucosal tumors. Heterotopic pancreas is usually asymptomatic, but may become clinically evident depending on the size, location and pathological changes . Lesions larger than 1.5 cm in diameter are more likely to cause pain.
Complications include GI bleeding, acute or chronic pancreatitis, pancreatic necrosis, pseudocyst, gastric outlet obstruction, perforation, and, rarely, pancreatic carcinoma. This rare disorder mimics more common diseases. Low suspicion, nondiagnostic imaging or endoscopy contribute to frequent diagnostic delay. Context Heterotopic pancreas is the presence of pancreatic tissue found outside the usual anatomical location of the pancreas. It is a rare condition and can occur anywhere in the gastrointestinal tract with the stomach and the small bowel being the most common sites.
She underwent an esophagogastroduodenoscopy which showed a sessile mass in the gastric antrum with apparently normal covering mucosa (Figure 1).The endoscopic diagnosis was a sessile antral polyp. The esophagus and duodenum were unremarkable.
Distal small bowel, omental, or mesenteric locations are less common . Involvement of the mediastinum, lungs, liver, gallbladder, spleen, esophagus, fallopian tubes, or Meckel’s diverticulum is very rare . Gastric heterotopic pancreas has been reported to be submucosal in about three-quarters of cases and is located in the muscularis propria or subserosa in the remaining cases [4, 7].
6. Heterotopic pancreatic ducts located within the muscularis propria (H-E × 6). Gross features of the surgically resected specimen of the distal gastrectomy were of an ulcerated lesion in the gastric antrum, adjacent to the lesser curvature of the stomach, which measured 2 × 1.2 cm, with smooth edges.
It may become clinically evident when complicated by pathological changes such as inflammation, bleeding, obstruction, and malignant transformation. In this report, a 60-year-old man with carcinoid syndrome caused by heterotopic pancreatic tissue in the duodenum is described, along with a 62-year-old man with abdominal pain caused by heterotopic pancreatic tissue in the gastric antrum. The difficulty of making an accurate diagnosis is highlighted. The patients remain healthy and symptom-free after follow-up of 1 year.
The first case appears to be a true heterotopic pancreas of congenital abnormality. The second and third cases seem to be heterotopic pancreatic tissues of congenital anomaly of the gastric mucosa. The histogenesis of heterotopic pancreatic tissue is discussed. Ectopic pancreas is defined as pancreatic tissue found outside the usual anatomic location of the pancreas. It is often an incidental finding and can be found at different sites in the gastrointestinal tract.
However, pediatric patients may be affected as well.126 Heterotopic pancreatic tissue is susceptible to many of the same inflammatory disorders that affect the native pancreas, including acute and chronic pancreatitis and cancer,126–128 although the latter complication is extremely uncommon. There have been reports of clinical symptoms associated with large (more than 1.5 cm) pancreatic rests.194 The most common symptoms were abdominal pain, dyspepsia, and gastrointestinal bleeding. Biliary and pyloric obstruction may occur.195 Pancreatitis in the ectopic tissue has also been described, and there are reported cases of cancer occurring in the ectopic pancreas.196 Because ectopic pancreatic tissue is usually asymptomatic, management is usually observational with operative treatment reserved for complicated cases.197 The submucosal location of pancreatic rests makes endoscopic removal unattractive, owing to the perforation risk.
A 26 year old female presented in outpatient clinic during her second trimester of pregnancy with complaints of daily regular epigastric pain with off and on vomiting. The pain started during pregnancy 2 months back.
Asymptomatic lesions do not necessarily require resection and can be followed expectantly. If needed, endoscopic removal is useful for both accurate diagnosis and treatment, although surgical resection is preferred to endoscopic resection when the muscularis propria is involved. (Courtesy Dr. Kathryn McKenzie, Edinburgh.) Investigation and diagnosis again depend on the mode of presentation. In a contemporary series, diagnosis was made at gastroduodenoscopy in 36% and at surgery in 64% (Eisenberger et al, 2004 ). It was noted that definitive diagnosis was only obtained with histologic assessment.
We report a case of a 40-year-old female with an ectopic pancreatic lesion in the antrum of the stomach. A 62-year-old man complained of repeated, vague right upper quadrant pain for 2 years. Physical examination and laboratory findings were unremarkable. Endoscopy showed a solid tumor mass in the gastric antrum (Figure (Figure1).
Further, the author investigated the fetal development of intrahepatic bile ducts [22,23,24,25,26,27], and discovered that intrahepatic bile ducts frequently differentiated into pancreatic acinar cells in the fetal period. These observations highly suggest that clusters of pancreatic acinar cells are congenital in origin. In conclusion, although pancreatic heterotopia is rare, it should be always considered in the differential diagnosis of extramucosal gastric lesions.