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 Table of Contents  
Year : 2013  |  Volume : 2  |  Issue : 3  |  Page : 168-170

A retroperitoneal neuroendocrine tumor in ectopic pancreatic tissue

1 Internal Medicine Gastroenterology and Hepatology, Cairo, Egypt
2 Department of Surgery, Cairo University, Cairo, Egypt
3 Department of Surgery, National Cancer Institute, Cairo, Egypt
4 Department of Cytopathology Unit, National Cancer Institute, Cairo, Egypt
5 Department of Gastroenterology, Assiut University, Cairo, Egypt

Date of Submission30-May-2013
Date of Acceptance01-Sep-2013
Date of Web Publication6-Sep-2013

Correspondence Address:
Hussein Hassan Okasha
Internal Medicine Gastroenterology and Hepatology, Cairo
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2303-9027.117676

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Ectopic pancreas is the relatively uncommon presence of pancreatic tissue outside the normal location of the pancreas. We report a case of abdominal pain due to retroperitoneal neuroendocrine tumor arising from heterotopic pancreatic tissue between the duodenal wall and the head of the pancreas. Patient underwent surgical enucleation of the tumor.

Keywords: ectopic pancreas; neuroendocrine tumor; endoscopic ultrasonography; retroperitoneal tumor

How to cite this article:
Okasha HH, Al-Bassiouni F, El-Ela MA, Al-Gemeie EH, Ezzat R. A retroperitoneal neuroendocrine tumor in ectopic pancreatic tissue . Endosc Ultrasound 2013;2:168-70

How to cite this URL:
Okasha HH, Al-Bassiouni F, El-Ela MA, Al-Gemeie EH, Ezzat R. A retroperitoneal neuroendocrine tumor in ectopic pancreatic tissue . Endosc Ultrasound [serial online] 2013 [cited 2020 Jun 7];2:168-70. Available from: http://www.eusjournal.com/text.asp?2013/2/3/168/117676

  Introduction Top

Ectopic pancreas (EP) is the relatively uncommon presence of pancreatic tissue outside the normal location of the pancreas. This condition is usually asymptomatic and rarely complicated by pancreatitis or malignant transformation. It is defined as pancreatic tissue abnormally situated, without connection to the normal pancreas, but provided with its own vascular and ductal systems. [1] EP tissue has been found in both abdominal and extra abdominal locations, but is most frequently encountered in the stomach (25%-60%), [2] duodenum (25%-35%) [2] and rarely in mesocolon [3],[4] and Meckel's diverticulum. [5] Other terms such as heterotopic and aberrant pancreas have also been described in the literature. [6] Retroperitoneal, EP tissue appearing as bilateral suprarenal masses has been reported once in 2009 [7] but a neuroendocrine tumor (NET) in a retroperitoneal EP tissue has not been reported before. Gaspar Fuentes et al. modified von Heinrich's classification of pancreatic heterotopias. [8],[9] Type I was total pancreatic heterotopia with all pancreatic cell types present, Type II is composed of pancreatic ducts only (the so called canalicular variety), Type III comprises acinar tissue only (exocrine pancreas) and Type IV is made up of islet cells only (endocrine pancreas). The histological classification of the heterotopic pancreas in our case is Type I because all elements were present, although the epithelial component dominated and less frequently the ductal component.

The origin of EP tissue is unknown; it is possible that during rotation of the foregut and fusion of the ventral and dorsal parts of the pancreas in early fetal life, small pieces of tissue become detached from the forming organ leading to entrapment in different locations. [10]

  Case Report Top

A 72-year-old male was presented by dull aching epigastric and right hypochondrial pain radiating to the back. He is not known to be diabetic or hypertensive. His pulse rate and blood pressure were normal. The physical examination was unremarkable, with no palpable abdominal masses. Lab investigations were normal.

Upper endoscopy revealed a smooth bulge at the mid second part of the duodenum with normal underlying mucosa, likely due to compression from outside. Abdominal ultrasound and computed tomography (CT) showed a well-defined right lumber mass in-between the second part of the duodenum and the head of the pancreas, but appears separated from them. Common bile duct and pancreatic duct are not dilated. No lymphadenopathy was found. Endoscopic ultrasound (EUS) showed a localized paraduodenal echogenic mass measuring 58 mm × 67 mm with a well-defined line of separation form the duodenal wall and the head of the pancreas [Figure 1]. It shows elasticity score 4 [11] denoting its firm consistency [Figure 2]. EUS-guided fine needle aspiration (EUS-FNA) and cell-block preparation was carried out. Histopathological examination revealed the presence of compact groups of epithelial cells having central rounded nuclei with occasional presence of nucleoli and moderate eosinophilic granular cytoplasm separated by delicate stroma showed many small vascular spaces. Immunohistochemistry revealed positive immunostaining for synaptophysin and chromogranin [Figure 3]. The decision for surgical intervention was taken. On laparotomy, a retroperitoneal well encapsulated mass was found between the wall of the duodenum and the head of the pancreas and separated from them. Enucleation of the tumor was performed and pathological examination confirmed the FNA diagnosis.
Figure 1. Endoscopic ultrasound picture of the mass

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Figure 2. Elastography of the mass (elasticity score 4)

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Figure 3. Tumor cells showing positive immunostaining for chromogranin (A) and synaptophysin (B) (×400)

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  Discussion Top

Several theories had been implicated to describe the origin of EP tissue. The most accepted one implicates migration and/or rests of branching pancreatic tissue buds from the developing pancreas during embryogenesis. This theory is most likely when one considers gastrointestinal pancreatic heterotopia; however, pancreatic tissue occurring in more exotic, anatomically remote sites, such as the thyroid gland or  Fallopian tube More Details, may have a different pathogenesis. The possibility of origin from teratomas has been advocated in these instances.

The pancreatic ectopic tissue is usually presented by gastric pain and patients may also complain of bleeding, nausea and vomiting and chest pain. The mechanism for the production of symptoms is unclear. Armstrong et al. found a correlation between the presence of symptoms, size of the lesion (greater than 1.5 cm) and extent of mucosal involvement. [12]

EP typically appears on a radiographic barium study or endoscopic examination as a submucosal mass with central umbilication. [13],[14] On CT, an EP most frequently appears as a well-defined oval or round mass with smooth or serrated margins in the gastric antral wall or intestinal wall or as a mesenteric mass similar to a gastrointestinal stromal tumor or carcinoid tumor. [13],[14],[15]

EUS is typically used to evaluate the submucosal lesions in the upper gastrointestinal tract. [16] EP usually appears hypoechoic and heterogeneous with indistinct margins during EUS and the most commonly originates from the third or fourth layer or a combination of these two layers of the gastrointestinal tract. [17] EUS also allows the use of targeted FNA biopsy, particularly helpful for the final diagnosis. Although cytological examinations are inconclusive in about 50% of cases, [10] in this case EUS-FNA gave the same result as the excisional biopsy as being NET.

We report, to our knowledge, the first case of a NET in a retroperitoneal EP tissue. Heterotopic pancreas should be considered in the differential diagnosis of a retroperitoneal masses as well as a submucosal mass of the gastric, duodenal, jejunal and esophageal wall and it has the same line of management as pancreatic NET, which is surgical resection that should remain the mainstay of treatment for patients with a localized disease.

  References Top

1.Hsu SD, Chan DC, Hsieh HF, et al. Ectopic pancreas presenting as ampulla of vater tumor. Am J Surg 2008; 195: 498-500.  Back to cited text no. 1
2.Mulholland KC, Wallace WD, Epanomeritakis E, et al. Pseudocyst formation in gastric ectopic pancreas. JOP 2004; 5: 498-501.  Back to cited text no. 2
3.Ishikawa O, Ishiguro S, Ohhigashi H, et al. Solid and papillary neoplasm arising from an ectopic pancreas in the mesocolon. Am J Gastroenterol 1990; 85: 597-601.  Back to cited text no. 3
4.Tornóczky T, Kálmán E, Jáksó P, et al. Solid and papillary epithelial neoplasm arising in heterotopic pancreatic tissue of the mesocolon. J Clin Pathol 2001; 54: 241-5.  Back to cited text no. 4
5.Koh HC, Page B, Black C, et al. Ectopic pancreatic-type malignancy presenting in a Meckel's diverticulum: A case report and review of the literature. World J Surg Oncol 2009; 7: 54.  Back to cited text no. 5
6.Mizuno Y, Sumi Y, Nachi S, et al. Acinar cell carcinoma arising from an ectopic pancreas. Surg Today 2007; 37: 704-7.  Back to cited text no. 6
7.Lin LH, Ko SF, Huang CC, et al. Retroperitoneal ectopic pancreas: Imaging findings. Br J Radiol 2009; 82: e253-5.  Back to cited text no. 7
8.Gaspar Fuentes A, Campos Tarrech JM, Fernández Burgui JL, et al. Pancreatic ectopias. Rev Esp Enferm Apar Dig 1973; 39: 255-68.  Back to cited text no. 8
9.Hammock L, Jorda M. Gastric endocrine pancreatic heterotopia. Arch Pathol Lab Med 2002; 126: 464-7.  Back to cited text no. 9
10.Tolentino LF, Lee H, Maung T, et al. Islet cell tumor arising from a heterotopic pancreas in the duodenal wall with ulceration. Exp Mol Pathol 2004; 76: 51-6.  Back to cited text no. 10
11.Giovannini M. Endoscopic ultrasound (EUS) elastography. MEDIX Supplement. Special Issue : Clinical Applications of HITACHI Real-time Tissue Elastography; 2007. p. 32-5.  Back to cited text no. 11
12.Armstrong CP, King PM, Dixon JM, et al. The clinical significance of heterotopic pancreas in the gastrointestinal tract. Br J Surg 1981; 68: 384-7.  Back to cited text no. 12
13.Mortelé KJ, Rocha TC, Streeter JL, et al. Multimodality imaging of pancreatic and biliary congenital anomalies. Radiographics 2006; 26: 715-31.  Back to cited text no. 13
14.Silva AC, Charles JC, Kimery BD, et al. MR Cholangiopancreatography in the detection of symptomatic ectopic pancreatitis in the small-bowel mesentery. AJR Am J Roentgenol 2006; 187: W195-7.  Back to cited text no. 14
15.Wang C, Kuo Y, Yeung K, et al. CT appearance of ectopic pancreas: A case report. Abdom Imaging 1998; 23: 332-3.  Back to cited text no. 15
16.Yasuda K, Cho E, Nakajima M, et al. Diagnosis of submucosal lesions of the upper gastrointestinal tract by endoscopic ultrasonography. Gastrointest Endosc 1990; 36: S17-20.  Back to cited text no. 16
17.Matsushita M, Hajiro K, Okazaki K, et al. Gastric aberrant pancreas: EUS analysis in comparison with the histology. Gastrointest Endosc 1999; 49: 493-7.  Back to cited text no. 17


  [Figure 1], [Figure 2], [Figure 3]

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