Ectopic pancreas with lipoma in the distal jejunum: A case report

Open AccessPublished:December 28, 2020DOI:https://doi.org/10.1016/j.ejro.2020.100318

      Abstract

      Ectopic pancreas is asymptomatic and mostly found in the stomach and proximal small bowel. It is difficult to distinguish ectopic pancreas with other submucosal tumors of the gastrointestinal (GI) tract on computed tomography (CT) without histological confirmation. The author encountered a case of ectopic pancreas coexisting with submucosal lipoma in the distal jejunum which was misdiagnosed as fat-containing submucosal tumor. The author reports the CT findings and reviews previously reported cases of ectopic pancreas coexisting with submucosal lipoma. The knowledge that ectopic pancreas can occur with benign lipoma, and its imaging features would be helpful for the diagnosis and management of patients.

      Keywords

      1. Introduction

      Ectopic pancreas is the presence of histologically-confirmed pancreatic tissue outside the anatomic boundaries of the pancreas and lacks both anatomical and vascular connections [
      • Bromberg S.H.
      • CamiloNeto C.
      • Borges A.F.A.
      • Franco M.I.F.
      • França L.C.M.
      • Yamaguchi N.
      Pancreatic heterotopias: clinicopathological analysis of 18 patients.
      ]. Cases of ectopic pancreas have been identified throughout the entire length of the gastrointestinal (GI) tract, but the majority of the cases occur in the stomach and the proximal small bowel [
      • Fikatas P.
      • Sauer I.M.
      • Mogl M.
      • Menenakos C.
      • Luegering A.
      • Schumacher G.
      • et al.
      Heterotopic ileal pancreas with lipoma and coexisting fibromatosis associated with a rare case of gastrointestinal bleeding. A case report and review of the literature.
      ]. Computed tomography (CT) findings of ectopic pancreas is nonspecific; therefore, diagnosis before pathological-confirmation is difficult. Moreover, the differential diagnosis of ectopic pancreas occurring in the GI tract and coexisting with other tumors might be challenging. There are a few reported cases of ectopic pancreas coexisting with other tumors, which were mostly malignant or premalignant lesions [
      • Tu C.Y.
      • Zhu W.L.
      • Shao C.X.
      • Zhu J.D.
      • Tu J.F.
      • Zhou X.M.
      • et al.
      Diagnosis and treatment of heterotopic pancreas coexisting with digestive tract tumor: a report of 26 cases.
      ]. On the contrary, the present case of ectopic pancreas coexisted with benign lipoma, which was misdiagnosed as a fat containing submucosal tumor on CT scan. Herein, the author reports a case of ectopic pancreas with lipoma in the distal jejunum.

      2. Case presentation

      A 38-year-old man visited our institution for evaluation of melena, intermittent epigastric and left upper quadrant pain lasting for one week. He had no medication history of non-steroidal anti-inflammatory drugs (NSAIDs) or aspirin. On physical examination, he had abdominal tenderness in epigastric area and the bowel sounds were normal. Digital rectal examination showed remnants of melena without other pathological findings. He got the Levin-tube irrigation of stomach and clear fluid was presented. At the time of admission, his systolic/diastolic blood pressure was 95/45 mmHg. Laboratory examination revealed the hemoglobin level of 6.1 g/dL and the hematocrit level of 18.3 %. A contrast-enhanced computed tomography (CT) scan of the abdomen and pelvis revealed a 3.2 cm sized lobulated contour soft tissue mass in the distal jejunum. The mass was intraluminally protruded and overlying mucosa was intact. At the proximal portion, the mass was connected with homogeneous fat density portion (Fig. 1A). The possibility of submucosal tumor containing fat component, such as liposarcoma or submucosal tumor coexisting with lipoma was suggested. There was no evidence of small bowel obstruction nor ischemic change. During surgery, small bowel mass with intussusception was found, and laparoscopic assisted segmental resection of small intestine and anastomosis was performed. On the gross examination, the specimen showed an elongated polypoid mass (“finger-like” appearance) in a segment of the distal jejunum. The mass was measured as 8.0 cm × 2.0 cm × 1.5 cm. The adjacent mucosa was grossly normal (Fig. 1B). Microscopically, the polypoid lesion was covered by the mucosa. In the submucosa, groups of pancreatic tissue (pancreatic acini, islets of Langerhans, and pancreatic ducts) were present. The pancreatic tissue was closely associated with a different tumor composed of mature fibro-adipose tissue (Fig. 1C). It suggests ectopic pancreas with co-occurred lipoma. After surgery, the patient was discharged in a few days without complications.
      Fig. 1
      Fig. 1A 38-year-old male with ectopic pancreas with lipoma in the distal jejunum.
      A. Serial axial precontrast (the upper row) and contrast-enhanced (the lower row) CT images reveal ectopic pancreas coexisting with lipoma in the distal jejunum. A 3.2 cm sized lobulated contoured enhancing soft tissue mass (arrows) in the distal jejunum. It is intraluminally protruded and overlying mucosa is intact. At the proximal segment of the lesion, the enhancing soft tissue mass is connected with homogeneous fat density portion (arrowheads).
      B. Gross specimen shows the elongated polypoid mass (“finger-like” appearance) in a segment of the distal jejunum measuring 8.0 cm × 2.0 cm × 1.5 cm.
      C. Microscopic specimens of the mass in the distal jejunum (H&E stain, ×40).
      The upper panel shows pancreatic tissue with acini (arrows) and ducts (arrowhead).
      The lower panel shows lipoma tissue composed of mature fibro-adipose tissue at the boundary of pancreatic tissue. The arrows indicate islets of Langerhans.

      3. Discussion

      Ectopic pancreas is a congenital anomaly in which the pancreatic tissue separates from the main gland and exists without vascular or ductal continuity [
      • Bromberg S.H.
      • CamiloNeto C.
      • Borges A.F.A.
      • Franco M.I.F.
      • França L.C.M.
      • Yamaguchi N.
      Pancreatic heterotopias: clinicopathological analysis of 18 patients.
      ]. Lipomas are benign tumors composed of mature fat tissue [
      • Thompson W.M.
      Imaging and findings of lipomas of the gastrointestinal tract.
      ]. Radiological findings of ectopic pancreas are similar to those of normal pancreas, and often present as ectopic nodular foci [
      • Cho J.S.
      • Shin K.S.
      • Kwon S.T.
      • Kim J.W.
      • Song C.J.
      • Noh S.M.
      • et al.
      Heterotopic pancreas in the stomach: CT findings.
      ]. However, ectopic pancreas demonstrates nonspecific CT density and enhancement pattern, similar to other submucosal tumors [
      • Buckley J.A.
      • Fishman E.K.
      CT Evaluation of small bowel neoplasms: spectrum of disease.
      ]. On the contrary, gastrointestinal lipoma may appear as an intraluminal mass with gross appearance similar to that of subcutaneous fat on CT [
      • Thompson W.M.
      Imaging and findings of lipomas of the gastrointestinal tract.
      ].
      In this case, the mass showed both submucosal enhancing soft tissue and fat component. Therefore, the differential diagnosis was difficult with the possibility of fat-containing submucosal tumor, such as submucosal tumor coexisting with lipoma and liposarcoma. Meanwhile, all the prior cases and present case of ectopic pancreas associated with lipoma were diagnosed following complications, likely related to the presence of lipoma itself rather than ectopic pancreas [
      • Fikatas P.
      • Sauer I.M.
      • Mogl M.
      • Menenakos C.
      • Luegering A.
      • Schumacher G.
      • et al.
      Heterotopic ileal pancreas with lipoma and coexisting fibromatosis associated with a rare case of gastrointestinal bleeding. A case report and review of the literature.
      ,
      • Jiang K.
      • Stephen F.O.
      • Jeong D.
      • Pimiento J.M.
      Pancreatic and gastric heterotopia with associated submucosal lipoma presenting as a 7-cm obstructive tumor of the ileum: resection with double balloon enteroscopy.
      ,
      • Sunitha N.
      • Flynn A.
      • Sathyakrishna B.R.
      • Anuradha A.D.
      • Harrison A.
      Pancreatic heterotopia in an ileal lipoma—a pathological rarity causing intestinal obstruction.
      ,
      • Papageorge M.
      • Waghray A.
      • Chen L.
      • Yoo J.
      Pedunculated small bowel lipoma with heterotopic pancreas causing intussusception.
      ,
      • Musthafa S.M.
      • Selvapathy M.B.
      • Kamalraj M.
      • Nivas
      • Ramesh A.
      Heterotopic pancreas: an unusual cause of intussusception.
      ,
      • Chuang M.T.
      • Tsai K.B.
      • Ma C.J.
      • Hsieh T.J.
      Ileoileal intussusception due to ileal ectopic pancreas with abundant fat tissue mimicking lipoma.
      ]. Therefore, in relation to the clinical relevance, simple lipoma may be the following preoperative radiological differential diagnosis. Next to the simple lipoma, the differential diagnoses of ectopic pancreas with submucosal lipoma include several types of tumors. Liposarcomas have various CT patterns based on the amount and distribution of fat in the tumor, and often present as fatty masses with enhanced soft-tissue density [
      • Kransdorf M.J.
      • Bancroft L.W.
      • Peterson J.J.
      • Murphey M.D.
      • Foster W.C.
      • Temple H.T.
      Imaging of fatty tumors: distinction of lipoma and well-differentiated liposarcoma.
      ]. Gastrointestinal stromal tumor (GIST) can present as an enhanced intraluminal mass or extend through the serosa as an exophytic mass. Leiomyoma is typically a round, well-circumscribed mass with soft-tissue density with homogeneous enhancement and frequent ulceration and bleeding, as in the present case [
      • Buckley J.A.
      • Fishman E.K.
      CT Evaluation of small bowel neoplasms: spectrum of disease.
      ]. Neuroendocrine tumors can appear as polypoid, plaque-like, or hyperenhancing mass and up to 70 % of the cases show calcification. Moreover, presence of metastases and multiple primary tumors in other organs and findings of stranding on CT because of fibrosis and desmoplastic reaction are common in case of mesenteric metastases [
      • Buckley J.A.
      • Fishman E.K.
      CT Evaluation of small bowel neoplasms: spectrum of disease.
      ].
      Retrospective examination of the CT findings of the present case showed that the lipomatous region of the mass was clearly distinct from the ectopic pancreas and grossly appeared as fat, which corresponded to the imaging findings of lipoma in the GI tract. The observations suggest the possibility of two different origins for the tumor coexisting in the same location.
      Each of these two conditions is well-known but rarely reported together in the same location in the GI tract. Previously reported cases of ectopic pancreas coexisting with tumors were malignant or premalignant lesions. For example, Tu et al. reported 26 cases of heterotopic pancreas coexisting with digestive tract tumors; 23 cases of adenocarcinoma (20 cases in the stomach and 3 cases in the colon), 2 cases of gastrointestinal stromal tumor (1 case each in the stomach and the proximal jejunum) and duodenal hemangioma [
      • Tu C.Y.
      • Zhu W.L.
      • Shao C.X.
      • Zhu J.D.
      • Tu J.F.
      • Zhou X.M.
      • et al.
      Diagnosis and treatment of heterotopic pancreas coexisting with digestive tract tumor: a report of 26 cases.
      ].
      On the contrary, only 6 cases of ectopic pancreas coexisting with benign lipoma have been reported (Table 1). Although ectopic pancreas has been reported to occur throughout the entire length of the GI tract, the majority of the cases occur in the stomach and proximal small bowel. Lipoma can occur anywhere along the gastrointestinal tract as well. The most common site for bowel lipoma is the colon (65–75 %), followed by the small bowel (20–25 %) and the stomach (5 %) [
      • Thompson W.M.
      Imaging and findings of lipomas of the gastrointestinal tract.
      ]. Ectopic pancreas with submucosal lipoma in previously reported cases were mostly located in the ileum (6 cases), and in the distal jejunum in the present case, and may have a tendency to occur in the distal small bowel. Contrary to the fact that most patients with ectopic pancreas are asymptomatic, all reported patients with ectopic pancreas coexisting with submucosal lipoma had symptoms and complications, such as GI bleeding, intussusception, or bowel obstruction, including in this case [
      • Fikatas P.
      • Sauer I.M.
      • Mogl M.
      • Menenakos C.
      • Luegering A.
      • Schumacher G.
      • et al.
      Heterotopic ileal pancreas with lipoma and coexisting fibromatosis associated with a rare case of gastrointestinal bleeding. A case report and review of the literature.
      ,
      • Jiang K.
      • Stephen F.O.
      • Jeong D.
      • Pimiento J.M.
      Pancreatic and gastric heterotopia with associated submucosal lipoma presenting as a 7-cm obstructive tumor of the ileum: resection with double balloon enteroscopy.
      ,
      • Sunitha N.
      • Flynn A.
      • Sathyakrishna B.R.
      • Anuradha A.D.
      • Harrison A.
      Pancreatic heterotopia in an ileal lipoma—a pathological rarity causing intestinal obstruction.
      ,
      • Papageorge M.
      • Waghray A.
      • Chen L.
      • Yoo J.
      Pedunculated small bowel lipoma with heterotopic pancreas causing intussusception.
      ,
      • Musthafa S.M.
      • Selvapathy M.B.
      • Kamalraj M.
      • Nivas
      • Ramesh A.
      Heterotopic pancreas: an unusual cause of intussusception.
      ,
      • Chuang M.T.
      • Tsai K.B.
      • Ma C.J.
      • Hsieh T.J.
      Ileoileal intussusception due to ileal ectopic pancreas with abundant fat tissue mimicking lipoma.
      ]. It is likely to be caused by the presence of lipoma rather than ectopic pancreas. Therefore, it is important to suggest the differential diagnosis of simple lipoma, especially for possible cases in relation with lipoma and encountered incidentally on abdominal examination performed due to other indications, to prevent complications.
      Table 1Previously reported cases and present case of ectopic pancreas with lipoma.
      No.AuthorsReported yearSex/AgeLocationClinical presentation
      1Fikatas et al. [
      • Fikatas P.
      • Sauer I.M.
      • Mogl M.
      • Menenakos C.
      • Luegering A.
      • Schumacher G.
      • et al.
      Heterotopic ileal pancreas with lipoma and coexisting fibromatosis associated with a rare case of gastrointestinal bleeding. A case report and review of the literature.
      ]
      2008M/28Distal ileumGI bleeding
      2Chuang et al. [
      • Chuang M.T.
      • Tsai K.B.
      • Ma C.J.
      • Hsieh T.J.
      Ileoileal intussusception due to ileal ectopic pancreas with abundant fat tissue mimicking lipoma.
      ]
      2010F/26Distal ileumlleoileal intussusception, Bowel obstruction
      3Jiang et al. [
      • Jiang K.
      • Stephen F.O.
      • Jeong D.
      • Pimiento J.M.
      Pancreatic and gastric heterotopia with associated submucosal lipoma presenting as a 7-cm obstructive tumor of the ileum: resection with double balloon enteroscopy.
      ]
      2015F/38Distal ileumGI bleeding, lleoileal intussusception, Bowel obstruction
      4Musthafa et al. [
      • Musthafa S.M.
      • Selvapathy M.B.
      • Kamalraj M.
      • Nivas
      • Ramesh A.
      Heterotopic pancreas: an unusual cause of intussusception.
      ]
      2015M/32Mid ileumGI bleeding, lleoileal intussusception, Bowel obstruction
      5Sunitha et al. [
      • Sunitha N.
      • Flynn A.
      • Sathyakrishna B.R.
      • Anuradha A.D.
      • Harrison A.
      Pancreatic heterotopia in an ileal lipoma—a pathological rarity causing intestinal obstruction.
      ]
      2017M/35Ileumlleoileal intussusception, Bowel obstruction
      6Papageorge et al. [
      • Papageorge M.
      • Waghray A.
      • Chen L.
      • Yoo J.
      Pedunculated small bowel lipoma with heterotopic pancreas causing intussusception.
      ]
      2018M/36Terminal ileumIleoileal intussusception, Bowel obstruction
      7Present case2019M/38Distal jejunumGI bleeding
      The precise etiology of each ectopic pancreas and lipoma remains unclear. Ectopic pancreas is considered to be caused by abnormal implantation of fragments of the ventral or dorsal pancreatic anlage in the intestinal wall during embryological development. Other theories, such as pancreatic metaplasia of endodermal tissue, have been proposed to explain ectopic pancreas in distant organs [
      • Gore R.M.
      • Levine M.S.
      ]. Lipomas are benign with limited information on their pathogenesis. An increased incidence of lipoma is noted with obesity, diabetes mellitus, high serum cholesterol, trauma, irradiation and familial history [
      • Goldblum J.
      • Weiss S.
      • Folpe A.L.
      Benign lipomatous tumors.
      ]. However, no predisposing factor was identified for the present patient.
      Limited options are available for the confirmative diagnosis and treatment of the small bowel lesions. Given the location of the lesion and presence of possible complications, such as gastrointestinal bleeding, obstruction, or intussusception, conventional or laparoscopic resection with anastomosis is considered an appropriate treatment till date for ectopic pancreas and lipoma in distal small intestine with good prognosis [
      • Gore R.M.
      • Levine M.S.
      ].
      Despite the difficulty associated with preoperative radiological diagnosis of ectopic pancreas with coexisting lipoma, knowledge of the fact that ectopic pancreas can occur with benign lipoma and its imaging features would be helpful for the diagnosis and management of patients.

      4. Conclusion

      Ectopic pancreas coexisting with lipoma is a rare presentation and can be misdiagnosed with other submucosal tumors of the GI tract on CT scan. Knowledge of the co-occurrence of ectopic pancreas with benign lipoma and its imaging features will help radiologists and clinicians to make appropriate therapeutic and management decisions before opting for invasive procedures.

      Ethical statement

      There is no ethical problem in this article to be declared.

      Funding statement

      The author has no disclosure of financial interest to report.

      Declaration of Competing Interest

      The author reports no declarations of interest.

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