Adenocarcinoma with intraductal papillary mucinous neoplasm arising in jejunal heterotopic pancreas

Intraductal Papillary Mucinous Neoplasm Arising from Heterotopic Pancreas in Stomach: A Case Report and Review of Literature

Heterotopic pancreas is generally an asymptomatic condition which is found incidentally at surgery, endoscopy, or autopsy. Intraductal papillary mucinous neoplasm (IPMN) arising from heterotopic pancreas is extremely rare. In this study, we report a patient with IPMN arising from heterotopic pancreas. A 28-year-old man presented to our department with epigastric pain for 20 days. Physical examination revealed no abnormal findings. Computed tomography (CT) revealed an intramural cystic-solid mass on the gastric wall. Endoscopic ultrasonography (EUS) revealed a hypoechoic, heterogeneous, and multilobulated lesion with septa. Cyst fluid analysis based on EUS guided fine needle aspiration (EUS-FNA) indicated that the concentration of carcinoembryonic antigen (CEA) was 492 ng/ml. The patient received Billroth I subtotal gastrectomy, and then a 4.6 cm mass from the lesser curvature of the stomach was removed. Finally, the patient was diagnosed as IPMN with low grade dysplasia in an ectopic pancreas based on histopathological analysis. This report described the clinical, radiologic, endoscopic and histologic features of IPMN arising from heterotopic pancreas in a 28-year-old man involving the stomach. All pathologists involved in the diagnosis and clinicians involved in the treatment should be aware of this kind of tumor pattern to improve the correct identification, diagnosis and management of patients.

Clinicopathological features of intraductal papillary mucinous neoplasm derived from ectopic pancreas: A systematic review

Background

Methods

Results

Conclusion

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The ectopic pancreas can be complicated with pancreatitis, pseudocyst formation, cyst formation, insulinoma, adenoma, and malignant transformation. Intraductal papillary mucinous neoplasm (IPMN) derived from the ectopic pancreas is rare and can undergo malignant transformation.

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It is challenging to diagnose IPMN derived from ectopic pancreas preoperatively using the existing imaging modalities. Moreover, the clinicopathological characteristics of these tumors have not been elucidated.

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We performed a review of case reports on IPMNs derived from the ectopic pancreas, including intraductal papillary mucinous carcinoma (IPMC) that was treated in our hospital, to determine the clinicopathological features of the tumors.

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This is the first systematic review of the literature on IPMN derived from the ectopic pancreas. The review revealed that IPMN derived from the ectopic pancreas was diagnosed incidentally in most patients, and some patients were asymptomatic.

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The existing imaging modalities may not accurately diagnose the condition preoperatively and differentiate between IPMN and IPMC. Risk factors for malignant transformation should be clarified through further research.

A case of ectopic pancreas of the stomach accompanied by intraductal papillary mucinous neoplasm with GNAS mutation

BACKGROUND

Ectopic pancreas is basically a benign disease and is not always necessary to be removed. However, all types of neoplasms occurring in the normal pancreas such as ductal adenocarcinomas and intraductal papillary mucinous neoplasms (IPMNs) may develop even within ectopic pancreas. We recently encountered an extremely rare case of ectopic pancreas in the gastric antrum associated with IPMN possessing a GNAS mutation.

CASE PRESENTATION

A 71-year-old Japanese woman complained of epigastric pain. Computed tomography and upper gastrointestinal endoscopy showed an intramural cystic mass in the antrum of the stomach. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) biopsy did not give a definitive diagnosis, and the patient underwent resection of the lesion. Histology of the resected specimen showed that the gastric intramural lesion was ectopic pancreas. Moreover, the lesion contained dilated duct components with tubulo-villous epithelial proliferation consistent with pancreatic IPMN. Since the covering epithelial cells had highly atypical nuclei, the lesion was diagnosed as IPMN with high grade dysplasia. Immunohistochemistry showed that the IPMN component showed to be MUC2-, MUC5AC-, and CDX2-positive but MUC1- and MUC6-negative. Mutational analyses using genomic DNA revealed that the IPMN component had a mutation of GNAS at exon 8 (Arg201Cys).

CONCLUSION

We finally diagnosed this case as gastric ectopic pancreas accompanied by intestinal type IPMN with high grade dysplasia possessing GNAS mutation. Although there were 17 cases of ectopic pancreas with IPMN including 6 cases of gastric ones reported in the English literature, this is the first case of ectopic pancreas with IPMN which was proved to have GNAS mutation. Intimate preoperative examinations including imaging analyses and EUS-FNA biopsy/cytology are recommended to decide whether the lesion has to be resected or not even if they are not effective for getting the right diagnosis.

Adenocarcinoma with intraductal papillary mucinous neoplasm arising in a duodenal heterotopic pancreas: a case report

A woman in her 70 s was diagnosed with a tumor in her duodenal wall during a routine visit for diabetes. She subsequently underwent subtotal stomach-preserving pancreatoduodenectomy. Histologically, the tumor was present mainly in the duodenal wall, and atypical cystic ducts were seen in the muscularis propria and subserosa. Invasive well-differentiated adenocarcinoma was seen in the duodenal submucosal and mucosal layers. Heterotopic pancreatic tissue was seen within the tumor, and atypical epithelium had proliferated and replaced the cystic ductal epithelium of the heterotopic pancreas. Therefore, adenocarcinoma with intraductal papillary mucinous neoplasm arising in duodenal heterotopic pancreas was the final histopathological diagnosis, which is considered rare.

Malignant Transformation of Ectopic Pancreas

Malignant transformation of ectopic pancreas tissue is a diagnostic challenge as clinical symptoms and radiographic features of these tumors are non-specific. Given the rarity of these lesions, it is usually neither suspected nor included in the diagnostic workup of different tumors. We conducted a comprehensive literature review regarding malignancy arising from ectopic pancreas for a better understanding of its frequency, clinicopathological features, and prognosis. A literature search was performed in three major databases: PubMed, Cochrane, and Web of Science. Fifty-four well-documented cases of malignant ectopic pancreas were identified in the published literature. Our analysis provided the following observations: (1) there was a slight predominance of males over females; (2) most patients with malignant transformation of ectopic pancreas were middle-aged; (3) most commonly, the tumor was located in the stomach; (4) most tumors were adenocarcinomas; (5) most frequently, the malignancy arose within a type I heterotopia according to Heinrich classification; (6) macroscopically, a subepithelial-like appearance was most frequently observed; and (7) improved prognosis for ectopic pancreatic malignancies in comparison with reported survival data for orthotopic pancreatic cancer. Even if the majority of cases of ectopic pancreas are incidental findings and malignant transformation is a rare event, pancreatic heterotopy should be considered as a source of potentially malignant lesions.

Intraductal papillary mucinous neoplasm originating from a heterotopic pancreas within the jejunum: a case report

We report a case of intraductal papillary mucinous neoplasm arising within the heterotopic pancreatic tissue which was found incidentally in the jejunum during surgery for bowel obstruction. A 54-year-old female patient was admitted to our hospital due to sudden abdominal pain. In preoperative findings, we diagnosed bowel obstruction and performed surgery. Intra-operative findings showed adhesive intestinal obstruction, we performed synechiotomy for adhesion release. During surgery, when searching the small intestine, we coincidentally found a tumor in the jejunum and partial resected the jejunum. Pathological examination revealed a 1.2 cm × 1.0 cm × 1.0 cm white yellow nodule with cystic spaces. Histological examination demonstrated heterotopic pancreatic tissue consisting of well-formed lobules of pancreatic acini and cystically dilated ducts containing intraductal papillary neoplasm. Moreover, in immunohistochemical staining, MUC5AC was diffusely expressed, but not MUC1, MUC2 and MUC6.

Heterotopic Pancreas of the Gastrointestinal Tract and Associated Precursor and Cancerous Lesions: Systematic Pathologic Studies of 165 Cases

Heterotopic pancreas (HP) can be detected by accompanying symptoms or incidentally during gastrointestinal (GI) tract tumor resection. We compared clinicopathologic features among 165 resected HPs (57 gastric [35%], 56 duodenal [34%], 30 omental [18%], and 22 jejunal [13%]). Symptomatic HPs (79/135 GI tract wall HPs, 59%) were larger (P=0.05), more common in younger patients and in a gastric location (both P<0.001), and more frequently associated with lymphoid cuffs (P=0.03) than incidentally found HPs. Gastric/jejunal HPs were more frequently symptomatic (P<0.001), deeply located (P=0.03), and associated with lymphoid cuffs (P=0.008) and pancreatic intraepithelial neoplasia/intraductal papillary mucinous neoplasms (PanIN/IPMN; P=0.001) than duodenal HPs. HP was frequently associated with acinar-ductal metaplasias (117/135 GI tract wall HPs, 87%) and PanINs/IPMNs (68/135, 50%); those with PanINs/IPMNs were larger (P<0.001), more frequently located in stomach (P=0.001), had deeper wall involvement (P=0.03), and more often showed infiltrative growth (P<0.001) and lymphoid cuffs (P=0.02). Four HPs containing PanINs abutted adenocarcinomas, all expressing wild-type KRAS and intact SMAD4/DPC4 expression. Thus, symptomatic HP is associated with younger age, larger size, gastric location, and lymphoid cuffs. HPs containing PanINs/IPMNs (usually low grade) are larger and more common in stomach, have deeper wall location, and show infiltrative growth and lymphoid cuffs. Adenocarcinomas are rarely observed adjacent to HPs with PanINs/IPMNs. KRAS mutational and SMAD4/DPC4 immunohistochemical studies can discriminate between adenocarcinoma derived from HP and concurrent adenocarcinoma with HP.

Adenocarcinoma arising from jejunal ectopic pancreas mimicking peritoneal metastasis from colon cancer: a case report and literature review

Adenocarcinoma arising from jejunal ectopic pancreas is very rare. We report a case of a 69-year-old female with adenocarcinoma arising from jejunal ectopic pancreas after resection of advanced colon cancer. She underwent right hemicolectomy for advanced ascending colon cancer (ypT3N0M0, stage IIA) after chemotherapy. Two and half years after colectomy, her tumor markers were elevated, and computed tomography revealed a mass measuring 20 × 20 mm in the small intestine, having an abnormal uptake of ¹⁸F-fluorodeoxyglucose on ¹⁸F-fluorodeoxyglucose-positron emission tomography (¹⁸FDG-PET). Double-balloon enteroscopy revealed a submucosal tumor in the jejunum, and histopathology of biopsy specimens from that lesion showed ectopic pancreas without malignancy. Therefore, peritoneal metastasis from colon cancer concomitant with ectopic pancreas or adenocarcinoma arising from ectopic pancreas was considered as a differential diagnosis. She underwent laparoscopic jejunectomy. Pathological examination revealed a moderately differentiated adenocarcinoma arising from jejunal ectopic pancreas, not peritoneal metastasis from colon cancer. Even if histopathology of the biopsy specimen shows ectopic pancreas without malignancy, adenocarcinoma arising from ectopic pancreas should be considered when the tumor markers are elevated or the lesion has an abnormal uptake of ¹⁸FDG.

Intraductal papillary mucinous neoplasm of the ileal heterotopic pancreas in a patient with hereditary non-polyposis colorectal cancer: A case report

We report a case of intraductal papillary mucinous neoplasm (IPMN) originating from the ileal heterotopic pancreas in a patient with hereditary non-polyposis colorectal cancer (HNPCC). A 49-year-old woman had a past history of total colectomy and total hysterectomy with bilateral salpingo-oophorectomy due to colonic adenocarcinoma and endometrial adenocarcinoma 11 years ago. Her parents died from colonic adenocarcinoma and her sister died from colonic adenocarcinoma and endometrial adenocarcinoma. The clinician found an ileal mass with necrotic change and the mass increased in size from 1.7 cm to 2.2 cm during the past 2 years on computed tomography. It was surgically resected. Microscopically, the ileal mass showed heterotopic pancreas with IPMN high grade dysplasia. Immunohistochemical staining revealed positive reactivity for MLH1/PMS2 and negative reactivity for MSH2/MSH6. This is the first report of IPMN originating from the ileal heterotopic pancreas in a patient with HNPCC in the English literature.

Heterotopic Pancreas within the Proximal Hepatic Duct, Containing Intraductal Papillary Mucinous Neoplasm

We report a unique first case of benign heterotopic pancreas arising within the proximal hepatic bile duct, containing a focus of intraductal papillary mucinous neoplasm (IPMN). The condition was diagnosed on pathological explant after left hepatic lobectomy with total extrahepatic bile duct excision.