Concomitant Case of Intraductal Papillary Mucinous Neoplasm of the Pancreas and Functioning Pancreatic Neuroendocrine Tumor (Vasoactive Intestinal Polypeptide-Producing Tumor): First Report

Pancreatic Neuroendocrine Neoplasm Concomitant with Branch-duct Intraductal Papillary Mucinous Neoplasm: A Case Report and Literature Review

Reports of pancreatic neuroendocrine neoplasm (P-NEN) concomitant with intraductal papillary mucinous neoplasm (IPMN) are gradually increasing. However, many of these cases were diagnosed in the resected specimen incidentally. We herein report a case of minimal P-NEN concomitant with branch-duct IPMN that was successfully diagnosed preoperatively by contrast-enhanced endoscopic ultrasonography (EUS) and an EUS-guided fine-needle biopsy. These findings suggest that P-NEN as well as pancreatic ductal adenocarcinoma should be considered as concurrent tumors developing in patients with IPMNs. EUS is an essential modality when evaluating IPMN for detecting small lesions concomitant with IPMN.

Case report: composite pancreatic intraductal papillary mucinous neoplasm and neuroendocrine tumor: a new mixed neuroendocrine-non-neuroendocrine neoplasm?

BACKGROUND

Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) of the pancreas are extremely rare. Their pathogenesis and molecular landscape are largely unknown. Here, we report a case of mixed pancreatic intraductal papillary mucinous neoplasm (IPMN) and well-differentiated neuroendocrine tumor (NET) and identify its genetic alterations by next-generation sequencing (NGS).

CASE PRESENTATION

A fifty-year-old male was admitted into the hospital for evaluation of a pancreatic lesion detected during a routine examination. Abdominal ultrasound indicated a hypoechoic mass of 2.6 cm at the head of the pancreas. Malignancy was suspected and partial pancreatectomy was performed. Thorough histopathological examination revealed a mixed IPMN-NET. In some areas, the two components were relatively separated, whereas in other areas IPMN and NET grew in a composite pattern: The papillae were lined with epithelial cells of IPMN, and there were clusters of NET nests in the stroma of papillary axis. NGS revealed shared somatic mutations (KRAS, PCK1, MLL3) in both components. The patient has been uneventful 21 months after the surgery.

CONCLUSIONS

Our case provides evidence of a common origin for mixed IPMN-NET with composite growth features. Our result and literature review indicate that KRAS mutation might be a driver event underlying the occurrence of MiNEN. We also recommend the inclusion of mixed non-invasive exocrine neoplasms and neuroendocrine neoplasms into MiNEN.

Pancreatic Neuroendocrine Tumors and Intraductal Papillary Mucinous Neoplasm of the Pancreas: A Systematic Review

OBJECTIVES

This study aimed to identify factors that explain the association of intraductal papillary mucinous neoplasms-pancreatic neuroendocrine tumors (IPMNs-PNETs), radiological characteristics, and factors that might guide therapy.

METHODS

We performed a systematic review of the literature to search for articles on concurrent IPMN-PNET, mixed endocrine-exocrine pancreatic tumors, and/or PNET with an intraductal growth pattern.

RESULTS

A review of the literature suggests that there is some confusion about association of IPMNs-PNETs. Regarding this association, the studies collected data from 32 patients. Eleven patients presented concurrent tumors, 9 mixed endocrine-exocrine tumors, and no data were available in the remaining 7. In addition, the relationship IPMN-PNET focuses not only on the coexistence of the 2 lesions, but also on the possibility of the intraductal growth of the endocrine lesion. In the literature, in 4 cases, the preoperative radiological diagnosis had been IPMN.

CONCLUSIONS

Intraductal papillary mucinous neoplasms and PNETs may be associated in a number of scenarios. The association may be due to the concurrent existence of independent lesions, may be a mixed endocrine-exocrine tumor, or may be due to intraductal growth of the endocrine lesion. But the literature is confusing. It is not known whether the association is accidental or whether there is an etiological reason. Further studies are needed to investigate this scenario.

Intraductal papillary mucinous neoplasm of the pancreas associated with neuroendocrine tumor: A case report

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The panreatic IPMN and neuroendocrine carcinoma is very unusual.

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The IPMN component of our patient has high grade dysplasia, which is very rare.

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In presence of contrast enhancing nodular foci, while evaluating IPMN on imaging studies, possibilty of neuroendocrine tumor should be in mind.

Introduction

Intraductal papillary mucinous neoplasm is an uncommon cystic tumor of pancreas that can be associated with ductal adenocarcinoma. Coexistence of pancreatic IPMN and neuroendocrine tumor is very rare. Here, we report the imaging features of mixed type intraductal papillary mucinous neoplasia of the pancreas with high grade dysplasia together with neuroendocrine carcinoma and perform review of the literature.

Presentation

A 68-year old patient has been evaluated for possible IPMN that was suspected during ultrasound. MRI revealed main and side branch duct dilatations. At the head, a contrast enhancing nodular lesion was identified. Due to the presence of high risk stigmata according to guidelines, surgery was performed. Histopathological examination revealed an unusual association, including mixed type IPMN and neuroendocrine carcinoma.

Discussion

The concomitant occurrence of pancreatic IPMN and neuroendocrine tumor has been reported in case studies and brief reviews. Yet, the imaging findings and underlying molecular mechanisms of this entity has not been fully understood. In addition to this unusual association, pancreatic intraepithelial neoplasia was also detected in the present case. Although majority of neuroendocrine tumor associated IPMNs were reported to be having low grade dysplasia, our patient had high grade dysplasia. Further studies and reviews with larger groups are needed to establish imaging features and underlying molecular mechanisms of this rare association.

Conclusion

Although the major concern during work-up of IPMN is presence of associated pancreatic ductal adenocarcinoma, the possibility of neuroendocrine tumor, in the presence of a hypervascular solid foci on imaging studies should be kept in mind.

Synchronous intraductal papillary mucinous neoplasm and a pancreatic neuroendocrine tumor: more than a coincidence?

BACKGROUND

Although the association between intraductal papillary mucinous neoplasm of the pancreas (IPMN) and pancreatic neuroendocrine tumor (PNET) has been increasingly reported, whether this association is real or coincidence remains unclear. We report a case of synchronous IPMN and a PNET which were diagnosed preoperatively and discuss the tumorigenesis, clinicopathological features and management of these rare tumors based on the published literature.

CASE REPORT

A 56-year-old male was incidentally diagnosed with a 14 mm branch duct IPMN and a 3.6 mm non-functional PNET during an evaluation due to persistent upper abdominal pain via endoscopic ultrasound. Close follow-up of the patient was decided as the IPMN had no worrisome features. A review of twenty-two previously reported cases of synchronous IPMN and PNET indicated that: a) only seven cases were diagnosed preoperatively; b) abdominal pain was the main presenting symptom; c) IPMN was the dominant tumor and presented with low grade dysplasia; d) the PNET was small and non-functional and had an indolent behavior; and e) only one case underwent radiologic follow-up.

DISCUSSION

IPMN are associated with other pancreatic and extrapancreatic malignancies. Thus, the entire pancreatic parenchyma should be examined closely during the evaluation of an IPMN in order to exclude other pancreatic lesions, for example, a PNET.

Collision of ductal adenocarcinoma and neuroendocrine tumor of the pancreas: a case report and review of the literature

BACKGROUND

Simultaneous occurrence of exocrine and neuroendocrine tumors of the pancreas is very infrequent. We report a patient with an endocrine tumor in the pancreatic-duodenal area and extensive exocrine carcinoma involving the whole pancreas.

CASE PRESENTATION

A 69-year-old woman was hospitalized in May 2016 for epigastric pain and weight loss. Her past medical history revealed an undefined main pancreatic duct dilation that was subsequently confirmed at CT scan (23 mm) and endoscopic ultrasound. There was no evidence of pancreatic masses, but the cephalic portion of the main pancreatic duct presented hypoechoic nodules. A diagnosis of the main-duct intraductal papillary mucinous neoplasm was made, and the patient underwent total pancreatectomy. Pathological examination showed a collision tumor constituted by a ductal adenocarcinoma involving the whole pancreas and a neuroendocrine tumor located in the duodenal peripancreatic wall and the head of the pancreas. There was one peripancreatic lymph node metastasis from the ductal adenocarcinoma and eight node metastases from the neuroendocrine tumor. These findings suggested a diagnosis of collision of neuroendocrine and ductal adenocarcinomas of the pancreas. The postoperative course was uneventful.

CONCLUSIONS

The coexistence of pancreatic endocrine and exocrine tumors is very uncommon. When present, problems in differential diagnosis may arise between mixed exocrine-endocrine carcinoma or the collision of separate tumors.