Gene expression profiling of pancreatic neuroendocrine carcinoma and mixed neuroendocrine-non-neuroendocrine neoplasm

Pancreatic neuroendocrine carcinoma (NEC) and mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) are rare pancreatic malignant tumors, and comprehensive gene analyses are scarce. In this study, six NECs and six MiNENs were collected, immunohistochemistry for synaptophysin, chromogranin A, INSM1, Ki-67, and Rb was conducted, and KRAS mutational status was examined. Among these cases, comprehensive gene expression analysis of oncogene pathways using nCounter® were performed with six NECs and four MiNENs, and those data were compared with that of three pancreatic ductal adenocarcinomas (PDACs), with that of three normal pancreatic ducts, and with each other. By dividing NEC and MiNEN cases into KRAS-mutated group and KRAS-wild group, the difference of clinicopathological data and gene expression profiling data were examined between the two groups. Compared to the data of normal pancreatic epithelium, all 13 cancer-related pathways were upregulated in PDAC, MiNEN, and NEC group with more upregulation in this order. Compared to the data of PDAC, genes of DNA Damage repair pathway was most upregulated both in NECs and MiNENs. Regarding the difference between KRAS-mutated and KRAS-wild groups, several genes were differentially expressed between the two, where MMP7 was the upregulated gene with highest p-value and NKD1 was the downregulated gene with highest p-value in KRAS-mutated group. From the extent of upregulation of 13 pathways, MiNEN was considered more progressed stage than PDAC, and NEC was considered more progressed than MiNEN. From the comparison of KRAS-mutated and KRAS-wild NECs and MiNENs, several differentially expressed genes were identified in this study.

Gastric Amphicrine Carcinoma Showing Neuroendocrine and Pancreatic Acinar Cell Differentiation. Lesson from a Challenging Case Opening New Perspectives in the Diagnostic Work-Up of Gastric Neuroendocrine Neoplasms

Amphicrine carcinomas are epithelial neoplasms composed of cells with co-existing exocrine-neuroendocrine phenotype and are challenging lesions from both diagnostic and therapeutic perspectives.Here, we report the case of a 63-year-old male patient with a gastric nodule that was endoscopically biopsied, revealing histological features of a type 3 well-differentiated gastric neuroendocrine tumor (NET). At imaging, the lesion was single and limited to the stomach, but did not present In-111Octreotide uptake, despite SSTR2A immunohistochemical expression. The patient underwent a wedge resection of the gastric wall, with a final pathological diagnosis of amphicrine carcinoma with pancreatic acinar cell and neuroendocrine features (pT1b). Predictive immunohistochemistry showed microsatellite stability and negative HER2 status. Hotspot targeted deep sequencing of 57 genes showed no somatic mutation, in agreement with the low mutational burden reported for gastric amphicrine carcinomas. Due to a low stage of the tumor and the poor performance status of the patient, no additional oncological treatment was administered. The patient was disease-free after 18 months.This unusual case highlights the importance of considering amphicrine carcinoma in the diagnostic work-up of gastric type 3 NET. This can be done by including in the immunohistochemical panel non-neuroendocrine markers, such as the pancreatic acinar cell and glandular ones. Correct pathological diagnosis is pivotal to determine the appropriate staging (NET vs exocrine one) for surgical and oncological management.

Long-term survival of gastric mixed neuroendocrine-non-neuroendocrine neoplasm: Two case reports

BACKGROUND

Gastric mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN), which consists of neuroendocrine and non-neuroendocrine components, is quite rare. Until now, most data on gastric MiNEN come from clinical cases, without large-scale retrospective studies or controlled clinical trials. Consequently, no consensus regarding the origin, molecular characteristics, or appropriate treatment of MiNEN has been reached so far. We conducted chemotherapy of irinotecan plus cisplatin (IP regimen) and surgery in two patients with gastric MiNEN, which had never been used in treating this kind of tumor, leading to their long-term survival for more than 3 and 7 years, respectively.

CASE SUMMARY

We present two patients (one male and one female) with gastric MiNEN, with the primary manifestation of recurrent upper abdominal pain. After they were referred to our hospital, a diagnosis of gastric MiNEN was defined with the help of CT scan, and histopathological and immunohistochemical examinations on the samples of gastrointestinal endoscopy or radical surgery. The male patient (case 1) were found to have metastases in the reginal lymph nodes and the left liver. He received four cycles of IP regimens first, then the gastrectomy and partial left liver resection, followed by additional two cycles of IP chemotherapy. The female patient (case 2) underwent a laparoscopic gastrectomy, and received six cycles of IP regimen. She was found to have metastatic lesions in the right lung 2 years after that, and underwent video-assisted thoracoscopic surgery (VATS) of the lower lobe of the right lung. The two patients have now survived for more than 3 years and 7 years, respectively, without any evidence of recurrence or metastases.

CONCLUSION

IP regimen, combined with curative-intent surgery if feasible, could be considered as the priority in the choice of front-line chemotherapy for gastric MiNEN.

Surgical resection of mixed neuroendocrine-non-neuroendocrine neoplasm in the biliary system: a report of two cases

BACKGROUND

Mixed neuroendocrine-non-neuroendocrine neoplasm (MINEN) is a rare disease and there is scarce literature on its diagnosis, treatment, and prognosis. We encountered two unusual cases of MINEN in the biliary tract, one in the ampulla of Vater and the other in the distal bile duct. In this report, we describe the clinical course of these two cases in detail.

CASE PRESENTATION

Case 1: A 69-year-old woman presented with a chief complaint of epigastric pain. When endoscopic sphincterotomy and retrograde biliary drainage were performed for gallstone pancreatitis, an ulcerated lesion was found in the ampulla of the Vater. Based on the biopsy results, the lesion was diagnosed as the ampulla of Vater carcinoma and subtotal stomach-preserving pancreatoduodenectomy (SSPPD) was performed. Postoperative histopathological examination revealed the coexistence of adenocarcinoma and neuroendocrine carcinoma components, consistent with the diagnosis of MINEN. In addition, lymph node metastasis was found on the dorsal side of the pancreas and the metastatic component was adenocarcinoma. Adjuvant chemotherapy with etoposide and cisplatin was administered for 6 months, and presently the patient is alive without recurrence 64 months after surgery. Case 2: A 79-year-old man presented with a chief complaint of anorexia. Cholangiography showed severe stenosis of the distal bile duct. A biopsy was conducted from the stenotic lesion and it revealed the lesion to be adenocarcinoma. A diagnosis of distal bile duct carcinoma was made, and SSPPD was performed. Histopathological examination revealed the coexistence of adenocarcinoma and neuroendocrine carcinoma components, and the tumor was confirmed as MINEN of the distal bile duct. No adjuvant chemotherapy was administered due to the poor performance status. 7 months later, the patient was found to have a liver metastasis.

CONCLUSION

We experienced two valuable cases of biliary MINEN. To identify better treatments, it is important to consider the diversity of individual cases and to continue sharing a variety of cases with different presentations.

Composite intestinal adenoma-microcarcinoid: An update and literature review

Composite intestinal adenoma-microcarcinoid (CIAM) is a rare intestinal lesion consisting of conventional adenoma and small, well differentiated carcinoid [microcarcinoid (MC)] at its base. The incidence of CIAM is 3.8% in surgically resected colorectal polyps. While its pathogenesis is unknown, studies support the role of Wnt/β-catenin pathway in the tumorigenesis of CIAM. CIAMs have been primarily reported in the colon wherein they present as polyps with well-defined margins, similar to conventional adenomatous polyps. MC is usually found in adenomatous polyps with high-risk features such as large size, villous architecture, or high grade dysplasia. Histologically, the MC component is often multifocal and spans 3.9 to 5.8 millimeters in size. MC is usually confined within the mucosa but occasional CIAM cases with MC extending to the submucosa have been reported. MC of CIAM demonstrates bland cytology and inconspicuous proliferative activity. The lesional cells are positive for synaptophysin and 60% to 100% of cases show nuclear β-catenin positivity. MC poses a diagnostic challenge with its morphologic and immunohistochemical resemblance to both benign and malignant lesions, including squamous morules/metaplasia, adenocarcinoma, squamous cell carcinoma, sporadic neuroendocrine tumor and goblet cell adenocarcinoma. CIAM is an indolent lesion with a favorable outcome. Complete removal by polypectomy is considered curative. Awareness and recognition of this rare entity will help arrive at correct diagnosis and improve patient care. Currently, CIAM is not recognized as a subtype of mixed neuroendocrine-non-neuroendocrine neoplasm by WHO.

Mixed neuroendocrine-non-neuroendocrine tumour of pancreas mimicking groove pancreatitis: Case report

Introduction

Mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) is a rare tumour of the pancreas which can mimic groove pancreatitis.

Case report

We present a 49-year-old Indian male presented with constant, dull-aching epigastric pain for last 6 months radiating to back, not associated with jaundice, gastrointestinal bleed, fever or weight loss. He also had history of alcohol abuse for last 15 years. Physical examination was unremarkable. Laboratory investigations were within normal limits. Contrast enhanced computed tomography (CT) of the abdomen was suggestive of groove pancreatitis. CA 19.9, CEA and IgG4 levels were normal. Upper gastrointestinal endoscopy revealed an oedematous mucosa with narrowing of second part of duodenum. Endoscopic ultrasound (EUS) showed bulky pancreas with ill-defined heteroechoic head with periduodenal soft tissue thickening. EUS guided fine needle aspiration revealed chronic inflammatory cells. Based on the endoscopic findings and imaging, we suspected the diagnosis to be groove pancreatitis. He underwent open Whipple's pancreaticoduodenectomy. Histopathological evaluation revealed well differentiated neuroendocrine tumour and immunohistochemistry revealed features which was consistent with mixed neuroendocrine-non-neuroendocrine tumour (MiNEN). Post-operative period was uneventful and he was discharged on post-op day 7. A PET-CT scan was done to look for any silent metastasis and it was negative. He recieved 4 cycles of cisplatin-based chemotherapy. He was symptom free and doing well on 12 months follow up with no evidence of recurrence in surveillance CT imaging.

Discussion

Pancreatic MiNEN is characterised by presence of two malignant tissues, adenocarcinoma and NET, with one constituent involving at least 30% of the tumour. We report the pitfalls in diagnostic work-up which can lead to misdiagnosis of this rare entity. Specially due to admixture of different kinds of tissue, radiological investigations can be misleading.

Conclusion

Our case highlights the fact that MiNEN of pancreas can mimic a benign condition like groove pancreatitis. If routine histopathological and immunohistochemical evaluation is not done on the resected samples, relying on radiological and fine-needle aspiration cytology evidences, the actual diagnosis could be missed.

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MiNEN of pancreas is a rare pathology and difficult to diagnose preoperatively.

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MiNENs should be considered as a differential for groove pancreatitis.

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Histopathology with immunohistochemistry should be done for all pancreatoduodenectomy specimen to diagnose such rare tumors.

Recurrent Mixed Neuroendocrine-Non-Neuroendocrine Neoplasm in the Gallbladder: A Case Report

Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) of the gallbladder are rare with no established therapeutic strategies. We report a case of recurrent gallbladder MiNEN from a population with a low incidence of gallbladder carcinomas, a review of the current therapeutic options, and recent updates on the nomenclature proposed by the World Health Organization in 2017.

Gallbladder Mixed Neuroendocrine-Non-neuroendocrine Neoplasm (MiNEN) Arising in Intracholecystic Papillary Neoplasm: Clinicopathologic and Molecular Analysis of a Case and Review of the Literature

Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) of the gallbladder are generally composed of adenocarcinoma and neuroendocrine carcinoma (NEC). Rare cases associated with intracholecystic papillary neoplasm (ICPN) have been reported. Although recent molecular data suggest that the different components of digestive MiNENs originate from a common precursor stem cell, this aspect has been poorly investigated in gallbladder MiNENs. We describe the clinicopathologic and molecular features of a MiNEN composed of ICPN, adenocarcinoma, and NEC. A 66-year-old woman presented with severe abdominal pain. She underwent radical cholecystectomy and an intracholecystic mass was found. Histologically, it was composed of ICPN associated with adenocarcinoma and large cell neuroendocrine carcinoma (LCNEC). The three components were positive for DNA repair proteins and p53. EMA was positive in the ICPN and adenocarcinoma components, while it was negative in the LCNEC. Heterogeneous expression of Muc5AC, cytokeratin 20, and CDX2 was only observed in the ICPN component. Cytokeratin 7 was diffusely positive in both adenocarcinoma and LCNEC components, while it was heterogeneously expressed in the ICPN. The copy number variation analysis showed overlapping results between the adenocarcinoma and LCNEC components with some minor differences with the ICPN component. The three tumor components showed the same mutation profile including TP53 mutation c.700T > C (p. Tyr234His), without mutations in other 51 genes known to be frequently altered in cancer pathogenesis and growth. This finding may support the hypothesis of a monoclonal origin of the different tumor components. We have also performed a review of the literature on gallbladder MiNENs.