Prognostic predictors for recurrence following curative resection in grade I/II pancreatic neuroendocrine tumours.

INTRODUCTION: Pancreatic neuroendocrine tumours (pNETs) have an excellent long-term survival after resection, but are associated with a high recurrence rate. Identification of prognostic factors affecting recurrences would enable identifying subgroup of patients at higher risk of recurrences, who may benefit from more aggressive treatment. METHODS: A retrospective analysis of prospectively maintained database of patients undergoing pancreatectomy with curative intent for grade I and II pNETs between July 2007 and June 2021 was performed. Perioperative and long-term outcomes were analysed. RESULTS: A total of 68 resected patients of pNETs were included in this analysis. Fifty-two patients (76.47%) underwent pancreaticoduodenectomy, 10 (14.7%) patients had distal pancreatectomy, and 2 (2.9%) patients underwent median pancreatectomy, while enucleation was performed in 4 patients (5.8%). The overall major morbidity (Clavien-Dindo III/IV) and mortality rates were 33.82% and 2.94%, respectively. At a median follow-up period of 48 months, 22 (32.35%) patients had disease recurrence. The 5-year overall survival and 5-year recurrence-free survival (RFS) rates were 90.2% and 60.8%, respectively. While OS was unaffected by different prognostic factors, multivariate analysis showed that lymph node involvement, Ki-67 index ≥5%, and presence of perineural invasion (PNI) were independently associated with recurrence. CONCLUSIONS: While surgical resection gives excellent overall survival in grade I/II pNETs, lymph node positivity, higher Ki-67 index, and PNI are associated with a high risk for recurrence. Patients with these characteristics should be stratified as high risk and evaluated for more intensive follow-up and aggressive treatment strategies in future prospective studies.

The Role of Laparoscopic Surgery in Localized Pancreatic Neuroendocrine Tumours.

OPINION STATEMENT: Pancreatic neuroendocrine tumours (PNETs) are a rare and heterogeneous group of tumours with various clinical manifestations and biological behaviours. They represent approximately 2-4% of all pancreatic tumours, with an incidence of 2-3 cases per million people. PNETs are classified clinically as non-functional or functional, and pancreatic resection is recommended for lesions greater than 2 cm. The surgical approach can involve "typical" and "atypical" resections depending on the number, size and location of the tumour. Typical resections include pancreaticoduodenectomy, distal pancreatectomy enucleation and, rarely, total pancreatectomy. Atypical resections comprise central pancreatectomies or enucleations. Minimally invasive pancreatic resection has been proven to be technically feasible and safe in high-volume and specialized centres with highly skilled laparoscopic surgeons, with consolidated benefits for patients in the postoperative course. However, open and minimally invasive pancreatic surgery remains to have a high rate of complications; there is no specific technical contraindication to minimally invasive pancreatic surgery, but an appropriate patient selection is crucial to obtain satisfactory clinical and oncological outcomes.

C19MC amplification and expression of Lin28A and Olig2 in the classification of embryonal tumors of the central nervous system: A 14-year retrospective study from a tertiary care center.

INTRODUCTION: CNS embryonal tumors (CET) other than medulloblastomas (MB) and atypical teratoid/rhabdoid tumors (AT/RTs), previously designated as 'central nervous system primitive neuroectodermal tumors' ('CNS PNETs'), are a heterogenous subset of tumors with poorly defined diagnostic criteria. Other than the subset of embryonal tumor with multilayered rosettes (ETMR) defined by C19MC amplification, most CETs are diagnosed by exclusion of other molecularly defined entities and histological mimics including MB, AT/RTs, and high-grade gliomas, and termed as CET, not otherwise specified (NOS) in the 2016 WHO classification. AIM: To reclassify 'CNS PNETs' as per WHO 2016, and estimate the true proportion of CET, NOS in a tertiary healthcare setting, and to evaluate the diagnostic utility of C19MC amplification, Lin28A and Olig2 expression in the subclassification of CETs. METHODS: Previously diagnosed cases of 'CNS PNETs' (2002-2016) were first evaluated by immunohistochemistry (IHC) for MIC2, RelaA, L1CAM, IDH1R132H, H3K27M, H3G34R, H3G34V, INI1, and BRG1 proteins and by fluorescence in-situ hybridization (FISH) for EWSR1 translocation to exclude histological mimics. The selected CETs (case cohort) and 79 histological mimics (comparison cohort) comprising of MB, AT/RT, pineal parenchymal tumors, Ewing sarcoma, esthesioneuroblastoma, intraocular medulloepithelioma, and H3G34R mutant high-grade glioma were subject to IHC for Olig2 and Lin28A, and FISH for C19MC amplification. RESULTS: Twenty-two cases of 'CNS PNETs' were retrieved, all of which were negative for the first panel of markers and showed retained INI-1/BRG1 expression. Three of them (3/22, 13.6%) showed C19MC amplification (ETMR, C19MC-altered) with ETMR histology, Lin28A positivity, and Olig2 negativity. Among the remaining 19 CETs, one showed medulloepithelioma histology (Medulloepithelioma, NOS) and remaining were non-descript small round cell tumors (CET, NOS), all negative for Lin28A. Olig2 was positive in only 3 CETs (13.6%), all being CET, NOS. All tumors in the comparison cohort were negative for C19MC amplification, Lin28A and Olig2 except for 27% of ATRTs that were Lin28A positive. CONCLUSION: ETMR, C19MC-altered constitute less than 14% of CETs, with majority remaining uncharacterized as CET, NOS. Lin28A is 100% sensitive for the detection of C19MC amplification; however, its specificity is limited by its expression in ATRTs. Olig2 expression is seen only in a small subset of CET, NOS and is of limited diagnostic utility.

Prognosis analysis of patients with pancreatic neuroendocrine tumors after surgical resection and the application of enucleation.

OBJECTIVE: To investigate the prognostic factors of patients with pancreatic neuroendocrine tumor (pNETs) after surgical resection, and to analyze the value of enucleation for pNETs without distant metastasis that are well-differentiated (G1) and have a diameter ≤ 4 cm. METHODS: Data from pNET patients undergoing surgical resection between 2004 and 2017 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier analysis and log-rank testing were used for the survival comparisons. Adjusted HRs with 95% CIs were calculated using univariate and multivariate Cox regression models to estimate the prognostic factors. P < 0.05 was regarded as statistically significant. RESULTS: This study found that female, cases diagnosed after 2010, and pancreatic body/tail tumors were protective factors for good survival, while histological grade G3, a larger tumor size, distant metastasis, AJCC 8th stage III-IV and age over 60 were independent prognostic factors for a worse OS/CSS. For the pNETs that were well-differentiated (G1) and had a tumor diameter ≤ 4 cm, the type of surgery was an independent factor for the long-term prognosis of this group. Compared with pancreaticoduodenectomy and total pancreatectomy, patients who were accepted enucleation had better OS/CSS. CONCLUSION: For pNETs patients undergoing surgical resection, sex, year of diagnosis, tumor location, pathological grade, tumor size, distant metastasis, race, and age were independent prognostic factors associated with the OS/CSS of patients. For pNETs patients with G1 and a tumor diameter less than 4 cm, if the tumor was located over 3 mm from the pancreatic duct, enucleation may be a wise choice.

Pancreatic Neuroendocrine Neoplasms in Multiple Endocrine Neoplasia Type 1.

Pancreatic neuroendocrine tumors (pNETs) are a rare group of cancers accounting for about 1-2% of all pancreatic neoplasms. About 10% of pNETs arise within endocrine tumor syndromes, such as Multiple Endocrine Neoplasia type 1 (MEN1). pNETs affect 30-80% of MEN1 patients, manifesting prevalently as multiple microadenomas. pNETs in patients with MEN1 are particularly difficult to treat due to differences in their growth potential, their multiplicity, the frequent requirement of extensive surgery, the high rate of post-operative recurrences, and the concomitant development of other tumors. MEN1 syndrome is caused by germinal heterozygote inactivating mutation of the MEN1 gene, encoding the menin tumor suppressor protein. MEN1-related pNETs develop following the complete loss of function of wild-type menin. Menin is a key regulator of endocrine cell plasticity and its loss in these cells is sufficient for tumor initiation. Somatic biallelic loss of wild-type menin in the neuroendocrine pancreas presumably alters the epigenetic control of gene expression, mediated by histone modifications and DNA hypermethylation, as a driver of MEN1-associated pNET tumorigenesis. In this light, epigenetic-based therapies aimed to correct the altered DNA methylation, and/or histone modifications might be a possible therapeutic strategy for MEN1 pNETs, for whom standard treatments fail.

Function and clinical relevance of RHAMM isoforms in pancreatic tumor progression.

The receptor for hyaluronic acid-mediated motility (RHAMM) is upregulated in various cancers. We previously screened genes upregulated in human hepatocellular carcinomas for their metastatic function in a mouse model of pancreatic neuroendocrine tumor (PNET) and identified that human RHAMMB promoted liver metastasis. It was unknown whether RHAMMB is upregulated in pancreatic cancer or contributes to its progression. In this study, we found that RHAMM protein was frequently upregulated in human PNETs. We investigated alternative splicing isoforms, RHAMMA and RHAMMB, by RNA-Seq analysis of primary PNETs and liver metastases. RHAMMB, but not RHAMMA, was significantly upregulated in liver metastases. RHAMMB was crucial for in vivo metastatic capacity of mouse and human PNETs. RHAMMA, carrying an extra 15-amino acid-stretch, did not promote metastasis in spontaneous and experimental metastasis mouse models. Moreover, RHAMMB was substantially higher than RHAMMA in pancreatic ductal adenocarcinoma (PDAC). RHAMMB, but not RHAMMA, correlated with both higher EGFR expression and poorer survival of PDAC patients. Knockdown of EGFR abolished RHAMMB-driven PNET metastasis. Altogether, our findings suggest a clinically relevant function of RHAMMB, but not RHAMMA, in promoting PNET metastasis in part through EGFR signaling. RHAMMB can thus serve as a prognostic factor for pancreatic cancer.

Palliative Resection of Primary Tumor in Metastatic Nonfunctioning Pancreatic Neuroendocrine Tumors.

BACKGROUND: Whether primary tumor resection is beneficial in patients with metastatic nonfunctioning pancreatic neuroendocrine tumors (NF-pNETs) remains unclear. This study aimed to investigate whether palliative resection of primary tumor affected the survival of patients with stage IV NF-pNETs. METHODS: We collected data from patients with stage IV NF-pNET registered in the Surveillance, Epidemiology, and End Results database from 2004 to 2015. Risk-adjusted Cox proportional hazard regression analysis and propensity score-matched analysis were used to analyze overall survival (OS) and cancer-specific survival (CSS) of patients. RESULTS: In total, 1974 stage IV NF-pNETs patients were identified, of whom 392 (19.9%) received palliative primary tumor resection. The latter exhibited significantly prolonged OS (hazard ratio = 2.514, 95% confidence interval: 2.081-3.037, P < 0.001) and CSS (hazard ratio = 2.634, 95% confidence interval: 2.159-3.213, P < 0.001) in multivariate Cox regression analysis. According to propensity score-matched results, patients without primary tumor resection had worse OS and CSS. CONCLUSIONS: This study demonstrates that there is a significant correlation between palliative resection of primary tumor and survival benefit. Therefore, resection could be considered as an additional treatment option in this specific patient population.

MEG3 Suppresses Human Pancreatic Neuroendocrine Tumor Cells Growth and Metastasis by Down-Regulation of Mir-183.

BACKGROUND/AIMS: Pancreatic neuroendocrine tumors (pNETs) are rare neoplasms which arise from pancreatic islet cells. Recently, lncRNA MEG3 has been reported as a tumor suppressor in variety cancers. This study aimed to reveal the functional effects of MEG3 on pNETs which has not been uncovered previously. METHODS: The expression of MEG3, miR-183, and BRI3 in BON1 cells were altered by transfection with their specific vectors/shRNA, or mimic/inhibitor. Thereafter, cell viability, apoptosis, the protein expressions of cell cycle related factors, and apoptosis associated factors, as well as cell migration and invasion were respectively assessed by typan blue staining, flow cytometry, western blotting, and transwell assay. RESULTS: MEG3 was low expressed in BON1 and QGP-1 cells, when compared to three normal cell lines (HEK293, CCL-153, and EC-304). MEG3 overexpression decreased BON1 cells viability, invasion, migration, but significantly induced apoptosis. miR-183 was a direct target of MEG3, and miR-183 up-regulation abolished the anti-growth and anti-metastasis effects of MEG3 overexpression on BON1 cells. Moreover, BRI3 was a target of miR-183, and BRI3 exhibited a tumor-promoting role possibly via activation of p38/ERK/AKT and Wnt/ß-Catenin signaling in BON1 cells. CONCLUSION: This study demonstrated a tumor suppressive effect of MEG3 in BON1 cells that suppresses tumor cells growth and metastasis. A novel regulatory mechanism has been revealed that modulation of MEG3/miR-183/BRI3 axis may be pivotal in pNET.

Pancreatic neuroendocrine tumors: a review.

Neuroendocrine tumors (NETs) are a rare and heterogeneous group of tumors with widely varying morphologies and behaviors. Due to their rarity and heterogeneity, progress in improving their treatment has been slow. However, in recent years there have been advances both in their characterization and in the available treatment options. This review will attempt to address these, with particular reference to pancreatic NETs. Pancreatic NETs are a subset of NETs, previously known as islet cell tumors, which appear to be a distinct biological entity, responding differently to systemic treatments compared with NETs arising elsewhere in the GI tract.

Askin's Tumour: A Report of a Rare Case.

Primitive neuroectodermal tumours (PNETs) are rare, malignant tumours arising from primitive nerve cells. PNET of the chest wall is rare and is observed in children and young adults. Askin defined Askin's tumour as a PNET of the thoracopulmonary area. It develops from the soft tissues of the chest wall, particularly in the paravertebral region. Here, we report a case of Askin's tumour, a rare neoplasm occurring in the thoracopulmonary region in a 13-year-old girl. She came with complaints of fever, cold, cough with mucoid expectoration, breathlessness for 15 days, and generalized weakness for three months. A high-resolution computed tomography (HRCT) thorax scan was also done, which suggested a large right pleural-based mass with vertebral metastasis. Through diligent diagnostic evaluation involving imaging studies and histopathological examination, the tumour was accurately identified.

Radioimaging Presentation of a Primitive Neuroectodermal Tumor of the Lung in a 13-Year-Old Female: A Case Report.

Primitive neuroectodermal tumors (PNETs) are unprecedented threatening neoplasms beginning from primitive neuroectodermal cells. PNETs are reported as the predominant incidence observed in children and young adults with a high mortality rate. These neuroectodermal tumors are quite aggressive with a life expectancy of eight months on average. PNETs belong to the family of small round cell tumors majorly affecting bones and soft tissues in different body parts such as the brain, lungs, spine, and pelvic region. Computed tomography (CT) and magnetic resonance imaging (MRI) play a major role in giving the size, extent, and resectability of the tumors. A confirmed diagnosis is then made by histopathology and immunohistochemistry markers. This report depicts a case of PNET found within the right lung of a 13-year-old female, enumerating the clinical introduction, demonstrative handle, treatment modalities, and results. The case underscores the significance of precise conclusions and multidisciplinary approaches in pediatric PNET cases. Once the provisional diagnosis of pleuropulmonary blastoma or PNET was given on CT, a conformational histopathological examination was carried out. Histopathological analysis confirmed the final diagnosis of PNET, and the patient underwent neoadjuvant therapy as the tumor was non-resectable due to its massive size.

SCG2 and CPE may be novel markers for the identification of pancreatic neuroendocrine tumors and solid pseudopapillary neoplasms.

Background: Distinguishing pancreatic neuroendocrine tumors (pNETs) from solid pseudopapillary neoplasms (SPNs) is challenging, primarily due to their overlapping pathological characteristics. To address this, our study aims to identify and validate novel biomarkers that effectively differentiate between these two conditions. We focus on the exploration of new immunohistochemical markers to enhance this distinction. Methods: In this study, we analyzed genetic variations in pNETs and SPNs using the GSE43795 dataset from the Gene Expression Omnibus (GEO) database. Our approach was to identify genes with higher expression in pNETs compared to SPNs and normal pancreatic tissues. We conducted enrichment analyses to understand the functions of these genes. Furthermore, protein-protein interaction (PPI) network analysis was utilized to identify key genes associated with pNETs. Our sample consisted of 163 pancreatic tumor specimens, comprising 78 pNETs and 85 SPNs. We also collected clinicopathological data and used immunohistochemistry to measure the expression levels of these key genes. Results: The enrichment analysis revealed that genes overexpressed in pNETs were mainly involved in signal release, vesicle transport, and ion pathway activation, playing significant roles in endocrine processes like insulin secretion, dopamine synapses, and circadian rhythm regulation. The PPI analysis identified secretogranin II (SCG2), carboxypeptidase E (CPE), and chromogranin A (CgA, CHGA) as key markers for differentiating pNETs from SPNs. Immunohistochemical validation of these markers demonstrated high sensitivity (SCG2: 98.7%, CPE: 97.4%) and specificity (100%), indicating their superior discriminative power compared to traditional markers like CgA, ß-catenin, lymphoid enhancer-binding factor 1 (LEF1), and vimentin. Conclusions: Our study indicates that SCG2 and CPE are effective, novel immunohistochemical biomarkers for differentiating pNETs from SPNs.

When Should Lymphadenectomy Be Performed in Non-Metastatic Pancreatic Neuroendocrine Tumors? A Population-Based Analysis of the German Clinical Cancer Registry Group.

BACKGROUND: Patient selection for lymphadenectomy remains a controversial aspect in the treatment of pancreatic neuroendocrine tumors (pNETs), given the growing importance of parenchyma-sparing resections and minimally invasive procedures. METHODS: This population-based analysis was derived from the German Cancer Registry Group during the period from 2000 to 2021. Patients with upfront resected non-functional non-metastatic pNETs were included. RESULTS: Out of 5520 patients with pNET, 1006 patients met the inclusion criteria. Fifty-three percent of the patients were male. The median age was 64 ± 17 years. G1, G2, and G3 pNETs were found in 57%, 37%, and 7% of the patients, respectively. Lymph node metastasis (LNM) was present in 253 (24%) of all patients. LNM was an independent prognostic factor (HR 1.79, CI 95% 1.21-2.64, p = 0.001) for disease-free survival (DFS). The 3-, 5-, and 10-year disease-free survival in nodal negative tumors compared to nodal positive was 82% vs. 53%, 75% vs. 38%, and 48% vs. 16%. LNM was present in 5% of T1 tumors, 25% of T2 tumors, and 49% of T3-T4 tumors. In T1 tumors, G1 was the most predominant tumor grade (80%). However, in T2 tumors, G2 and G3 represented 44% and 5% of all tumors. LNM was associated with tumors located in the pancreatic head (p < 0.001), positive resection margin (p < 0.001), tumors larger than 2 cm (p < 0.001), and higher tumor grade (p < 0.001). The multivariable analysis showed that tumor size, tumor grade, and location were independent prognostic factors associated with LNM that could potentially be used to predict LNM preoperatively. CONCLUSION: LNM is an independent negative prognostic factor for DFS in pNETs. Due to the low incidence of LNM in T1 tumors (5%), parenchyma-sparing surgery seems oncologically adequate in small G1 pNETs, while regional lymphadenectomy should be recommended in T2 or G2/G3 pNETs.

Contrast-enhanced ultrasound (CEUS) and shear wave elastography (SWE) features for characterizing serous microcystic adenomas (SMAs): In comparison to pancreatic neuroendocrine tumors (pNETs).

Objectives: Serous microcystic adenoma (SMA), a primary benign pancreatic tumor which can be clinically followed-up instead of undergoing surgery, are sometimes mis-distinguished as pancreatic neuroendocrine tumor (pNET) in regular preoperative imaging examinations. This study aimed to analyze preoperative contrast-enhanced ultrasound (CEUS) and shear wave elastography (SWE) features of SMAs in comparison to pNETs. Material and methods: In this retrospective study, patients with imaging-diagnosed pancreatic lesions were screened between October 2020 to October 2022 (ethical approval No. B2020-309R). Performing by a Siemens Sequoia (Siemens Medical Solutions, Mountain View, CA, USA) equipped with a 5C-1 curved array transducer (3.0-4.5 MHz), CEUS examination was conducted to observe the microvascular perfusion patterns of pancreatic lesions in arterial phase, venous/late phases (VLP) using SonoVue® (Bracco Imaging Spa, Milan, Italy) as the contrast agent. Virtual touch tissue imaging and quantification (VTIQ) - SWE was used to measure the shear wave velocity (SWV, m/s) value to represent the quantitative stiffness of pancreatic lesions. Multivariate logistic regression was performed to analyze potential ultrasound and clinical features in discriminating SMAs and pNETs. Results: Finally, 30 SMA and 40 pNET patients were included. All pancreatic lesions were pathologically proven via biopsy or surgery. During the arterial phase of CEUS, most SMAs and pNETs showed iso- or hyperenhancement (29/30, 97 % and 31/40, 78 %), with a specific early honeycomb enhancement pattern appeared in 14/30 (47 %) SMA lesions. During the VLP, while most of the SMA lesions remained iso- or hyperenhancement (25/30, 83 %), nearly half of the pNET lesions revealed an attenuated hypoenhancement (17/40, 43 %). The proportion of hypoenhancement pattern during the VLP of CEUS differed significantly between SMAs and pNETs (P = 0.021). The measured SWV value of SMAs was significantly higher than pNETs (2.04 ± 0.70 m/s versus 1.42 ± 0.44 m/s, P = 0.002). Taking a SWV value > 1.83 m/s as a cutoff in differentiating SMAs and pNETs, the area under the receiver operating characteristic curve (AUROC) was 0.825, with sensitivity, specificity and likelihood ratio (+) of 85.71 %, 72.73 % and 3.143, respectively. Multivariate logistic regression revealed that SWV value (m/s) of the pancreatic lesion was an independent variable in discriminating SMA and pNET. Conclusion: By comprehensively evaluating CEUS patterns and SWE features, SMA and pNET may be well differentiated before the operation. While SMA typically presents as harder lesion in VTIQ-SWE, exhibiting a specific honeycomb hyperenhancement pattern during the arterial phase of CEUS, pNET is characterized by relative softness, occasionally displaying a wash-out pattern during the VLP of CEUS.

An integrative view on glucagon function and putative role in the progression of pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC).

Cancer metabolism research area evolved greatly, however, is still unknown the impact of systemic metabolism control and diet on cancer. It makes sense that systemic regulators of metabolism can act directly on cancer cells and activate signalling, prompting metabolic remodelling needed to sustain cancer cell survival, tumour growth and disease progression. In the present review, we describe the main glucagon functions in the control of glycaemia and of metabolic pathways overall. Furthermore, an integrative view on how glucagon and related signalling pathways can contribute for pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC) progression, since pancreas and liver are the major organs exposed to higher levels of glucagon, pancreas as a producer and liver as a scavenger. The main objective is to bring to discussion some glucagon-dependent mechanisms by presenting an integrative view on microenvironmental and systemic aspects in pNETs and HCC biology.

Von Hippel-Lindau is Associated to Pancreatic Neuroendocrine Tumors: A Comprehensive Review.

Multiorgan tumors are a hallmark of the autosomal dominant genetic disorder known as Von Hippel-Lindau syndrome (VHL), which is typically the result of inherited aberrations of the VHL tumor suppressor gene. The most frequent cancer is retinoblastoma, which can also occur in the brain and spinal cord, renal clear cell carcinoma (RCCC), paraganglioma, and neuroendocrine tumors. There may also be lymphangiomas, epididymal cysts, and pancreatic cysts or pancreatic neuroendocrine tumors (pNETs). The most frequent causes of death are metastasis from RCCC and neurological complications from retinoblastoma or central nervous system (CNS). Pancreatic cysts are present in 35-70% of VHL patients. Simple cysts, serous cysts, or pNETs are possible presentations, and the likelihood of malignant degeneration or metastasis is no greater than 8%. Although VHL has been associated with pNETs, their pathological characteristics are unknown. Furthermore, it is unknown whether variations in the VHL gene cause the development of pNETs. Hence, this retrospective study was undertaken with the main aim to examine whether pNETs are connected to VHL from a surgical perspective.

Characteristics of small pancreatic neuroendocrine tumors and risk factors for invasion and metastasis.

Background: The number of people with small pancreatic neuroendocrine tumors (pNETs) (tumors with a diameter less than or equal to 2 cm) is gradually increasing, but the selection of treatment strategy is still controversial. Our aim was to characterize small pNETs with a poor prognosis and to define the impact of aggressive small pNETs on survival and the risk factors for the development of invasive disease. Methods: Patients with pNETs diagnosed between 2004 and 2019 and a tumor diameter of 2 cm or less were selected from the SEER Registry. Kaplan-Meier survival analysis was used to identify the factors affecting patient survival, and binary logistic regression was used to identify the associated risk factors. Results: A total of 3261 patients with pNETs were enrolled in the study. Both older and younger patients benefited from surgery. Regional invasion occurred in 10% of the patients, and distant metastases occurred in 9% of the patients, but in both categories, those who underwent surgery had better survival outcomes than those who did not. There was no difference in survival between patients with a tumor diameter of 1-2 cm and those with a tumor diameter of less than 1 cm, and there was no difference in survival between patients with functional and nonfunctional small pNETs. However, the survival of patients with pNETs in the head of the pancreas was worse than that of patients with tumors in other parts of the pancreas. Survival was worse in elderly patients and in those with poorly differentiated and undifferentiated tumors. Lymphatic metastasis, regional invasion, and distant metastasis all worsened the prognosis of patients. The presence or absence of neuroendocrine function, the degree of tumor differentiation, and the location of the tumor were associated with the risk of lymphatic metastasis and regional invasion; the risk factors for distant metastasis were associated with the degree of differentiation and tumor location. Conclusion: The pNETs ≤ 2 cm in diameter could be still aggressive, and patient prognosis worsens after invasive disease develops. Attention to the characteristics of aggressive tumors can improve patient survival.

Differential diagnosis between pancreatic solid pseudopapillary tumors and pancreatic neuroendocrine tumors based on contrast enhanced ultrasound imaging features.

PURPOSES: To evaluate the application of contrast enhanced ultrasound (CEUS) in preoperatively differential diagnosis between pancreatic solid pseudopapillary tumors (SPTs) and pancreatic neuroendocrine tumors (pNETs). PATIENTS AND METHODS: This retrospective study was approved by Institutional Review Board. Patients with surgical resection and histopathological diagnosis as SPTs and pNETs were included. All patients underwent B mode ultrasound (BMUS) and CEUS examinations within one week before surgical operation. On BMUS, the size, location, echogenicity, calcification, and margin of lesions were observed and recorded. On CEUS imaging, enhancement patterns, and enhancement degrees were recorded and analyzed. An independent t-test or Mann-Whitney U test was used for comparison between continuous variables. Chi-square test was used to compare the CEUS patterns. RESULTS: From February 2017 to Dec 2022, patients diagnosed as SPTs (n = 39) and pNETs (n = 48) were retrospectively included. On BMUS, anechoic cystic changes (19/39, 48.72%) and hyperechoic calcification (14/39, 35.90%) are more commonly detected in SPTs (P = 0.000). On CEUS imaging, the majority of SPTs (27/39, 69.23%) showed hypo-enhancement in the arterial phase, while most of the pNETs (36/48, 75.00%) showed hyper- or iso-enhancement in the arterial phase (P = 0.000). In the venous phase, most of the SPTs (32/39, 82.05%) showed hypo-enhancement, while over half of pNETs (29/48, 60.42%) showed hyper- or iso-enhancement compared to pancreatic parenchyma (P = 0.001). CONCLUSIONS: CEUS is a valuable and non-invasive imaging method to make preoperatively differential diagnoses between SPTs and pNETs.

Management Dilemma: Is Enucleation With Lymphadenectomy a Viable Choice for Large Pancreatic Neuroendocrine Tumors (p-NETs)?

Managing pancreatic neuroendocrine tumors (pNETs) has gradually taken a trend toward conservative management owing to its slow-growing and prolonged course. Though clear criteria exist regarding managing small tumors, the direction of a large tumor remains a dilemma. We present a case of a young 26-year-old lactating woman with a large 3.4 cm × 3.2 cm mass in the uncinate process, which is adjacent to the inferior vena cava (IVC) and has flimsy adhesions to the duodenum. She also had an enhancing adjacent lymph node measuring 1.2 cm × 0.7 cm, which showed enhancement with Ga-68 DOTANOC positron emission tomography/computed tomography (PET/CT) and raised serum gastrin levels. The dilemma was between pancreaticoduodenectomy (PD) or enucleation with lymphadenectomy (EL). Finally, EL was conducted. We discussed this case with relevant studies, which we had referred to because large-sized tumors are not usually enucleated.

Role of Advanced Gastrointestinal Endoscopy in the Comprehensive Management of Neuroendocrine Neoplasms.

Neuroendocrine neoplasms (NENs), also called neuroendocrine tumors (NETs), are relatively uncommon, heterogenous tumors primarily originating in the gastrointestinal tract. With the improvement in technology and increasing use of cross-sectional imaging and endoscopy, they are being discovered with increasing frequency. Although traditionally considered indolent tumors with good prognoses, some NENs exhibit aggressive behavior. Timely diagnosis, risk stratification, and management can often be a challenge. In general, small NENs without local invasion or lymphovascular involvement can often be managed using minimally invasive advanced endoscopic techniques, while larger lesions and those with evidence of lymphovascular invasion require surgery, systemic therapy, or a combination thereof. Ideal management requires a comprehensive and accurate understanding of the stage and grade of the tumor. With the recent advancements, a therapeutic advanced endoscopist can play a pivotal role in diagnosing, staging, and managing this rare condition. High-definition white light imaging and digital image enhancing technologies like narrow band imaging (NBI) in the newer endoscopes have improved the diagnostic accuracy of traditional endoscopy. The refinement of endoscopic ultrasound (EUS) over the past decade has revolutionized the role of endoscopy in diagnosing and managing various pathologies, including NENs. In addition to EUS-directed diagnostic biopsies, it also offers the ability to precisely assess the depth of invasion and lymphovascular involvement and thus stage NENs accurately. EUS-directed locoregional ablative therapies are increasingly recognized as highly effective, minimally invasive treatment modalities for NENs, particularly pancreatic NENs. Advanced endoscopic resection techniques like endoscopic submucosal dissection (ESD), endoscopic submucosal resection (EMR), and endoscopic full-thickness resection (EFTR) have been increasingly used over the past decade with excellent results in achieving curative resection of various early-stage gastrointestinal luminal lesions including NENs. In this article, we aim to delineate NENs of the different segments of the gastrointestinal (GI) tract (esophagus, gastric, pancreatic, and small and large intestine) and their management with emphasis on the endoscopic management of these tumors.