Surgical resection of double advanced pancreatic neuroendocrine tumors with multiple renal cell carcinoma associated with von Hippel-Lindau disease

Von Hippel-Lindau (VHL) disease, an autosomal dominant genetic disorder caused by a germline mutation, is associated with non-functional and slow-growing pancreatic neuroendocrine tumor (PNET) and kidney cancer. We describe the case of a 46 year-old man with a 35 mm mass in the pancreatic head causing stricture of the bile duct and main pancreatic duct, a 55 mm mass in the pancreatic tail causing obstruction of the splenic vein (SV), and multiple masses of > 36 mm on both kidneys. We performed a two-stage resection. First, a total pancreatectomy with superior mesenteric vein (SMV) resection and reconstruction and retroperitoneoscopic right partial nephrectomy (NP) for five lesions was performed, followed by retroperitoneoscopic left partial NP of the five lesions 6 months later. Postoperative histopathological examination revealed NET G2 in the pancreatic head with SMV invasion and somatostatin receptor type 2A (SSTR2A) positivity, NET G2 in the pancreatic tail showed SV invasion and negative SSTR2A, and multiple clear cell renal cell carcinomas (RCC) were also noted. Multiple liver recurrences occurred 22 months after primary surgery. The patient remains alive 41 months after primary surgery. Kidney cancer generally determines VHL prognosis; however, we experienced dual-advanced PNETs with a more defined prognosis than multiple RCC associated with VHL.

Long-term Follow-up of Small Nonfunctioning Pancreatic Neuroendocrine Tumors Diagnosed Using Endoscopic Ultrasound-guided Fine-needle Aspiration

Objective Clinical practice guidelines in Japan recommend surgery for all nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs), regardless of their size or associated symptoms. Because pancreatic resection is highly invasive, follow-up for small NF-PNETs is often chosen in clinical practice. However, the natural history of NF-PNET remains poorly understood. We aimed to examine the natural history of pathologically confirmed NF-PNET. Methods This single-center retrospective case series investigated NF-PNETs that were pathologically diagnosed using endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) at our hospital between 2014 and 2018. Patients who were followed up without treatment due to their general condition or their wish were included in the study. Patients' background characteristics, imaging findings, pathological findings, and long-term prognoses were investigated using medical records. Results Overall, 26 patients were diagnosed with NF-PNET by EUS-FNA during the observation period. Of these, 9 patients (3 men and 6 women; median age: 64 years old) were followed up without treatment. All of these patients were asymptomatic, and localization was noticed in 3 cases in the head, body, and tail (1 each), with a median size of 12 (range: 4-18) mm. Neuroendocrine tumor (Grade 1 [G1]) was pathologically diagnosed in all patients with EUS-FNA. The median observation period was 63 (range: 26-90) months. Tumor growth and distant metastasis were not observed in any of the nine patients who remained asymptomatic. Conclusion Follow-up is a feasible option for asymptomatic NF-PNET ≤20 mm in size with a pathological grade of G1.

Optimal Lymphadenectomy in Patients with Well-Differentiated Nonfunctioning Pancreatic Neuroendocrine Neoplasms

This study aimed to evaluate the optimal extent of lymphadenectomy in patients with nonfunctioning pancreatic neuroendocrine neoplasms. We retrospectively analyzed the clinicopathological data of patients with nonfunctioning pancreatic neuroendocrine neoplasms who underwent surgical resection. We investigated the frequency of metastases at each lymph node station according to tumor location and analyzed the factors contributing to poor overall survival (OS) and disease-free survival (DFS). Overall, data of 84 patients were analyzed. Among patients with pancreatic head tumors, metastases at stations 8, 13, and 17 were found in one (3.1%), four (12.5%), and three (9.3%) patients, respectively. However, none of the other stations showed metastases. For pancreatic body and tail tumors, metastases only at station 11 were found in two (5.1%) patients. Additionally, multivariate DFS and OS analyses showed that lymph node metastasis was the only independent prognostic factor. In conclusion, lymph node metastasis near the primary tumor was the only independent factor of poor prognosis in patients with nonfunctioning pancreatic neuroendocrine neoplasms after undergoing curative surgery. Peri-pancreatic lymphadenectomy might be recommended for nonfunctioning pancreatic neuroendocrine neoplasms.

Neuroendocrine tumor of the minor duodenal papilla with lymph node metastasis: a case report and literature review

Whether pancreatoduodenectomy or papillary resection should be performed to achieve curative treatment for neuroendocrine tumors of the minor duodenal papilla with a diameter of ≤2 cm is controversial. We report a 35-year-old male patient with a rare case of a neuroendocrine tumor of the minor duodenal papilla. The patient was referred to our hospital from a different clinic for dilatation of his minor duodenal papilla. Duodenoscopy revealed a smooth mass of 2 cm in diameter in the minor papilla, and the biopsy specimen was diagnosed as neuroendocrine tumor G1. The patient underwent subtotal stomach-preserving pancreatoduodenectomy. Histological evaluation showed a single nodule of 15 mm in diameter in the mucosa with metastasis to the regional lymph node. The tumor cells exhibited immunoactivity against synaptophysin and chromogranin A. The molecular immunology Borstel-1 index was less than 1%, and the grade was neuroendocrine tumor G1. We reviewed the characteristics of 24 cases of patients who underwent PD for NETs of the minor duodenal papilla in English literature. In 22 of these cases, the tumor depth was described. Lymph node metastasis was observed in none of the three cases (0%) in which the tumor was limited to the intra-sphincter; however, it was noted in three (30%) of the 10 cases in which the tumor had invaded the duodenal submucosa and in eight (89%) of the nine cases in which the tumor had invaded the muscularis propria, pancreas, peripancreatic/periduodenal tissues, or duodenal serosa. Making a definitive diagnosis preoperatively or intraoperatively whether the tumor invades beyond the sphincter or not and whether regional lymph node metastasis is present may not be possible. Therefore, we believe that pancreatoduodenectomy with lymphadenectomy is preferable for curative treatment of neuroendocrine tumors of the minor duodenal papilla.

Clinicoradiological Factors Predicting Lymph Node Metastasis in Patients with Nonfunctioning Pancreatic Neuroendocrine Neoplasms: A Systematic Review and Meta-Analysis

INTRODUCTION

Lymph node metastasis of nonfunctioning pancreatic neuroendocrine neoplasms (pNENs) potentially leads to poor survival. Given the contradictory results in the literature regarding factors associated with lymph node metastasis of nonfunctioning pNENs, we conducted a systematic review and meta-analysis to determine the preoperative predictors of lymph node metastasis.

METHODS

Original studies reporting factors associated with lymph node metastasis in patients with nonfunctioning pNENs were identified in PubMed, EMBASE, and Cochrane Library databases, and data from eligible studies were analyzed using random-effects meta-analysis to obtain pooled estimates of odds ratios (ORs) and their 95% confidence intervals (CIs).

RESULTS

Eleven studies were included. Tumor size (>2 cm or >2.5 cm; OR, 5.80 [95% CI, 4.07-8.25]) and pancreatic head location (OR, 1.75 [95% CI, 1.05-2.94]) were significant preoperative predictors of lymph node metastasis. Old age (OR, 1.07 [95% CI, 0.68-1.68]) and male sex (OR, 1.12 [95% CI, 0.74-1.70]) were not significantly associated with lymph node metastasis.

CONCLUSIONS

A large tumor size and pancreatic head location can be useful for planning optimal treatment in patients with nonfunctioning pNENs.

Efficacy of endoscopic ultrasound-guided tissue acquisition for solid pancreatic lesions 20 mm or less in diameter suspected as neuroendocrine tumors or requiring differentiation

BACKGROUND

For non-functioning pancreatic neuroendocrine tumors (pNETs) ≤ 20 mm, most guidelines consider follow-up observations as an option; however, the various treatment strategies are defined by size alone, even though the Ki-67 index is important for malignancy grading. Endoscopic ultrasound-guided tissue acquisition (EUS-TA) is the standard for the histopathological diagnosis of solid pancreatic lesions; however, recent results for small lesions remain unclear. Therefore, we examined the efficacy of EUS-TA for solid pancreatic lesions ≤ 20 mm suspected as pNETs or requiring differentiation and the non-increase rate in tumor size in follow-up cases.

METHODS

We retrospectively analyzed data of 111 patients (median age = 58 years) with lesions ≤ 20 mm suspected as pNETs or requiring differentiation who underwent EUS-TA. All patients underwent specimen evaluation by rapid onsite evaluation (ROSE).

RESULTS

EUS-TA led to a diagnosis of pNETs in 77 patients (69.4%) and tumors other than pNETs in 22 patients (19.8%). The histopathological diagnostic accuracy of EUS-TA was 89.2% (99/111) overall, 94.3% (50/53) for 10-20 mm lesions, and 84.5% (49/58) for ≤ 10 mm lesions, with no significant difference in diagnostic accuracy (p = 0.13). The Ki-67 index was measurable in all patients with a histopathological diagnosis of pNETs. Among 49 patients with a diagnosis of pNETs who were followed up, one patient (2.0%) showed tumor enlargement.

CONCLUSIONS

EUS-TA for solid pancreatic lesions ≤ 20 mm suspected as pNETs or requiring differentiation is safe and has adequate histopathological diagnostic accuracy, suggesting that follow-up observations of pNETs with a histological pathologic diagnosis are acceptable in the short term.

Endoscopic ultrasound fine-needle biopsy to assess DAXX/ATRX expression and alternative lengthening of telomeres status in non-functional pancreatic neuroendocrine tumors

BACKGROUND/OBJECTIVES

Death domain-associated protein (DAXX) and/or α-thalassemia/mental retardation X-linked (ATRX) chromatin remodeling genes mutations and alternative lengthening of telomeres (ALT) activation are associated with more aggressive behavior of non-functional pancreatic neuroendocrine tumors (NF-PanNETs). We aimed to evaluate the reliability of such markers on endoscopic-ultrasound fine-needle biopsy (EUS-FNB) specimens.

METHODS

Patients who underwent EUS-FNB and subsequent surgical resection for PanNETs between January 2017 and December 2019 were retrospectively identified. Immunohistochemistry (IHC) to evaluate DAXX/ATRX expression and fluorescence in situ hybridization (FISH) for ALT status were performed. Primary outcome was the concordance rate of markers expression between EUS-FNB and surgical specimens. Secondary aims were association between markers and lesion aggressiveness, their diagnostic performance in predicting aggressiveness, and agreement of preoperative and post-surgical Ki67-based grading.

RESULTS

Forty-one NF-PanNETs (mean diameter 36.1 ± 26.5 mm) were included. Twenty-four showed features of lesion aggressiveness. Concordance of expressions of DAXX, ATRX, and ALT status between EUS-FNB and surgical specimens were 95.1% (κ = 0.828; p < 0.001), 92.7% (κ = 0.626; p < 0.001), and 100% (κ = 1; p < 0.001), respectively. DAXX/ATRX loss and ALT-positivity were significantly (p < 0.05) associated with metastatic lymphnodes and lymphovascular invasion. The combination of all tumor markers (DAXX/ATRX loss + ALT-positivity + grade 2) reached an accuracy of 73.2% (95%CI 57.1-85.8) in identifying aggressive lesions. Pre- and post-operative ki-67-based grading was concordant in 80.5% of cases (k = 0.573; p < 0.001).

CONCLUSION

DAXX/ATRX expression and ALT status can be accurately evaluated in a preoperative setting on EUS-FNB samples, potentially improving the identification of patients with increased risk and poorer prognosis.

Prognostic role and predictors of lymph node involvement in pancreatic neuroendocrine tumors

PURPOSE

To define the prognostic role of lymph node involvement (LNI) in patients with pancreatic neuroendocrine tumors (PNETs) and identify predictors of LNI using a comprehensive multifactor analysis focusing on preoperative radiological features.

METHODS

This study included 236 patients with preoperative computed tomography who underwent radical surgical resection of PNETs at our hospital between 2009 and 2019. Univariate and multivariable logistic regression analyses were performed to investigate the risk factors associated with LNI and tumor recurrence. The disease-free survival (DFS) rates with and without LNI were compared.

RESULTS

Forty-four of the 236 patients (18.6%) had LNI. Biliopancreatic duct dilatation (odds ratio [OR], 2.295; 95% confidence interval [CI], 1.046-5.035; p = 0.038), tumor margin (OR, 2.189; 95% CI, 1.034-4.632; p = 0.041), and WHO grade (G2: OR, 2.923; 95% CI, 1.005-8.507; p = 0.049; G3: OR, 12.067; 95% CI, 3.057-47.629; p < 0.001) were independent risk factors of LNI in PNETs. Multivariable analysis showed that LNI (OR, 2.728; 95% CI, 1.070-6.954; p = 0.036), G3 (OR, 4.894; 95% CI, 1.047-22.866; p = 0.044), and biliopancreatic duct dilatation (OR, 2.895; 95% CI, 1.124-7.458; p = 0.028) were associated with PNET recurrence in patients after surgery. Patients with LNI had a significantly worse DFS than those without LNI (3-year DFS: 85.9 vs. 96.7%; p < 0.001; 5-year DFS: 65.1 vs. 93.9%; p < 0.001).

CONCLUSION

LNI was associated with decreased DFS. Biliopancreatic duct dilatation, irregular tumor margins, and grades G2 and G3 were independent risk factors for LNI.

Preoperative acute pancreatitis and hyperenzymemia are associated with poor prognosis in patients with nonfunctional pancreatic neuroendocrine tumors

BACKGROUND

We aimed to investigate the prevalence of acute pancreatitis (AP) and hyperenzymemia as well as their clinical impact on postoperative survival outcomes in patients with pancreatic neuroendocrine tumors (PNETs).

METHODS

A retrospective cohort study of 218 patients who underwent radical surgical resection for nonfunctional PNETs (NF-PNETs) was conducted. Multivariate survival analysis was performed by the Cox proportional hazard model, with results expressed as hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

Of the 151 patients who met the inclusion criteria, the incidences of preoperative AP and hyperenzymemia were 7.9% (12/152) and 23.2% (35/151), respectively. The mean recurrence-free survival (RFS, 95% CI) for patients in control, AP, and hyperenzymemia groups was 136 (127-144), 88 (74-103), and 90 (61-122) months, with a 5-year RFS rate of 86.5%, 58.3%, and 68.9%, respectively. In the multivariable-adjusted Cox hazard model that included tumor grade and lymph node status, the adjusted HR of AP and hyperenzymemia for recurrence was 2.58 (95% CI: 1.47-7.86, p = 0.008) and 2.43 (95% CI: 1.08-7.06, p = 0.040).

CONCLUSION

Preoperative AP and hyperenzymemia are associated with poor RFS following radical surgical resection in NF-PNETs patients.

Reappraisal of Malignant Risk Assessment for Small (≤20 mm) Non-functioning Pancreatic Neuroendocrine Tumors

BACKGROUND

Optimal management of non-functioning pancreatic neuroendocrine tumors (PanNETs) ≤20 mm is controversial. The biological heterogeneity of these tumors poses challenges when deciding between resection and observation.

METHODS

In this multicenter, retrospective cohort study, we analyzed all patients (n = 78) who underwent resection of non-functioning PanNETs ≤20 mm at three tertiary medical centers from 2004 to 2020 to assess the utility of preoperatively available radiological features and serological biomarkers of non-functioning PanNETs in choosing an optimal surgical indication. The radiological features included non-hyper-attenuation pattern on enhancement computed tomography (CT; hetero/hypo-attenuation) and main pancreatic duct (MPD) involvement, and serological biomarkers included elevation of serum elastase 1 and plasma chromogranin A (CgA) levels.

RESULTS

Of all small non-functioning PanNETs, 5/78 (6%) had lymph node metastasis, 11/76 (14%) were WHO grade II, and 9/66 (14%) had microvascular invasion; 20/78 (26%) had at least one of these high-risk pathological factors. In the preoperative assessment, hetero/hypo-attenuation and MPD involvement were observed in 25/69 (36%) and 8/76 (11%), respectively. Elevated serum elastase 1 and plasma CgA levels were observed in 1/33 (3%) and 0/11 (0%) patients, respectively. On multivariate logistic regression analysis, hetero/hypo-attenuation (odds ratio [OR] 6.1, 95% confidence interval [CI] 1.7-22.2) and MPD involvement (OR 16.8, 95% CI 1.6-174.3) were significantly associated with the high-risk pathological factors. The combination of the two radiological worrisome features correctly predicted non-functioning PanNETs with high-risk pathological factors, with about 75% sensitivity, 79% specificity, and 78% accuracy.

CONCLUSIONS

This combination of radiological worrisome features can accurately predict non-functioning PanNETs that may require resection.

Management of Small Nonfunctioning Pancreatic Neuroendocrine Neoplasms: Current Opinion and Controversies

The incidence of small and asymptomatic pancreatic neuroendocrine neoplasms (PNENs) has increased due to the widespread use of high-resolution diagnostic imaging in screening programs. Most PNENs are slow-growing indolent neoplasms. However, a local invasion or metastasis can sometimes occur with PNENs, leading to a poor prognosis. The management of small, nonfunctioning PNENs remains under debate. The National Comprehensive Cancer Network guidelines recommend observation in selected cases of small PNENs less than 2 cm. Pancreatic surgery remains a high-risk operation with a 28-30% morbidity and 1% mortality. Therefore, the decision on how to manage small PNENs is challenging. This review focuses on the management of small nonfunctioning PNENs. We also highlight the malignant potential of small PNENs according to tumor size, tumor grade, and tumor biomarker. Endoscopic-ultrasound-guided biopsy is recommended to evaluate the potential risk of malignancy. Furthermore, we discuss the current guidelines and future directions for the management of small PNENs.

Pancreatic neuroendocrine neoplasms: a 2022 update for radiologists

Pancreatic neuroendocrine neoplasms (PaNENs) are a unique group of pancreatic neoplasms with a wide range of clinical presentations and behaviors. Given their heterogeneous appearance and increasing detection on cross-sectional imaging, it is essential that radiologists understand the variable presentation and distinctions PaNENs display compared to other pancreatic neoplasms. Additionally, some of these neoplasms may be hormonally functional, and it is imperative that radiologists be aware of the common clinical presentations of hormonally active PaNENs. Knowledge of PaNEN pathology and treatments may influence which imaging modality is optimal for each patient. Each imaging modality used for PaNENs has distinct advantages and disadvantages, particularly in different treatment settings. Thus, the focus of this manuscript is to provide an update for the radiologist on PaNEN pathology, imaging, and treatments.

Serotonin-positive neuroendocrine neoplasm with pancreatic ductal dilation in which cytological immunostaining contributed to the diagnosis

A 52-year-old man was transported via an ambulance because of syncope and the passage of tarry stools, which had been noted the previous day. He was diagnosed with upper gastrointestinal bleeding from a gastric ulcer and underwent endoscopic hemostasis. Prior to endoscopy, abdominal computerized tomography performed for gastrointestinal bleeding revealed pancreatic duct dilation. After discharge, abdominal imaging revealed a strongly enhancing tumor (5 mm) with caudal pancreatic duct dilation. Endoscopic retrograde pancreatography revealed that the main pancreatic duct was interrupted at the body. Pancreatic juice cytology was class III, and additional immunostaining were positive for chromogranin A, synaptophysin, and serotonin, suggesting a pancreatic neuroendocrine neoplasm (NEN). Distal pancreatectomy was performed and a yellowish-white solid lesion was found in the pancreatic duct. Pathological examination revealed narrowing of the pancreatic duct, extensive stromal fibrosis, and proliferation of tumor cells with small round nuclei and eosinophilic vesicles. Furthermore, the immunostaining findings of the resected specimen corresponded with those of the cytology. A diagnosis of NEN G1 (WHO classification) with Ki-67 index < 1% was made. Imaging of the pancreatic duct tend to be normal or show no involvement of the duct in pancreatic neuroendocrine neoplasms; however, there have been a few reports of stenosis due to fibrosis around the pancreatic duct. Serotonin positivity was previously documented to be significantly higher in patients with fibrosis. In lesions with pancreatic ductal stenosis, the addition of immunostaining to pancreatic juice cytology was thought to be useful in differentiating pancreatic cancer from pNEN.

A New Preoperative Scoring System for Predicting Aggressiveness of Non-Functioning Pancreatic Neuroendocrine Neoplasms

The management of non-functioning pancreatic neuroendocrine neoplasms (NF-PanNENs) is still controversial. This study aimed to develop a new scoring system for treatment decisions at initial diagnosis based on the identification of the predictive factors for aggressive NF-PanNENs. Seventy-seven patients who had been pathologically diagnosed with NF-PanNENs were enrolled. We retrospectively reviewed 13 variables that could be assessed preoperatively. Univariate and multivariate stepwise logistic regression analyses were performed to identify factors for the aggressiveness of NF-PanNENs, and a scoring system was developed by assigning weighted points proportional to their β regression coefficient. Tumor size > 20 mm on contrast-enhanced computed tomography, tumor non-vascularity, and Ki-67 labeling index ≥5% on endoscopic ultrasound-guided fine-needle aspiration specimens were identified as independent factors for predicting the aggressiveness of NF-PanNENs. The new scoring system, developed using the identified factors, had an excellent discrimination ability, with area under the curve of 0.92 (95% CI, 0.85–0.99), and good calibration (p = 0.72, Hosmer-Lemeshow test). Ten-year overall survival rates in low-risk (0 point), intermediate-risk (1 to 2 points), and high-risk (3 to 4 points) groups were 100%, 90.9%, and 24.3%, respectively. This new scoring system would be useful for treatment decisions and prognostic prediction at initial diagnosis.

Preoperative risk stratification of lymph node metastasis for non-functional pancreatic neuroendocrine neoplasm: An international dual-institutional study

BACKGROUND

/Objectives: Although the presence of lymph node metastasis (LNM) defines malignant potential, preoperative prediction of LNM has not been established for non-functional pancreatic neuroendocrine neoplasm (NF-PNEN). We sought to develop a prediction system using only preoperatively available factors that would stratify the risk of LNM for NF-PNEN.

METHODS

We retrospectively reviewed patients who underwent R0/1 resection of NF-PNEN at Kyoto University (2007-2019) and the University of California, San Francisco (2010-2019). Risk stratification of LNM was developed using preoperative factors by the logistic regression analysis. Long-term outcomes were compared across the risk groups.

RESULTS

A total of 131 patients were included in this study. Lymph nodes were pathologically examined in 116 patients, 23 (20%) of whom had LNM. Radiological tumor size [1.5-3.5 cm (odds ratio: 13.5, 95% confidence interval: 1.77-398) and >3.5 cm (72.4, 9.06-2257) against ≤1.5 cm], <50% cystic component (8.46 × 10^6, 1.68 × 10^106-), and dilatation of main pancreatic duct ≥5 mm (31.2, 3.94-702) were independently associated with LNM. When patients were classified as the low-risk (43 patients), intermediate-risk (44 patients), and high-risk groups (29 patients), proportions of LNM differed significantly across the groups (0%, 14%, and 59%, respectively). Recurrence-free survival (RFS) of the low- and intermediate-risk groups were significantly better than that of the high-risk group (5-year RFS rates of 92.2%, 85.4%, and 47.1%, respectively).

CONCLUSIONS

The prediction system using preoperative radiological factors stratifies the risk of LNM for NF-PNEN. This stratification helps to predict malignant potential and determine the surgical procedure and necessity of regional lymphadenectomy.

What Are the Place and Modalities of Surgical Management for Pancreatic Neuroendocrine Neoplasms? A Narrative Review

Pancreatic neuroendocrine neoplasms (panNENs) are a heterogeneous group of tumors derived from cells with neuroendocrine differentiation. They are considered malignant by default. However, their outcomes are variable depending on their presentation in the onset of hereditary syndromes, hormonal secretion, grading, and extension. Therefore, although surgical treatment has long been suggested as the only treatment of pancreatic neuroendocrine neoplasms, its modalities are an evolving landscape. For selected patients (small, localized, non-functional panNENs), a "wait and see" strategy is suggested, as it is in the setting of multiple neuroendocrine neoplasia type 1, but the accurate size cut-off remains to be established. Parenchyma-sparring pancreatectomy, aiming to limit pancreatic insufficiency, are also emerging procedures, which place beyond the treatment of insulinomas and small non-functional panNENs (in association with lymph node picking) remains to be clarified. Furthermore, giving the fact that the liver is generally the only metastatic site, surgery keeps a place of choice alongside medical therapies in the treatment of metastatic disease, but its modalities and extensions are still a matter of debate. This narrative review aims to describe the current recommended surgical management for pancreatic NENs and controversies in light of the actual recommendations and recent literature.

Prognostic factors for relapse in resected gastroenteropancreatic neuroendocrine neoplasms: A systematic review and meta-analysis

BACKGROUND

Gastroenteropancreatic neoplasms (GEP-NENs)can potentially be cured through surgical resection, but only 42-57% achieve 5-year disease-free survival.There is a lack of consensus regarding the factorsassociated withrelapse followingresection ofGEP-NENs.

METHODS

Asystematic review identified studies reporting factors associated with relapse in patients with GEP-NENs following resection of a primary tumour. Meta-analysis was performed to identify the factors prognostic for relapse-free survival (RFS)oroverall survival (OS).

RESULTS

63 studies comprising 13,715 patients were included; 56 studies reported on pancreatic NENs (12,418 patients), 24 reported on patients with grade 1-2 tumours (4,735 patients). Median follow-up was 44.2 months, median RFS was 32 months. Pooling of multivariable analyses of GEP-NENs (all sites and grades) found the following factors predicted worse RFS (all p values < 0.05): vascular resection performed, metastatic disease resected, grade 2 disease, grade 3 disease, tumour size > 20 mm, R1 resection, microvascular invasion, perineural invasion, Ki-67 > 5% and any lymph node positivity. In a subgroup of studies comprising exclusively of grade 1-2 GEP-NENs, R1 resection, perineural invasion, grade 2 disease, any lymph node positivity and tumour size > 20 mm predicted worse RFS (all p values < 0.05). Few OSdata were available for pooling; in univariableanalysis(entire cohort), grade 2 predicted worse OS (p = 0.007), whileR1 resectiondid not (p = 0.14).

CONCLUSIONS

The factors prognostic for worse RFS following resection of a GEP-NEN identified in this meta-analysis could be included in post-curative treatment surveillance clinical guidelines and inform the stratification and inclusion criteria of future adjuvant trials.

A novel risk factor panel predicts early recurrence in resected pancreatic neuroendocrine tumors

BACKGROUND

Pancreatic neuroendocrine tumors (PanNETs) are indolent pancreatic tumors derived from neuroendocrine cells in pancreatic islets. To date, reliable predictors for identifying patients at high risk for recurrence after curative cancer resection are lacking. We aimed to determine independent predictors for high-risk PanNETs and patient outcomes after surgery.

METHODS

We analyzed relevant clinicopathological parameters in 319 consecutive patients of derivation cohort 1 and 106 patients of validation cohort 2 who underwent pancreatectomy and were diagnosed with PanNETs. Association of tumor characteristics with recurrence-free survival (RFS) and overall survival (OS) was evaluated using Cox regression.

RESULTS

PanNET grade 3 (G3), pancreatic duct dilatation, and perineural invasion were independent prognostic factors for RFS and were significantly associated with early recurrence (within 1.5 years) of PanNETs after curative resection (P = 0.019, P < 0.001, and P < 0.001, respectively). Using these factors, we established a novel risk factor panel (R-panel), which predicted early recurrence (P < 0.001, HR = 15.02, 95% CI 5.76-39.19). Predictive accuracy of this R-panel was favorable, with a C-index of 0.853, higher than AJCC TNM staging (0.713). We further built an integrated staging system combining R-panel scoring and TNM staging, which improved predictive probability of TNM staging. Finally, we showed that adjuvant therapy with long-acting somatostatin analogs (SSAs) significantly reduced postoperative recurrence (P < 0.001) and prolonged long-term survival (P = 0.021) in patients with the above risk factors.

CONCLUSION

We identified a novel risk factor panel, which includes PanNET G3, pancreatic duct dilatation, and perineural invasion; this panel predicted early recurrence of PanNETs after curative resection. Patients with these risk factors can benefit from adjuvant therapy with SSAs.

Endoscopic Ultrasound Features Associated with Malignancy and Aggressiveness of Nonhypovascular Solid Pancreatic Lesions: Results from a Prospective Observational Study

BACKGROUND AND STUDY AIMS

 On contrast-enhanced imaging studies, nonhypovascular (i. e., isovascular and hypervascular) patterns can be observed in solid pancreatic lesions (SPLs) of different nature, prognosis, and management. We aimed to identify endoscopic ultrasound (EUS) features of nonhypovascular SPLs associated with malignancy/aggressiveness. The secondary aims were EUS tissue acquisition (EUS-TA) outcome and safety in this setting of patients.

PATIENTS AND METHODS

 This prospective observational study included patients with nonhypovascular SPLs detected on cross-sectional imaging and referred for EUS-TA. Lesion features (size, site, margins, echotexture, vascular pattern, and upstream dilation of the main pancreatic duct) were recorded. Malignancy/aggressiveness was determined by evidence of carcinoma at biopsy/surgical pathology, signs of aggressiveness (perineural invasion, lymphovascular invasion, and/or microscopic tumor extension/infiltration or evidence of metastatic lymph nodes) in the surgical specimen, radiologic detection of lymph nodes or distant metastases, and/or tumor growth > 5 mm/6 months. Uni- and multivariate analyses were performed to assess the primary aim.

RESULTS

 A total of 154 patients with 161 SPLs were enrolled. 40 (24.8 %) lesions were defined as malignant/aggressive. Irregular margins and size > 20 mm were independent factors associated with malignancy/aggressiveness (p < 0.001, OR = 5.2 and p = 0.003, OR = 2.1, respectively). However, size > 20 mm was not significant in the subgroup of other-than-neuroendocrine tumor (NET) lesions. The EUS-TA accuracy was 92 %, and the rate of adverse events was 4 %.

CONCLUSION

 Irregular margins on EUS are associated with malignancy/aggressiveness of nonhypovascular SPLs. Size > 20 mm should be considered a malignancy-related feature only in NET patients. EUS-TA is safe and highly accurate for differential diagnosis in this group of patients.

Malignant potential of small pancreatic neuroendocrine neoplasm and its risk factors: A multicenter nationwide study

BACKGROUND

Pancreatic neuroendocrine neoplasms (PNENs) show heterogeneous biological behavior, and most small PNENs show indolent features. Consequently, selected cases can be considered for observation only, according to the National Comprehensive Cancer Network guideline, however, supporting clinical evidence is lacking. We investigated the clinical course of small PNENs and their risk factors for malignant potential.

METHODS

A total of 158 patients with small pathologically confirmed PNENs ≤2 cm in initial imaging were retrospectively enrolled from 14 institutions. The primary outcome was any metastasis or recurrence event during follow-up.

RESULTS

The median age was 57 years (range, 22-82 years), and 86 patients (54%) were female. The median tumor size at initial diagnosis was 13 mm (range, 7-20 mm). PNENs were pathologically confirmed by surgery in 137 patients and by EUS-guided fine needle aspiration biopsy (EUS-FNAB) in 21 patients. Eight patients underwent EUS-FNAB followed by surgical resection. The results of WHO grade were available in 150 patients, and revealed 123 grade 1, 25 grade 2, and 2 neuroendocrine carcinomas. A total of 145 patients (92%) underwent surgical resection, and three patients had regional lymph node metastasis. During the entire follow-up of median 45.6 months, 11 metastases or recurrences (7%) occurred. WHO grade 2 (HR 13.97, 95% CI 2.60-75.03, p = 0.002) was the only predictive factor for malignant potential in multivariable analysis.

CONCLUSIONS

WHO grade is responsible for the malignant potential of small PNENs ≤2 cm. Thus, EUS-FNAB could be recommended in order to provide early treatment strategies of small PNENs.

Pancreatic neuroendocrine tumor with stenosis of the main pancreatic duct leading to pancreatic pleural effusion: a case report

Background

Pancreatic pleural effusion and ascites are defined as fluid accumulation in the thoracic and abdominal cavity, respectively, due to direct leakage of the pancreatic juice. They usually occur in patients with acute or chronic pancreatitis but are rarely associated with pancreatic neoplasm. We present here an extremely rare case of pancreatic neuroendocrine tumor with stenosis of the main pancreatic duct, leading to pancreatic pleural effusion.

Case presentation

A 51-year-old man complained of dyspnea. Left-sided pleural effusion was detected on the chest X-ray. Pleural puncture was performed, and the pleural fluid indicated a high amylase content (36,854 IU/L). Hence, the patient was diagnosed with pancreatic pleural effusion. Although no tumor was detected, the computed tomography (CT) scan showed a pseudocyst and dilation of the main pancreatic duct in the pancreatic tail. Magnetic resonance cholangiopancreatography showed a fistula from the pseudocyst into the left thoracic cavity. Endoscopic retrograde pancreatic drainage was attempted; however, it failed due to stenosis in the main pancreatic duct in the pancreatic body. Endoscopic ultrasound revealed a hypoechoic mass measuring 15 × 15 mm in the pancreatic body that was not enhanced in the late phase of contrast perfusion and was thus suspected to be an invasive ductal carcinoma. The patient underwent distal pancreatectomy with splenectomy and the postoperative course was uneventful. Histopathological examination confirmed a neuroendocrine tumor of the pancreas (NET G2). The main pancreatic duct was compressed by the tumor. Increased pressure on the distal pancreatic duct by the tumor might have caused formation of the pseudocyst and pleural effusion. To the best of our knowledge, this is the first case report of pancreatic pleural effusion associated with a neuroendocrine tumor.

Conclusions

Differential diagnosis of a pancreatic neoplasm should be considered, especially when a patient without a history of pancreatitis presents with pleural effusion.

Pancreatic Neuroendocrine Neoplasm Invading the Entire Main Pancreatic Duct Diagnosed by a Preoperative Endoscopic Biopsy

A 78-year-old man was referred to our hospital for a detailed examination of a pancreatic tumor that filled the main pancreatic duct (MPD). The histological diagnosis of the endoscopic biopsy specimen was neuroendocrine tumor (NET) G3. The patient subsequently underwent total pancreatectomy. The histological diagnosis of the surgical specimen was also NET G3. This is the first report of a NET that occupied the MPD and was diagnosed by a preoperative endoscopic biopsy through the papilla of Vater. This case is a good example of a histopathological diagnostic method for pancreatic tumors invading the entire MPD.

Clinical and Molecular Risk Factors for Recurrence Following Radical Surgery of Well-Differentiated Pancreatic Neuroendocrine Tumors

Well-differentiated pancreatic neuroendocrine tumors are increasingly diagnosed neoplasms. For localized disease, surgery is the first-line therapy and is curative in most cases. However, although recurrence is a rare event, it can still occur up to 10 years from surgery, worsening the prognosis. Many clinical and pathological factors have been associated with recurrence; however, it is currently unclear how to accurately discern patients at risk for relapse of disease from those that should be considered cured. In this review, we focus on clinical, pathological, and molecular factors associated with recurrence and discuss available prediction tools to assess the risk of recurrence following surgery.

Systematic Review and Metaanalysis of Lymph Node Metastases of Resected Pancreatic Neuroendocrine Tumors

BACKGROUND

The optimal surgical strategy for pancreatic neuroendocrine tumors (PNETs) is unknown. However, current guidelines recommend a watch-and-wait strategy for small nonfunctional PNETs (NF-PNETs). The aim of this study is to investigate the risk stratification and prognostic significance of lymph node metastasis (LNM) of PNETs to guide decision-making for lymphadenectomy.

PATIENTS AND METHODS

The MEDLINE and Web of Science databases were systematically searched for studies reporting either risk factors of LNM in resected PNETs or survival of patients with LNM. The weighted average incidence of LNM was calculated according to tumor characteristics. Random-effects metaanalyses were performed, and pooled hazard ratios (HR) and their 95% confidence intervals (CI) were calculated to determine the impact of LNM on overall survival (OS). In subgroup analyses, NF-PNETs were assessed.

RESULTS

From a total of 5883 articles, 98 retrospective studies with 13,374 patients undergoing resection for PNET were included. In all PNETs, the weighted median rates of LNM were 11.5% for small (≤ 2 cm) PNETs and 15.8% for G1 PNETs. In NF-PNETs, the rates were 11.2% for small PNETs and 10.3% for G1 PNETs. LNM of all PNETs (HR 3.87, 95% CI 3.00-4.99, P < 0.001) and NF-PNETs (HR 4.98, 95% CI 2.81-8.83, P < 0.001) was associated with worse OS.

CONCLUSIONS

LNM is potentially prevalent even in small and well-differentiated PNETs and is associated with worse prognosis. A watch-and-wait strategy for small NF-PNETs should be reappraised, and oncologic resection with lymphadenectomy can be considered. Prospective and controlled studies are needed in the future.

Prognostic and predictive factors on overall survival and surgical outcomes in pancreatic neuroendocrine tumors: recent advances and controversies

Introduction: Recent advances in diagnostic modalities and therapeutic agents have raised the importance of prognostic factors in predicting overall survival, as well as predictive factors for surgical outcomes, in tailoring therapeutic strategies of patients with pancreatic neuroendocrine neoplasms (panNENs).Areas covered: Numerous recent studies of panNEN patients report the prognostic values of a number of clinically related factors (clinical, laboratory, imaging, treatment-related factors), pathological factors (histological, classification, grading) and molecular factors on long-term survival. In addition, an increasing number of studies showed the usefulness of various factors, specifically biomarkers and molecular makers, in predicting recurrence and mortality related to surgical treatment. Recent findings (from the last 3 years) in each of these areas, as well as recent controversies, are reviewed.Expert commentary: The clinical importance of prognostic and predictive factors for panNENs is markedly increased for both overall outcome and post resection, as a result of recent advances in all aspects of the diagnosis, management and treatment of panNENs. Despite the proven prognostic utility of routinely used tumor grading/classification and staging systems, further studies are required to establish these novel prognostic factors to support their routine clinical use.

Clinical significance of the preoperative main pancreatic duct dilation and neutrophil-to-lymphocyte ratio in pancreatic neuroendocrine tumors (PNETs) of the head after curative resection

BACKGROUND

The present study aimed to investigate the prognostic significance of preoperative main pancreatic duct dilation and the neutrophil-to-lymphocyte ratio (PD-NLR) in pancreatic neuroendocrine tumors (PNETs) of the head after curative resection.

METHODS

Sixty-four consecutive PNETs of the head that underwent curative resection were included in the study. Preoperative main pancreatic duct dilation (PD) was defined as a pancreatic duct dilation greater than 3 mm before surgery. Patients with both PD and an elevated NLR (> 3.13), with PD or elevated NLR, or neither of these characteristics were allocated a PD-NLR score of 2, 1, or 0, respectively. Univariate, multivariate and Kaplan-Meier analyses were used to calculate overall survival (OS) and disease-free survival (DFS).

RESULTS

Preoperative PD-NLR score was correlated with tumor size (P = 0.005), T-stage (P = 0.016), lymph node metastasis (P <  0.001), distant metastasis (P = 0.005), type of hormone production (P = 0.006), perineural invasion (P = 0.014), and WHO classification (P <  0.001). Patients with a high PD-NLR score had a significantly poor OS and DFS relative to those with a low PD-NLR score (P <  0.001). In the multivariate analysis, PD-NLR score was an independent predictor of OS and DFS for PNET of the head (both P <  0.05). In the analyses of the various subgroups, preoperative PD-NLR score was also a predictor of OS and DFS. Additionally, the survival predictive capability of PD-NLR score was superior to that of WHO classification.

CONCLUSIONS

Despite the retrospective nature and small sample size of the present study, the results suggest that preoperative PD-NLR score can serve as an independent prognostic marker of early survival in patients with PNETs of the head undergoing curative resection. Further large prospective studies are necessary to validate our findings.

Immunohistochemically Detected Expression of ATRX, TSC2, and PTEN Predicts Clinical Outcomes in Patients With Grade 1 and 2 Pancreatic Neuroendocrine Tumors

OBJECTIVE

The goal of this retrospective study was to clarify the clinical implications of immunohistochemically detected protein expression for genes that are frequently mutated in pancreatic neuroendocrine tumors (PNETs).

BACKGROUND

The clinical management of PNETs is hindered by their heterogenous biological behavior. Whole-exome sequencing recently showed that 5 genes (DAXX/ATRX, MEN1, TSC2, and PTEN) are frequently mutated in PNETs. However, the clinical implications of the associated alterations in protein expression remain unclear.

METHODS

We collected Grade 1 and 2 (World Health Organization 2017 Classification) primary PNETs samples from 100 patients who underwent surgical resection. ATRX, DAXX, MEN1, TSC2, and PTEN expression were determined immunohistochemically to clarify their relationships with prognosis and clinicopathological findings.

RESULTS

Kaplan-Meier analysis indicated that loss of TSC2 (n = 58) or PTEN (n = 37) was associated with significantly shorter overall survival, and that loss of TSC2 or ATRX (n = 41) was associated with significantly shorter recurrence-free survival. Additionally, loss of ATRX or TSC2 was significantly associated with nodal metastasis. In a multivariate analysis, combined loss of TSC2 and ATRX (n = 31) was an independent prognostic factor for shorter recurrence-free survival (hazard ratio 10.1, 95% confidence interval 2.1-66.9, P = 0.003) in G2 PNETs.

CONCLUSIONS

Loss of ATRX, TSC2, and PTEN expression might be useful as a method of clarifying the behavior and clinical outcomes of Grade 1 and 2 PNETs in routine clinical practice. Combined loss of TSC2 and ATRX had an especially strong, independent association with shorter recurrence-free survival in patients with G2 PNETs. Loss of pairs in ATRX, TSC2, or PTEN would be useful for selecting the candidate for postoperative adjuvant therapy.

Does attending a Delphi consensus conference impact surgeon attitudes? Survey results from the Americas HepatoPancreatoBiliary Association consensus conference on small asymptomatic pancreatic neuroendocrine tumors

BACKGROUND

Management of asymptomatic small well-differentiated (panNET) <2 cm remains controversial. A consensus conference was held on this topic. The impact of attending the conference and participating in the audience response survey on surgeon's clinical approach to pancreatic neuroendocrine tumors was assessed.

METHODS

Audience members were surveyed using a smartphone real-time response system at the beginning and end of the conference.

RESULTS

The majority of 75 attendees underwent fellowship training, and 30% had >10 years experience as attending surgeons. Previously published consensus statements on the topic were considered insufficient to guide surgical practice by 82% of attendees, and over 96% desired additional data. After review of the data, consensus statements, and decision-making process, a significant number of participants changed their opinions regarding indications for tissue biopsy (p = 0.001), size thresholds for excision (p = 0.002), and regional lymph node dissection (p = 0.002) independent of whether a consensus was reached by the content-expert panel.

CONCLUSIONS

This represented the first Delphi process consensus on the topic, and the survey confirmed the topic as well-chosen and timely. Attendees changed opinions on management of panNET regardless of whether formal consensus was reached. Therefore, statements of consensus combined with presentation of literature and live discussion served to impact attendees' approach to this disease.

Pancreatic neuroendocrine tumors: MR imaging features preoperatively predict lymph node metastasis

PURPOSES

Predictive factors of lymph node metastasis (LNM) in pancreatic neuroendocrine tumors (pNETs) are not well established. We sought to identify the value of MR imaging features in preoperatively predicting the lymph node metastasis of pNETs.

MATERIALS AND METHODS

In this study, we enrolled 108 consecutive patients with pNETs between January 2009 and June 2018. MR morphologic features and quantitative data were evaluated. Predictors of LNM were evaluated using univariate and multivariate logistic regression models.

RESULTS

A total of 108 patients with pNETs were finally enrolled, including 82 LNM-negative and 26 LNM-positive patients. Features significantly related to the LNM of pNETs at univariate analysis were tumor size > 2 cm (P = 0.003), Ki-67 > 5% (P = 0.002), non-enhancement pattern (P < 0.001), apparent diffusion coefficient value (P < 0.001), main pancreatic duct dilation (P < 0.001) and pancreatic atrophy (P = 0.032) and extrapancreatic tumor spread (P = 0.001), CNRs during arterial, portal and delay phase (P = 0.005, 0.047, and 0.045, respectively), and histological classification (P = 0.006). At multivariate analysis, non-enhancement pattern (P = 0.019; odds ratio, 6.652; 95% CI 1.369, 32.321) and main pancreatic duct dilation (P = 0.018; odds ratio, 6.745; 95% CI 1.379, 32.991) were independent risk factors for predicting the LNM of pNETs.

CONCLUSION

The non-enhancement characteristic and main pancreatic duct dilation appear to be linked with LNM in pNETs. These radiological predictors can be easily obtained preoperatively, and may help to avoid missing pNETs with a high risk of LNM.

Imaging of pancreatic neuroendocrine tumors: recent advances, current status, and controversies

INTRODUCTION

Recently, there have been a number of advances in imaging pancreatic neuroendocrine tumors (panNETs), as well as other neuroendocrine tumors (NETs), which have had a profound effect on the management and treatment of these patients, but in some cases are also associated with controversies. Areas covered: These advances are the result of numerous studies attempting to better define the roles of both cross-sectional imaging, endoscopic ultrasound, with or without fine-needle aspiration, and molecular imaging in both sporadic and inherited panNET syndromes; the increased attempt to develop imaging parameters that correlate with tumor classification or have prognostic value; the rapidly increasing use of molecular imaging in these tumors and the attempt to develop imaging parameters that correlate with treatment/outcome results. Each of these areas and the associated controversies are reviewed. Expert commentary: There have been numerous advances in all aspects of the imaging of panNETs, as well as other NETs, in the last few years. The advances are leading to expanded roles of imaging in the management of these patients and the results being seen in panNETs/GI-NETs with these newer techniques are already being used in more common tumors.

Serum Elastase 1 Level as a Risk Factor for Postoperative Recurrence in Patients with Well-Differentiated Pancreatic Neuroendocrine Neoplasms

PURPOSE

This study was designed to assess the potential role of the preoperative serum level of elastase 1 as a risk factor for recurrence in patients with resectable well-differentiated pancreatic neuroendocrine neoplasms (PanNETs).

METHODS

Preoperative serum elastase 1 levels were measured in 53 patients with PanNETs who underwent complete tumor resection in two tertiary referral centers between January 2004 and June 2017. The preoperative elastase 1 levels were correlated with clinicopathological characteristics, including tumor recurrence and recurrence-free survival.

RESULTS

The median elastase 1 level was 96 ng/dL (range: 21-990 ng/dL). Preoperative serum elastase 1 levels were significantly higher in those with tumors ≥ 20 mm in diameter (vs. < 20 mm, P = 0.018), WHO grade 2 (vs. grade 1, P = 0.035), and microscopic venous invasion (vs. without venous invasion, P = 0.039). The median preoperative serum level of elastase 1 was higher in patients with recurrence than in those without recurrence (251 vs. 80 ng/dL, P = 0.004). Receiver operating characteristic analysis of elastase 1 levels showed that a cutoff level of 250 ng/dL was associated with postoperative recurrence, with 63% sensitivity, 100% specificity, and 94% overall accuracy. Patients with higher elastase 1 levels showed significantly worse recurrence-free survival than that of those with lower levels (2-year recurrence-free survival rate: 25% and 92%, respectively, P < 0.001).

CONCLUSIONS

Our data provide the first evidence that high preoperative elastase 1 levels may be a risk factor for postoperative recurrence in patients with resectable PanNETs.

Future Perspectives on Endoscopic Ultrasonography-Guided Therapy for Pancreatic Neoplasm

Endoscopic ultrasonography (EUS)-guided therapy with ethanol injection or catheter-based radiofrequency ablation for pancreatic neoplasm has been conducted as a potential alternate treatment modality for patients who are not eligible for surgery. On the basis of the limited number of studies available, EUS-guided ablation therapy with the aforementioned methods for small pancreatic neoplasms has demonstrated promising technical feasibility and safety profiles. To be considered as a legitimate alternative option to surgery, however, EUS-guided ablation therapy must provide a long-term efficacy profile along with the consensus among experts regarding its treatment parameter. This review focuses on the clinical issues and future perspectives of EUS-guided therapy for pancreatic neoplasm.

Prognosis of sporadic resected small (≤2 cm) nonfunctional pancreatic neuroendocrine tumors - a multi-institutional study

BACKGROUND

Malignant potential of small (≤20 mm) nonfunctional pancreatic neuroendocrine tumors (sNF-PNET) is difficult to predict and management remain controversial. The aim of this study was to assess the prognosis of sporadic nonmetastatic sNF-PNETs.

METHODS

Patients were identified from databases of 16 centers. Outcomes and risk factors for recurrence were identified by uni- and multivariate analyses.

RESULTS

sNF-PNET was resected in 210 patients, and 66% (n = 138) were asymptomatic. Median age was 60 years, median tumor size was 15 mm, parenchyma-sparing surgery was performed in 42%. Postoperative mortality was 0.5% (n = 1), severe morbidity rate was 14.3% (n = 30), and 14 of 132 patients (10.6%) with harvested lymph nodes had metastatic lymph nodes. Tumor size, presence of biliary or pancreatic duct dilatation, and WHO grade 2-3 were independently associated with recurrence. Patients with tumors sized ≤10 mm were disease free at last follow-up. The 1-, 3- and 5-year disease-free survival rates for patients with tumors sized 11-20 mm on preoperative imaging were 95.1%, 91.0%, and 87.3%, respectively.

CONCLUSIONS

In sNF-PNETs, the presence of biliary or pancreatic duct dilatation or WHO grade 2-3 advocate for surgical treatment. In the remaining patients, a wait-and-see policy might be considered.

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.