Differentiation of solid-pseudopapillary tumors of the pancreas from pancreatic neuroendocrine tumors by using endoscopic ultrasound

doi:10.1016/j.clinre.2020.02.002

Clinics and Research in Hepatology and Gastroenterology

Volume 44, Issue 6, November 2020, Pages 947-953

https://doi.org/10.1016/j.clinre.2020.02.002 Get rights and content

Highlights

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This study compared SPT and pNET systematically and comprehensively.
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SPT tender to have hypovascular sign and cystic components than pNET.
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EUS-FNA is a useful tool that may help clinicians make differential diagnosis.

Summary

Background and aim

To differentiate solid-pseudopapillary tumors (SPTs) of the pancreas from pancreatic neuroendocrine tumors (pNETs) by endoscopic ultrasound.

Methods

We retrospectively reviewed all patients with SPTs and pNETs who underwent endoscopic ultrasound (EUS) from May 2012 to August 2018 at the Fudan University Shanghai Cancer Center. We included patients confirmed pathologically with a surgical biopsy or with endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). The demographic data of the patients, characteristics of the lesions and overall survival data of patients with these two diseases were further compared.

Results

A total of 147 pNET patients and 21 SPT patients were included in our study. The mean ages of the patients in the SPT and pNET groups were 35.95 years and 54.30 years, respectively. There were more females in the SPT group than in the pNET group (71.43% vs. 40.82%). The patients in the pNET group had significantly more lymphatic metastases and visceral organ metastases than the patients in the SPT group. A larger proportion of pNET lesions than SPT lesions had homogeneous echo patterns and were hypervascular. Cystic components and calcification components were more often observed in the SPT lesions than in the pNET lesions. In the multivariate logistic regression analysis, the hypervascularization (OR: 6.528, 95% CI: 1.562–27.285, P = 0.010) and cystic component (OR: 0.106, 95% CI: 0.019–0.597, P = 0.011) variables resulted in the best discrimination of patients with SPTs from patients with pNETs. Survival among patients with SPTs was higher than that among patients with pNETs at all points in the follow-up period.

Conclusions

SPTs tended to occur in younger people and were more common in women. Pancreatic neuroendocrine tumors tended to form metastases more often than SPTs. The blood supply and cystic components of the lesions may have novel potential diagnostic utility for differentiating SPTs from pNETs.

Introduction

Solid-pseudopapillary tumors (SPTs) of the pancreas are a type of rare neoplasm that is typically characterized by a capsule with solid or cystic components inside. The disease is seen mostly in young female patients, and the detection rate of SPTs has increased recently [1]. Pancreatic neuroendocrine tumors (pNETs) are another uncommon pancreatic neoplasm with an increasing incidence; pNETs represent 1.3% of all pancreatic neoplasms. PNETs can present as solid, cystic or mixed (solid-cystic) lesions [2]. Differentiating these two tumors can sometimes be difficult because SPTs and pNETs usually show similar characteristics, such as solid lesions with round shapes and clear borders within the pancreas, and both of these tumors can be solid-cystic lesions. It may be difficult to distinguish between these two diseases with conventional imaging [1], [2]. Endoscopic ultrasound (EUS) is considered the best imaging modality for detecting pancreatic tumors as it has high resolution. EUS is used increasingly for the active surveillance and differential diagnosis of pancreatic tumors, and it has been shown to be significantly better than magnetic resonance imaging (MRI) or computed tomography (CT) in differentiating malignant from benign lesions of the pancreas [3], [4]. With endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), it is even possible to obtain a pathological diagnosis. As SPTs and pNETs are rare diseases, there is a paucity of literature discussing the discrimination of SPTs from pNETs. This study was undertaken to examine the EUS findings of pancreatic SPTs and pNETs to compare the characteristics between the two kinds of pancreatic tumors and to discuss the differences between these two diseases.

Section snippets

Patient selection

This was a retrospective study of data collected from patients with pancreatic occupying lesions who were referred for EUS and operated upon in the Department of Endoscopy at Fudan University Shanghai Cancer Center between May 2012 and August 2018. The inclusion criteria were as follows:

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definitive pancreatic lesions were observed with EUS or other imaging modalities;
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the clinical records and EUS features were available in the electronic database;
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the final diagnosis was confirmed by surgical

Results

The demographic data of the 168 patients are summarized in Table 1. A total of 21 SPT cases and 147 pNET cases were included in our study, and all of the cases were pathologically confirmed. There were 19 SPT cases and 64 pNET cases diagnosed only by surgical pathology, 2 SPT cases and 25 pNET cases were diagnosed with both EUS-FNA and surgical pathology (and the results were consistent), and 58 pNET cases were confirmed only by EUS-FNA. The mean age of the patients in the SPT group was younger

Discussion

Solid-pseudopapillary tumors and neuroendocrine tumors of the pancreas are both rare diseases. Overall, SPTs reportedly account for 1% to 2% of all pancreatic tumors [5], and pNETs account for less than 2% of all pancreatic tumors and 7% of all neuroendocrine tumors [6]. Both of these diseases are usually found incidentally on radiologic examination. The number of patients diagnosed with these two diseases has recently increased with the more widespread use of imaging modalities, including

Disclosure of interest

The authors declare that they have no competing interest.

Acknowledgment

The authors thank all of the staff from the Department of Endoscopy and the Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, for their help in this study.

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Cited by (16)

Bimodal segmentation and classification of endoscopic ultrasonography images for solid pancreatic tumor
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In this paper, we propose a bimodal method based on feature fusion in the neural network, including the endoscopic ultrasonography images and clinical data, for segmentation of solid pancreatic tumors in endoscopic ultrasonography images, and classification of three types of solid pancreatic tumors: pancreatic ductal adenocarcinoma (PDAC), neuroendocrine tumor (pNEN) and solid pseudopapillary tumor (SPN). The database of this study involves 107 cases with 12,809 images. We use Attention U-Net as the backbone with feature fusion layer for segmentation, and a backbone of ResNet50 network with feature fusion layer for classification. The overall dice score, mIOU (segmentation) precision, recall and mIOU (detection) of our best bimodal segmentation model are 0.7552, 0.6241, 0.7204, 0.8003 and 0.6033. The sensitivity, specificity and F1 score of our best bimodal classification model are 0.9903, 1.0000, 0.9951 for PDAC, 0.8348, 0.9470 and 0.8404 for pNEN, 0.8484, 0.9444, 0.8328 for SPN, and an overall accuracy of 0.9180. We also use an interpretation model to analyze the important features that influence the final classification results, and show that clinical data like Carbohydrate antigen 199, Carbohydrate antigen 125, has great influence on the classification of PDAC and pNEN, while SPN depends more on endoscopic ultrasonography image features. Using artificial intelligence to automatically segment solid pancreatic tumors can help medical workers judge their scope and boundaries, and improve the detection rate and efficiency, and the proposed methods for classifying pancreatic masses into 3-class can facilitate physicians to master the clinical and image morphological features of these three pancreatic solid tumors.
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Citation Excerpt :
These three combined features showed acceptable diagnostic performance (AUC = 0.865 with 100% sensitivity and 63.6% specificity); however, the sample size of the study was relatively small, and the prediction model was only reported to be suitable for differentiating SPTs from hypo-vascular NETs. Another study by Liu et al. (20) differentiated SPTs from NETs using EUS in a sample of 147 patients with NETs and 21 patients wiht SPTs whose diagnoses were confirmed pathologically by surgical biopsy or EUS-FNA. They reported that NET lesions were more likely than SPT lesions to show homogeneous echo patterns and to be hyper-vascular.
To evaluate the diagnostic performance of the delayed-phase difference between tumor and pancreas for differentiating solid pseudopapillary tumors (SPTs) from non-functional neuroendocrine tumors (NF-NETs) of the pancreas.
This retrospective review included 148 consecutive patients with SPT and 98 consecutive patients with NF-NET confirmed by pathology. Patients with SPT and NF-NET were matched via propensity score matching (PSM). All patients underwent multidetector computed tomography (MDCT). For each patient, the delayed-phase difference between the tumor and pancreas was measured, and the performance of this variable was assessed based on its discriminative ability and clinical utility.
After PSM, 27 patients with SPT and 27 patients with NF-NET were included in the matched analysis. There were no statistically significant differences in clinical and CT characteristics between the resulting two groups (p > 0.05). The delayed-phase difference values between the tumor and pancreas were significantly lower in patients with SPT (median: -0.45; range: -2.05 to 0.73) than in patients with NF-NET (median: 0.71; range: -1.39 to 2.38). The delayed-phase difference between tumor and pancreas had a high diagnostic accuracy (area under the curve=0.88). The best cutoff point based on maximizing the sum of the sensitivity and specificity was -0.23 (sensitivity = 88.89%; specificity = 88.89%; accuracy = 0.89).
The delayed-phase difference between tumor and pancreas can accurately and noninvasively differentiate SPT from NF-NET.
Differential diagnosis between pancreatic solid pseudopapillary tumors and pancreatic neuroendocrine tumors based on contrast enhanced ultrasound imaging features
2023, Clinical Hemorheology and Microcirculation
The incidence, prevalence, and survival analysis of pancreatic neuroendocrine tumors in the United States
2023, Journal of Endocrinological Investigation
Role of Endoscopic Ultrasound in the Evaluation of Pancreatic Cystic Neoplasms: A Concise Review
2023, Diagnostics
Age in combination with gender is a valuable parameter in differential diagnosis of solid pseudopapillary tumors and pancreatic neuroendocrine neoplasm
2022, BMC Endocrine Disorders

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¹: These authors contributed equally to this work.

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Original articleDifferentiation of solid-pseudopapillary tumors of the pancreas from pancreatic neuroendocrine tumors by using endoscopic ultrasound

Highlights

Summary

Background and aim

Methods

Results

Conclusions

Introduction

Section snippets

Patient selection

Results

Discussion

Disclosure of interest

Acknowledgment

J Med Ultrason

Endocrin Metab Clin North Am

Int J Surg Case Rep

J Am Coll Surg

Curr Probl Surg

Gastrointest Endosc

Diagnostic differentiation of pancreatic neuroendocrine tumor from other neoplastic solid pancreatic lesions during endoscopic ultrasound-guided fine-needle aspiration

Pancreas

B–mode and contrast–enhancement characteristics of small nonincidental neuroendocrine pancreatic tumors

Endosc Ultrasound

Endoscopic ultrasound-guided fine needle aspiration improves the pre-operative diagnostic yield of solid-pseudopapillary neoplasm of the pancreas: an international multicenter case series (with video)

Surg Endosc

Original article
Differentiation of solid-pseudopapillary tumors of the pancreas from pancreatic neuroendocrine tumors by using endoscopic ultrasound