Differentiation of aggressive from non-aggressive pancreatic solid pseudopapillary neoplasms using computed tomography

Development of a nomogram for predicting the high-risk groups of solid-pseudopapillary neoplasms of the pancreas

Background

Solid pseudopapillary neoplasms (SPNs) of the pancreas are indolent rare tumors with malignant potential. The risk factors associated with the malignant behavior of SPNs are still unclear.

Methods

A retrospective analysis of patients with SPNs who underwent surgical treatment in the First Hospital of Jilin University from January 2010 to January 2022 was conducted. The clinical baseline data, pathology, imaging, and laboratory indicators of the patients were analyzed by univariate and multivariate logistic regression to identify the independent risk factors associated with the high-risk groups, and a predictive model was established in the form of a nomogram.

Results

In multivariate analysis, clinical symptoms (P < 0.001), unclear tumor margins (P = 0.001), incomplete tumor capsules (P = 0.005), maximum tumor diameters ≥ 7.2 cm (P = 0.003), and prognostic nutritional index values < 47.45 (P = 0.007) were independent risk factor for SPNs with high-risk groups. A nomogram model was successfully established to predict high-risk groups of SPNs. The area under the receiver operating characteristic curve was 0.856. The calibration prediction curve was in good agreement with the standard curve.

Conclusion

The nomogram model based on clinical symptoms, inflammatory markers, and imaging features had a high application value in the preoperative prediction of the high-risk groups of SPNs. A novel nomogram of the affiliated hospital of Jilin University-SPNs risk model was proposed for routine application to guide the patient counseling in clinical practice.

Dual-energy CT improves differentiation of non-hypervascular pancreatic neuroendocrine neoplasms from CA 19-9-negative pancreatic ductal adenocarcinomas

PURPOSE

To evaluate the utility of dual-energy CT (DECT) in differentiating non-hypervascular pancreatic neuroendocrine neoplasms (PNENs) from pancreatic ductal adenocarcinomas (PDACs) with negative carbohydrate antigen 19-9 (CA 19-9).

METHODS

This retrospective study included 26 and 39 patients with pathologically confirmed non-hypervascular PNENs and CA 19-9-negative PDACs, respectively, who underwent contrast-enhanced DECT before treatment between June 2019 and December 2021. The clinical, conventional CT qualitative, conventional CT quantitative, and DECT quantitative parameters of the two groups were compared using univariate analysis and selected by least absolute shrinkage and selection operator regression (LASSO) analysis. Multivariate logistic regression analyses were performed to build qualitative, conventional CT quantitative, DECT quantitative, and comprehensive models. The areas under the receiver operating characteristic curve (AUCs) of the models were compared using DeLong's test.

RESULTS

The AUCs of the DECT quantitative (based on normalized iodine concentrations [nICs] in the arterial and portal venous phases: 0.918; 95% confidence interval [CI] 0.852-0.985) and comprehensive (based on tumour location and nICs in the arterial and portal venous phases: 0.966; 95% CI 0.889-0.995) models were higher than those of the qualitative (based on tumour location: 0.782; 95% CI 0.665-0.899) and conventional CT quantitative (based on normalized conventional CT attenuation in the arterial phase: 0.665; 95% CI 0.533-0.797; all P < 0.05) models. The DECT quantitative and comprehensive models had comparable performances (P = 0.076).

CONCLUSIONS

Higher nICs in the arterial and portal venous phases were associated with higher blood supply improving the identification of non-hypervascular PNENs.

Can solid pseudopapillary neoplasm of the pancreas without degeneration be diagnosed with imaging? a comparison study of the solid component of solid pseudopapillary neoplasm, neuroendocrine neoplasm, and ductal adenocarcinoma

PURPOSE

To investigate the MR findings of the solid components within pancreatic solid pseudopapillary neoplasms (SPNs) to characterize solid SPN without degeneration.

METHODS

After case matching, 23 patients with SPNs, 23 with pancreatic neuroendocrine neoplasms (PNENs), and 46 pancreatic ductal adenocarcinomas (PDACs) were included in this retrospective comparative study. The MR findings of the solid components within the pancreatic tumors were assessed qualitatively and semi-quantitatively.

RESULTS

In the qualitative assessment, significant differences were noted in T2-weighted imaging and MR cholangiopancreatography (MRCP). SPNs with a score of 4-5 (iso- to hyper-intense compared with the renal cortex) were observed in 18/19 (94.7%) by reader 1 and 15/19 (78.9%) by reader 2 (score 5, 52.6% and 47.4%) on fast spin-echo (FSE) T2-weighted imaging. On MRCP, the two readers identified 12 (63.2%) and 8 (42.1%) SPNs, respectively. The semi-quantitative signal-intensity ratio (SIR, signal intensity of tumor/signal intensity of the pancreatic parenchyma) of SPNs on FSE T2-weighted imaging was significantly higher (mean, 1.99-2.01) than that of PNENs (1.30-1.31) or PDACs (1.26-1.28). The sensitivity/specificity of 'hyper' on T2-weighted imaging (qualitative score of 4-5, or SIR of ≥ 1.5) were 78.9-100.0%/63.8-79.7%. The sensitivity/specificity of 'remarkably hyper' (score of 5, SIR of ≥ 2.0, or visible on MRCP) or salt-and-pepper pattern were 36.8-68.4%/85.5-98.6%.

CONCLUSION

T2-weighted imaging may be the key sequence for solid SPN. Solid tumors with hyper-intensity on T2-weighted imaging (especially, more hyper-intense than the renal cortex, more than twice the signal of the pancreatic parenchyma, depicted on MRCP, or salt-and-pepper appearance) may be suspected to be SPNs.

Preoperative prediction of invasive behavior of pancreatic solid pseudopapillary neoplasm by MRI-based multiparametric radiomics models

OBJECTIVE

A log-combined model was developed to predict the invasive behavior of pancreatic solid pseudopapillary neoplasm (pSPN) based on clinical and radiomic features extracted from multiparametric magnetic resonance imaging (MRI).

MATERIALS AND METHODS

A total of 111 patients with pathologically confirmed pSPN who underwent preoperative plain and contrast-enhanced MRI were included, and divided into an invasive group (n = 34) and non-invasive group (n = 77). Clinical features and laboratory data related to pSPN invasive behavior were analyzed. Regions of interest were delineated based on T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and contrast-enhanced T1WI (CE-T1WI) to extract radiomic features. Correlation analysis was performed for these features, followed by L1_based feature selection (C = 0.15). A logistic regression algorithm was used to construct models based on each of the four sequences and a log-combined model was used to integrate the sequences. A receiver operating characteristic (ROC) curve was plotted to evaluate the model performance, and the Brier score was used to assess the overall accuracy of the model predictions.

RESULTS

The area under the ROC curve was 0.68, 0.73, 0.71, and 0.49 for Log-T1WI, Log-T2WI, Log-DWI, and Log-CE models, respectively, and 0.81 for the log-combined model. The accuracy, precision, sensitivity, and specificity of the log-combined model were 0.77, 0.88, 0.75, and 0.78, respectively. The best performance was obtained with the log-combined model with a Brier score of 0.18. Tumor location was identified as a significant clinical feature in comparison between the two groups (p < 0.05), and invasive pSPN was more frequent in the tail of the pancreas.

CONCLUSION

The log-combined model based on multiparametric MRI and clinical features can be used as a non-invasive diagnostic tool for preoperative prediction of pSPN invasive behavior and to facilitate the development of individualized treatment strategies and monitoring management plans.

Analysis of invasiveness and tumor-associated macrophages infiltration in solid pseudopapillary tumors of pancreas

BACKGROUND

Solid pseudopapillary tumor (SPT) is a rare pancreatic tumor. Considering its malignant behaviors, SPT has been classified as a low-grade malignant tumor. Indeed, only 9.2% of all SPT patients are initially diagnosed as malignant with invasion or metastasis. Thus, one of the challenges in managing SPT patients is predicting malignant behavior.

AIM

To investigate the malignant behavior and tumor-associated macrophage (TAM) infiltration between different histopathologic features of SPT patients.

METHODS

Twenty-five formalin-fixed paraffin-embedded tissue samples from 22 patients pathologically diagnosed with an SPT between 2009 and 2019 at West China Hospital were included in this retrospective study. Integrity of the capsule and growth pattern of the tumor cells was assessed microscopically in hematoxylin-eosin (HE)-stained sections. Based on the histopathological features, the SPT patients were divided into two groups: capsule or invasion. Clinical features, malignant behavior, and TAM infiltration were compared between the two groups.

RESULTS

Among the 22 SPT patients, 11 were identified for each group, having either a capsule or invasion histopathologic feature. Malignant behavior was more frequent in the invasion group, including 2 patients who had peripheral organ invasion, 3 with liver metastasis, and 1 with both lymph node and spleen metastases (P= 0.045). Ki-67 index of more than 3% was also more frequent in the invasion group (P = 0.045). Immunohistochemical analysis showed that the invasion group had a significant increase of CD68-positive TAMs in intratumor and peritumor sites in comparison with the capsule group (all P < 0.0001). Similarly, CD163-positive M2-like macrophages were also markedly increased in the intratumor and peritumor sites in the invasion group (all P < 0.0001). At the liver metastasis site, both intratumor and peritumor tissues showed relatively high-level CD68-positive TAMs and CD163-positive M2-like macrophages infiltration. However, the differences between the intratumor, peritumor and normal hepatic tissues did not reach statistical significance (all P > 0.05).

CONCLUSION

SPT patients with invasion evident under microscope were more likely to exhibit malignant behavior and TAM infiltration, especially M2-like macrophages. This finding can help in future investigations of the underlying mechanism of TAM-mediated SPT malignant behavior.

The Prognostic Factors of Preoperative Prognostic Nutritional Index and Radiological Findings of Solid Pseudopapillary Tumors of Pancreas: A Single-Center Experience of 14 Years

Introduction

Solid pseudopapillary tumors of pancreas (SPTP) is an indolent rare tumor with malignant potential. The prediction of malignancy is an enigma. The aim of this study is to explore the relationship between operative measurements and malignancy prognosis of SPTP patients.

Methods

A cohort of consecutive 102 patients were enrolled in this study. Preoperative measurements and clinical outcomes were analyzed.

Results

Eighteen patients (17.6%) were confirmed as malignant. The malignant SPTP of the optimal cut-off value was 47.9 (p=0.012) for prognostic nutritional index (PNI). The value of PNI≤47.9 and incomplete capsule were significantly correlated with malignancy. Univariate analysis showed that the PNI≤47.9 (p=0.013) and incomplete capsule (p<0.001) were predictors of disease-specific survival (DSS). Multivariate analysis identified the PNI≤47.9 (p=0.036) and incomplete capsule (p=0.023) as the independent prognostic factors of DSS. The new score of 0,1,2 based on PNI and capsule presence stratified the patients into 3 groups. The patients with low PNI and incomplete capsule achieved the worst prognosis.

Conclusion

The combination test of operative PNI and capsule presence would be a reliable indicator of the aggressive natural history of SPTP.

A Review of Clinicopathological Characteristics and Treatment of Solid Pseudopapillary Tumor of the Pancreas with 2450 Cases in Chinese Population

Background

Solid pseudopapillary tumor of the pancreas (SPTP) has been reported as a rare disease with low malignant potential. The aim of this study was to summarize experiences of the diagnosis and treatment for the patients reported in the Chinese population.

Method

2450 SPTP cases reported in English and Chinese literature before Jan 2020 were for our review and analysis retrospectively.

Result

There are 389 male cases and 2061 female cases, and the ratio of male/female was 1 : 5.3. The average age was 29.3 years. The main clinical symptoms were upper abdominal pain and bloating discomfort in 51.6% of the cases and epigastric mass. 38.6% of the tumor was located at the head of the pancreas and 55.4% at the body and tail of the pancreas. The most frequent operative styles were tumor enucleation (38.4%). Pathology showed that the average diameter of the tumor was 8.2 cm and 12.3% of SPTP was malignant. 98.3% of cases had favorable survival.

Conclusions

SPTP is a rare indolent tumor occurring mainly in young women, and the main clinical performances are abdominal mass and abdominal pain; most tumors are distributed at the head and the tail of the pancreas; the prognosis after complete resection is excellent.