Clinical correlations with (18)FDG PET scan patterns in solid pseudopapillary tumors of the pancreas: still a surgical enigma?

Solid pseudopapillary neoplasm (SPN) of the pancreas: current understanding on its malignant potential and management

Solid pseudopapillary neoplasms (SPN) of the pancreas are presently recognized as low-grade malignant tumors that are frequently observed in young females. This tumor has a low incidence and is associated with an excellent prognosis following surgical resection. Typical SPNs primarily affect the pancreas and tend to have moderate or asymptomatic manifestations. Based on retrospective research, it is anticipated that patients with SPN can achieve disease-free survival, even in cases when metastasis is detected during inspection. However, the incidence of malignant SPN has been consistently underestimated, as evidenced by recent research findings. Malignancy of SPN primarily encompasses invasion and infiltration, metastasis, and recurrence after R0 resection. Imaging technologies such as Ultrasound, Computed Tomography, Magnetic Resonance Imaging, and Position Emission Tomography are capable of preliminarily identifying malignant SPN, which is primarily based on its invasive clinical features. Research on risk factors of malignant SPN revealed that larger tumor size, Ki-67 index, and several other parameters had significant correlations with invasive tumor behavior. Pathologic features of malignant SPNs overlay other pancreatic tumors, nevertheless they can provide valuable assistance in the process of diagnosis. Several confirmed specific pathologic biomarkers are related to its cellular origin, characteristic gene mutation, and cell proliferation. Considering the invasiveness of malignant SPN, it is imperative to enhance the comprehensiveness of its therapy. Tumor resection remains a suggested course of action in line with typical SPN, and additional lymph node dissection is seen as reasonable. Compared to benign SPNs, malignant SPNs have worse prognosis, underscoring the necessity of early identification and treatment in comprehensive medical centers to get improved clinical outcomes.

Clinical Pattern of Preoperative Positron Emission Tomography/Computed Tomography (PET/CT) Can Predict the Aggressive Behavior of Resected Solid Pseudopapillary Neoplasm of the Pancreas

Simple Summary

Predicting the aggressiveness of solid pseudopapillary neoplasms (SPNs) remains a worthwhile goal. The present study aimed to identify perioperative factors that can predict patients who will develop clinically aggressive SPN. A total of 98 patients diagnosed with SPNs were analyzed retrospectively. We found that age (≥40 years; p = 0.039), symptomatic presentation (p = 0.001), tumor size (>10 cm; p < 0.001), positron emission tomography/computed tomography (PET/CT) classification (Type III; p < 0.001), and lymphovascular invasion (p = 0.003) were significantly correlated with aggressive behavior of SPNs. Among these, age ≥40 years, PET/CT Type III configuration, and lymphovascular invasion were independent factors associated with an aggressive SPN. This information can help clinicians develop individualized management and surveillance plans to manage patients more competently.

Abstract

Predicting the aggressiveness of solid pseudopapillary neoplasms (SPNs) remains an important goal. The present study aimed to identify perioperative factors that can predict patients who will develop clinically aggressive SPN. Records of individuals with pathologically confirmed SPN from 2006 to 2017 were obtained from the patient registry database of Yonsei University, Severance Hospital. For this study, aggressive behavior was defined as SPN that had recurred, metastasized, or involved adjacent organs. A total of 98 patients diagnosed with SPNs were analyzed retrospectively. Of these, 10 were reported to have SPNs with aggressive characteristics. We found that age (≥40 years; p = 0.039), symptomatic presentation (p = 0.001), tumor size (>10 cm; p < 0.001), positron emission tomography/computed tomography (PET/CT) classification (p < 0.001), and lymphovascular invasion (p = 0.003) were significantly correlated with aggressive behavior of SPNs. Multivariate analysis showed that PET/CT configuration (p = 0.002) (exp(β)111.353 (95% confidence interval (CI): 5.960–2081), age ≥40 years (p = 0.015) (exp(β) 23.242 (95% CI: 1.854–291.4)), and lymphovascular invasion (p = 0.021) (exp(β) 22.511 (95% CI: 1.595–317.6)) were the only independent factors associated with aggressive SPN. Our data suggest that age ≥40 years, PET/CT Type III configuration, and lymphovascular invasion are independent factors associated with aggressive SPN. This information can help clinicians develop individualized management and surveillance plans to manage patients more effectively.

Pancreatic Schwannoma on FDG PET/CT

A 55-year-old woman underwent FDG PET/CT to evaluate a pancreatic mass. The images showed elevated FDG activity in the uncinated process of the pancreas, suggestive of malignancy. However, pathological examination from the resected lesion demonstrated pancreatic schwannoma.

18F-FDG PET/MR in an Atypical Pediatric Solid Pseudopapillary Pancreatic Tumor

MR and F-FDG PET/MR images of a 15-year-old boy with recurrent mild abdominal pain and hyperamylasemia demonstrating a pancreatic head lesion hypointense on the T1-weighted and slightly hyperintense on the T2-weighted images, with very small pseudocystic areas, restricted diffusion on the apparent diffusion coefficient map, and focal FDG uptake. No other pathologic findings such as enlarged lymph nodes, vascular invasion, metastases, dilatation of the main pancreatic duct, or pathologic uptake of the parotid glands were detected. The MR features, even if atypical, together with the focal uptake, allowed the diagnosis of pediatric solid pseudopapillary pancreatic tumor, which was then confirmed by histology.

Different biological behaviors in left-sided pancreatic cancer according to Yonsei criteria: Proposal of a modified Yonsei criteria score

BACKGROUND/OBJECTIVES

Our institutional experience has demonstrated that bloodless and margin-negative resection is the most potent prognostic factor in treating left-sided pancreatic cancer and we developed selection guideline. The Yonsei criteria (YC) is selection criteria for oncologically safe and effective resection of left-sided pancreatic cancer by a minimally invasive approach. In this study, we investigated whether left-sided pancreatic cancer with YC can be more individualized to predict long-term survival by using clinically and pathologically detectable parameters.

METHODS

From January 2000 to December 2015, 105 patients underwent distal pancreatectomy for left-sided pancreatic cancer. The medical records of the patients were retrospectively reviewed.

RESULTS

Among clinically and pathologically detectable parameters to predict tumor conditions, radiologically determined tumor size (p = 0.080) and SUV_max (p = 0.086) were identified as predictors of early tumor recurrence with marginal significance. Among them, 20% of the patients with YC were identified as having the most favoring tumor condition, with an modified YC score of 3. The patient group with the lowest mYC score was found to have a very long disease-free survival time, with a mean of 108 months, which was statistically different from those with other mYC scores (mYC score = 4, mean 47.1 months [95% CI: 27.8-69.5] vs. mYC score = 5, mean 36.7 months [95% CI: 12.7-60.7], vs. mYC score = 6, mean 10.7 months [95% CI: 3.9-17.4]).

CONCLUSIONS

Modified Yonsei criteria score can predict long-term survival in resected left-sided pancreatic cancer. And patients within YC with a mYC score = 3 could have a favorable survival outcome.

Aggressiveness of solid pseudopapillary neoplasm of the pancreas: A literature review and meta-analysis

BACKGROUND

Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare tumors considered to be benign although 10% to 15% of SPNs have been reported to be aggressive. Due to its rarity, there have only been a few cases reported regarding the clinical course of patients with aggressive SPNs. The goal of this study is to describe the clinical course of patients diagnosed with aggressive SPNs.

METHODS

A PubMed search was done looking for articles describing the clinical course of patients diagnosed with SPN that locally invaded, recurred, or metastasized. Institutional experience was also added to the pooled data. Patient information was extracted from the articles. Survival and recurrence curves were plotted and factors associated with survival and recurrences were analyzed.

RESULTS

A total of 59 patients were identified to have aggressive SPN. Seven patients were males and 52 were females and the mean age was 37.44 ± 2.21 years. Systemic metastasis constituted 81.4% while recurrence and deep tissue invasion were found in 11.9% and 6.8% of the patients, respectively. Disease-free survival was 45 ± 6.28 months and disease-specific survival was 152.67 ± 12.8 months. In survival analysis, age, gender, tumor size, tumor location, combined resection, type of recurrence, and stage IV on diagnosis were not significant factors in predicting survival. However, an unresectable tumor (hazards ratio [HR] = 4.871, 95% confidence interval [CI] 1.480-16.03, P = .009), and metastasis within 36 months (HR = 6.399, 95% CI: 1.390-29.452, P = .017) were identified as independent variables in predicting survival.

CONCLUSION

SPNs of the pancreas carry a favorable course. Despite having aggressive properties, patients can still survive for more than 10 years as long as the tumor can be resected completely.

Prediction of malignancy and adverse outcome of solid pseudopapillary tumor of the pancreas

Since solid pseudopapillary tumor of the pancreas (SPTP) was officially classified by the World Health Organization in 1996, SPTP has recently received special attention in the literature. Studies have shown that SPTP is a heterogeneous tumor, with a small percentage of patients harboring aggressive behaviors. However, criteria for malignancy grade in SPTP have not been well established. The prognosis of SPTP is generally good, with cases having a chance for long-term survival even with recurrence and/or metastasis after surgical resection. The current American Joint Committee on Cancer/Union for International Cancer Control tumor, node, metastasis staging system is not specific to SPTP. The lack of a predictive staging classification that accurately describes the heterogeneity of this disease hinders meaningful research into optimal individualized therapy. Here we summarize and discuss the associated factors proposed for appraisal of the malignant potential and adverse outcome of SPTP.

Metabolic characteristics of solid pseudopapillary neoplasms of the pancreas: their relationships with high intensity 18F-FDG PET images

Objective

We aimed to investigate the metabolic characteristics of Solid pseudopapillary neoplasms (SPNs) in relation signal intensities on ¹⁸F-FDG PET scans.

Summary Background Data

SPNs of the pancreas commonly show high uptake of 18F-FDG. However, the metabolic characteristics underlying the high ¹⁸F-FDG uptake in SPNs are not well characterized.

Materials and Methods

mRNA expressions for glucose metabolism were analyzed in five SPNs, five pancreatic ductal adenocarcinomas (PCAs), and paired normal pancreatic tissues. Among the proteins involved in glucose metabolism, the expressions of five proteins (GLUT1, HK1, PFKM, ENO2, and PKM2) were evaluated in 36 SPNs by immunohistochemistry. Clinical patterns of SPN on PET scans were classified according to the proportion of ¹⁸F-FDG uptake within the whole tumor volume (hot: ≥ 70%, mixed: 30 ≤ < 70, and defective: < 30%). PET-based parameters, including maximum standardized uptake value (SUV_max) and metabolic tumor volume (TMV_2.5), were evaluated.

Results

Hot (n = 19), mixed (n = 5), and defective (n = 12) ¹⁸F-FDG uptake patterns were noted in the 36 patients. Radiologic tumor size and SUV_max differed significantly according to these patterns (ANOVA, p < 0.05). GLUT1, HK1, PFKM, ENO2, and PKM2 were highly expressed in SPNs at both the mRNA and protein levels. Defective type SPNs showed lower expression of HK1 (p = 0.014), PKM2 (p = 0.028), and Ki-67 (p = 0.070) with frequent intra-tumoral necrosis (p = 0.007). High Ki-67 expression (≥ 3%) was associated with high SUV_max in pancreatic SPNs (p = 0.002).

Conclusions

SPN cells harbor an active molecular capacity for increased glucose metabolism. Especially, defective type SPNs were associated with low metabolic activity and related to low Ki-67 index.

Solid pseudopapillary tumor of the pancreas: clinical features and imaging findings

This study aimed to report clinical features and CT, MRI, PET/CT findings of solid pseudopapillary tumor (SPT) of the pancreas. Thirty-four patients with pathologically proven SPT were retrospectively reviewed. Most patients were asymptomatic. SPTs in male patients mainly appeared as solid and near solid tumors. Mixed tumors and cystic tumors had larger size than solid and near solid tumors. Solid tumors and solid part of mixed tumors were T2 hyperintense and T1 hypointense and had progressive enhancement. Four tumors (80%) showed markedly even or uneven ¹⁸F-FDG uptake. These characteristic features can help differentiate SPT from other pancreatic neoplasms.

Clinically determined type of 18F-fluoro-2-deoxyglucose uptake as an alternative prognostic marker in resectable pancreatic cancer

PURPOSE

To investigate the association between clinical PET (positron emission tomography) type and oncologic outcome in resectable pancreatic cancer.

METHODS

Between January 2008 and October 2012, patients who underwent potentially curative resection for resectable pancreatic ductal adenocarcinoma without neoadjuvant treatment were retrospectively investigated. Clinical PET type was defined as follows: pancreatic cancer with similar 18FDG uptake to renal calyx was determined as kidney-type (K-type), and relatively lower 18FDG uptake than that of renal calyx was regarded as Non-K type.

RESULTS

A total of 53 patients were enrolled. After agreement-based reclassification, agreement based K-type (aK-type) was noted in 34 patients (64.2%), and agreement based Non-K type (aNon K-type) was found in 19 patients (35.8%). There was a significant difference between aK-type and aNon K-type pancreatic cancer (tumor size (P = 0.030), adjusted CA 19-9 (P = 0.007), maximum standard uptake value (SUVmax,P<0.001), metabolic tumor volume (MTV2.5, P<0.001), total lesion glycolysis (TLG, P<0.001)). K-type pancreatic cancer (n = 31) showed a significantly shorter disease-free time compared with Non-K type (n = 16) (10.8 vs. 24.1 months, P = 0.013). It was also noted that aK-type showed inferior disease-free survival to that of aNon-K type pancreatic cancer (11.9 vs. 28.6 months, P = 0.012).

CONCLUSIONS

Clinical PET type is a reliable clinical marker to estimate aggressive tumor biology and can be utilized in predicting tumor recurrence and necessity for postoperative chemotherapy.

Solid-Pseudopapillary Tumor of the Pancreas: A Single Center Experience

Aim of this study was to review the institutional experience of solid-pseudopapillary tumors of the pancreas with particular attention to the problems of preoperative diagnosis and treatment. From 1997 to 2013, SPT was diagnosed in 18 patients among 451 pancreatic cystic neoplasms (3.7%). All patients underwent preoperative abdominal ultrasound, computed assisted tomography, and tumor markers (CEA and CA 19-9) determinations. In some instances, magnetic resonance, positron emission tomography, and endoscopic ultrasound with aspiration cytology were performed. There were two males and 16 females. Serum CA 19-9 was slightly elevated in one case. Preoperative diagnosis was neuroendocrine tumor (n = 2), mucinous tumor (n = 2), and SPT (n = 14). Two patients underwent previous operation before referral to our department: one explorative laparotomy and one enucleation of SPT resulting in surgical margins involvement. All patients underwent pancreatic resection associated with portal vein resection (n = 1) or liver metastases (n = 1). One patient died of metastatic disease, 77 months after operation, and 17 are alive and free with a median survival time of 81.5 months (range 36–228 months). Most of SPT can be diagnosed by CT or MRI, and the role of other diagnostic tools is very limited. We lack sufficient information regarding clinicopathologic features predicting prognosis. Caution is needed when performing limited resection, and long and careful follow-up is required for all patients after surgery.

Maximum Standard Uptake Value as a Clinical Biomarker for Detecting Loss of SMAD4 Expression and Early Systemic Tumor Recurrence in Resected Left-Sided Pancreatic Cancer

This study investigated the oncologic impact of loss of SMAD4 expression in resected left-sided pancreatic cancer and its correlation with tumor metabolism.From 2005 to 2011, the medical records of patients who underwent radical distal pancreatectomy for resectable pancreatic cancer were retrospectively reviewed. Formalin-fixed, paraffin embedded tissue from 32 patients was investigated. Clinicopathological characteristics, immunostaining of SMAD4, and positron emission tomography-based parameters were analyzed in relation to oncologic outcomes.Thirteen patients were women and 19 were men, with a mean age of 63 ± 9.4 years. Mean resected tumor size was 3.3 ± 1.5 cm. Ten patients (31.3%) showed loss of SMAD4 expression. No significant clinicopathological differences were noted according to SMAD4 expression (P > 0.05); however, patients with loss of SMAD4 showed significantly poorer disease-free survival (mean 57.4 months vs mean 17.6 months, P = 0.006). As a cut-off value, a SUVmax of 4.5 was found to be predictive of loss of SMAD4 with a sensitivity of 75% and a specificity of 84.6%. In logistic regression analysis, SUVmax>4.5 was found to infer a 16-fold higher risk for loss of SMAD4 in resected left-sided pancreatic cancers (Exp[β] = 16.5, P = 0.012, 95% confidence interval: 1.832-148.606).Loss of SMAD4 is associated with poor oncologic outcomes. SUVmax can predict loss of SMAD4 in resected left-sided pancreatic cancer. SUVmax may be a clinical biomarker for detecting loss of SMAD4 expression and predicting early systemic metastasis.

Solid cystic pseudopapillary tumor of pancreas with splenic metastasis: Case report and review of literature

INTRODUCTION

Solid-cystic pseudopapillary tumor of the pancreas is rare and most commonly seen in young women. We present a young women with solid-cystic pseudopapillary tumor of the pancreas and discuss the literature.

PRESENTATION OF CASE

Thirty nine years old female patient with a mass about 12cm in the pancreas with splenic invasion seen in our clinic. After having CT and PET-CT view, patient underwent surgery. Distal pancreatectomy with mass excision and splenectomy was performed. Microscopic examination result was solid cystic pseudopapillary tumor with spleen invasion.

DISCUSSION

Solid-cystic pseudopapillary tumor of the pancreas has cystic solid pseudopapillary structures. Prognosis of tumor is better than other pancreatic tumor. Complete resection of tumor with splenic inclusion is surgical treatment.

CONCLUSION

In case of large slow growing pancreatic tumor with splenic metastasis, solid-cystic pseudopapillary tumor of the pancreas should be considered in the diagnosis. Complete surgical resection is associated with long-term survival even in the presence of metastatic disease. Close follow-up is necessary after surgery.