Solid pseudopapillary neoplasm of the pancreas: Clinical-pathological features and management, a single-center experience

Imaging differentiation of solid pseudopapillary neoplasms and neuroendocrine neoplasms of the pancreas

Purpose

The present study aimed to compare the computed tomography (CT) and magnetic resonance imaging (MRI) features of solid pseudopapillary neoplasms (SPNs) and pancreatic neuroendocrine neoplasms (pNENs).

Method

Lesion imaging features of 39 patients with SPNs and 127 patients with pNENs were retrospectively extracted from 104 CT and 91 MRI scans.

Results

Compared to pNEN patients, SPN patients were significantly younger (mean age 51.8 yrs versus 32.7 yrs) and more often female (female: male ratio, 5.50:1 versus 1.19:1). Most SPNs and pNENs presented as well-defined lesions with an expansive growth pattern. SPNs more often appeared as round or ovoid lesions, compared to pNENs which showed a lobulated or irregular shape in more than half of cases (p<0.01). A surrounding capsule was detected in the majority of SPNs, but only in a minority of pNENs (<0.01). Hemorrhage occurred non-significantly more often in SPNs (p=0.09). Signal inhomogeneity in T1-fat-saturated (p<0.01) and T2-weighted imaging (p=0.046) as well as cystic degeneration (p<0.01) were more often observed in SPNs. Hyperenhancement in the arterial and portal-venous phase was more common in pNENs (p<0.01). Enlargement of locoregional lymph nodes (p<0.01) and liver metastases (p=0.03) were observed in some pNEN patients, but not in SPN patients. Multivariate logistic regression identified the presence of a capsule (p<0.01), absence of arterial hyperenhancement (p<0.01), and low patient age (p<0.01), as independent predictors for SPN.

Conclusions

The present study provides three key features for differentiating SPNs from pNENs extracted from a large patient cohort: presence of a capsule, absence of arterial hyperenhancement, and low patient age.

Curative Resection for Metastatic Solid Pseudopapillary Neoplasm of Pancreas-a Case Series

Solid pseudopapillary neoplasm (SPN) is an unusual tumor of the pancreas. Unlike ductal adenocarcinoma, SPN is commoner in young women and is indolent with better prognosis. Fifteen percent of patients, however, develop metastases, often synchronous and involving the liver or peritoneum. Owing to the paucity of cases, management of the metastatic disease is not clearly defined. Retrospective review of case notes of patients treated between 2006 and 2019. There were 53 patients with SPN of which 4 had hepatic metastases-3 synchronous and 1 metachronous. Two patients underwent simultaneous distal pancreatectomy and splenectomy with liver resection (right posterior sectionectomy and metastasectomy). One required right hepatectomy with metastasectomy for metachronous liver metastases. The other underwent a staged operation-remnant tumor excision with metastasectomy followed by right hepatectomy after portal vein embolization. All four patients are recurrence free on median follow-up of 38.5 months. In view of the excellent prognosis, we recommend radical resection of both the primary lesion and metastases for SPN.

Twenty-one years of experience with resected solid pseudopapillary neoplasm: a retrospective single-institutional cohort study

BACKGROUND

Although the incidence of solid pseudopapillary neoplasm (SPN) is <2% of the incidence of pancreatic tumor, the prevalence seems to be increasing. SPNs are mostly benign. However, they also show malignant features. This study aimed to identify the clinical outcomes of patients who underwent surgery for SPN at a single center.

METHODS

Data on 217 patients with SPN who underwent surgery in Samsung Medical Center between 2000 and 2020 were retrospectively analyzed.

RESULTS

Herein, the mean age of the 217 patients was 40.0 ± 12.6 years, with a female predominance (80.6%). Most patients had no comorbidity. The mean tumor size was 4.4 ± 3.1 cm. The tumor was located at the pancreatic head in 36 patients (16.6%), the body of the pancreas in 69 patients (31.8%), and the pancreatic tail in 96 patients (44.2%). Of note, 35 patients (16.1%) underwent pancreaticoduodenectomies, 148 patients (68.2%) had distal pancreatectomies, and the other patients had subtotal /total pancreatectomy (9.7%) or enucleation/mass excision (6.0%). No patient had lymph node (LN) metastasis. Moreover, 6 patients (2.8%) had a recurrence in the liver or regional LNs. The 5-year recurrence-free survival rate was 96.8%. The only factor affecting recurrence was tumor size (P = .007).

CONCLUSION

Because SPN predominates in relatively young women, patients often hesitate to undergo surgery. Nevertheless, as size is the prognostic factor, early resection is recommended for a better prognosis in the case of surgically feasible, young age, and healthy patients.

The diagnosis and management of solid pseudopapillary epithelial neoplasm of the pancreas in a resource-limited setting: two cases from Cameroon

Solid pseudopapillary epithelial neoplasm (SPEN) of the pancreas is a rare tumor of low malignant potential that occurs most often in young females. Imaging and histopathology are necessary to confirm the diagnosis as most have no symptoms. Lack of access to these technologies in sub-Saharan Africa contributes to the difficulty in making an early and accurate diagnosis, and hence, impedes treatment. We present two cases of SPEN of the pancreas in young female patients at a rural, teaching hospital in Cameroon. The diagnosis was made only with histopathology. Computed tomography scan with intravenous contrast was essential to planning a safe surgical resection. Both patients had complete surgical resection with good results.

Solid Pseudopapillary Neoplasm of the Pancreas: A Clinicopathological Study of 12 Cases With Emphasis on Diagnostic Pitfalls

INTRODUCTION

Solid pseudopapillary neoplasm of the pancreas (SPNP) is a rare primary neoplasm with distinct clinicopathological features. The tumor most commonly occurs in younger (premenopausal) women and is typified by low malignant potential and an excellent overall prognosis.

METHODS

A retrospective search over 20 years at two referral tertiary care institutions (King Faisal Hospital and Research Center and King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia) revealed 12 female patients diagnosed with SPNPs. The reslts of ancillary studies performed at the time of diagnosis were also reviewed and placed in the context of current recommendations.

RESULTS

The clinical and pathological findings were reviewed. All patients were females, aged 18 to 30 years. Eight patients presented with abdominal pain, of which two experienced significant weight loss, and four presented with abdominal mass/discomfort. The tumor size ranged from 1.5 and 15 cm. Two cases were initially diagnosed as neuroendocrine tumors (NETs). One of the cases presented as a multifocal disease. All patients were treated surgically with a follow-up period between one and 11 years. Only one patient presented with peritoneal metastasis after seven years of follow-up, but generally, all are doing well.

CONCLUSIONS

We have analyzed 12 SPNP cases in our population over 20 years (2001-2021) in this study. In brief, SPNP is a low-grade malignant potential tumor. Even though SPNP is a recognized entity, diagnostic challenges can arise particularly in the setting of limited sampling. Pathologists must be aware of the classic morphological features of SPNP and the characteristic profile of immunohistochemistry and be able to differentiate SPNP from other mimickers, especially well-differentiated NETs of the pancreas, and ultimately to avoid misdiagnosis and unnecessary oncologic treatment. Adequate surgical resection with negative margins is associated with an excellent outcome.

Pancreatic Cystic Tumors: A Single-Center Observational Study

Background and Objectives: The aim of the study was to analyze the prevalence and characteristics of pancreatic cystic tumors (PCTs). Material and Methods: A retrospective analysis of the medical records of 124 patients, 102 (69%) women and 46 (31%) men, who had undergone surgery for pancreatic cystic tumors in 2014-2018. Among 148 pancreatic cysts, 24 (16%) were non-neoplasmatic and 124 (84%) were neoplasmatic. The neoplasmatic cysts (n = 124) were included in our analysis. There were five main types of PCTs: IPMN (intraductal papillary mucinous neoplasm) (n = 45), MCN (mucinous cystic neoplasm) (n = 30), SCN (serous cystic neoplasm) (n = 28), SPN (solid pseudopapillary neoplasm) (n = 8), and CPEN (cystic pancreatic endocrine neoplasm) (n = 8), as well as mixed-type tumors (n = 5). Results: A statistically significant dependency between PCT type and age was proven (p= 0.0001): IPMNs were observed in the older group of patients with an average age of 66.12 (40-79) years while SPNs were noted in the youngest group of patients with an average age of 36.22 (22-55) years. A statistically significant association between PCT type and gender (p = 0.0001) was found: IPMNs occurred among 24 (53.33%) men and 21 (46.6%) women. In the MCN and SPN groups, all patients were female (100%). Among the SCN group, the majority were women (27 (96.43%)), and there was only 1 (3.57%) man. A statistically significant dependency between PCT type and size was proven (p = 0.0007). The mean size of IPMNs was the smallest 2.95 (0.6-10 cm) and the mean size of MCNs was the largest 6.78 (1.5-19 cm). A statistically significant dependency between PCT type and tumor location was proven (p = 0.000238). The most frequent location of IPMN was the pancreatic head: 27 (60%). MCN was most frequently located in the pancreatic tail (18 (60%)). Most (10/28) SCNs were found in the pancreatic tail (10 (35.71%)). CPENs were most frequently located in the pancreatic tail (three (37.5%)) and pancreatic body and tail (three (37.5%)). SPNs were located commonly in the pancreatic head (five (62.5%)). The type of surgery depended on the tumor location. The most frequent surgery for IPMNs was pancreatoduodenectomy (44.4%), while for MCNs and SCNs, it was distal pancreatectomy (81%). The postoperative morbidity and mortality were 34.68% and 1.61%, respectively. Postoperative pancreatic fistula (POPF) was the most frequent (29%) complication. Conclusions: IPMN was the most frequent resected PCT in our material. A statistically significant association between the type of cyst and location within the pancreas, size, local lymph node involvement, and patient's age and sex was proved. POPF was the most frequent postoperative complication. In patients with PCTs, due to substantial postoperative morbidity, adequate patient selection, considering both the surgical risk as well as the long-term risk of malignant transformation, is very important during qualification for surgery.

Rare Pseudopapillary Neoplasm of the Pancreas: A 10-Year Experience

Introduction

The solid pseudopapillary epithelial neoplasm (SPN) is a rare form of pancreatic neoplasm with an incidence of 2-3% of all pancreatic tumours. The recent increase in incidence is attributed to the increasing use of imaging techniques for nonspecific abdominal complaints. We report our institutional experience in the management of this tumour over the last decade.

Method

We retrospectively analyzed from a prospectively maintained database of patients from January 2011 to December 2020 who were operated upon for SPN. All the patients were followed till date.

Results

Of 479 patients operated on for various types of pancreatic tumours during this period, 15 (3.1%) had SPN. The mean age of presentation was 28 years with a female preponderance (12/15, 80%). The most common location was the body and tail of the pancreas (66%), and the mean size was 6.4 cm (2–15 cm). The tumour extent was defined as ‘borderline resectable' in 20% of cases. Distal pancreatectomy was done in 11 patients with spleen preservation in 3. R0, R1, and R2 resection were done in 12, 2, and 1 patient(s), respectively. The operative mortality was 6.7%. All the patients are doing well on follow-up.

Conclusion

SPN is a low-grade malignant tumour with a strong female predilection. Clinical manifestations have no specificity, imaging examination only contributes tumour location, and the final diagnosis rests on pathology. Surgery is the main modality of treatment and carries a good prognosis.

Computed tomography-based radiomics approach in pancreatic tumors characterization

Radiomics (or texture analysis) is a new imaging analysis technique that allows calculating the distribution of texture features of pixel and voxel values depend on the type of ROI (3D or 2D), their relationships in the image. Depending on the software, up to several thousand texture elements can be obtained. Radiomics opens up wide opportunities for differential diagnosis and prognosis of pancreatic neoplasias. The aim of this review was to highlight the main diagnostic advantages of texture analysis in different pancreatic tumors. The review describes the diagnostic performance of radiomics in different pancreatic tumor types, application methods, and problems. Texture analysis in PDAC is able to predict tumor grade and associates with lymphovascular invasion and postoperative margin status. In pancreatic neuroendocrine tumors, texture features strongly correlate with differentiation grade and allows distinguishing it from the intrapancreatic accessory spleen. In pancreatic cystic lesions, radiomics is able to accurately differentiate MCN from SCN and distinguish clinically insignificant lesions from IPMNs with advanced neoplasia. In conclusion, the use of the CT radiomics approach provides a higher diagnostic performance of CT imaging in pancreatic tumors differentiation and prognosis. Future studies should be carried out to improve accuracy and facilitate radiomics workflow in pancreatic imaging.

MRI-based radiomics approach for differentiation of hypovascular non-functional pancreatic neuroendocrine tumors and solid pseudopapillary neoplasms of the pancreas

BACKGROUND

This study aims to investigate the value of radiomics parameters derived from contrast enhanced (CE) MRI in differentiation of hypovascular non-functional pancreatic neuroendocrine tumors (hypo-NF-pNETs) and solid pseudopapillary neoplasms of the pancreas (SPNs).

METHODS

Fifty-seven SPN patients and twenty-two hypo-NF-pNET patients were enrolled. Radiomics features were extracted from T1WI, arterial, portal and delayed phase of MR images. The enrolled patients were divided into training cohort and validation cohort with the 7:3 ratio. We built four radiomics signatures for the four phases respectively and ROC analysis were used to select the best phase to discriminate SPNs from hypo-NF-pNETs. The chosen radiomics signature and clinical independent risk factors were integrated to construct a clinic-radiomics nomogram.

RESULTS

SPNs occurred in younger age groups than hypo-NF-pNETs (P < 0.0001) and showed a clear preponderance in females (P = 0.0185). Age was a significant independent factor for the differentiation of SPNs and hypo-NF-pNETs revealed by logistic regression analysis. With AUC values above 0.900 in both training and validation cohort (0.978 [95% CI, 0.942-1.000] in the training set, 0.907 [95% CI, 0.765-1.000] in the validation set), the radiomics signature of the arterial phase was picked to build a clinic-radiomics nomogram. The nomogram, composed by age and radiomics signature of the arterial phase, showed sufficient performance for discriminating SPNs and hypo-NF-pNETs with AUC values of 0.965 (95% CI, 0.923-1.000) and 0.920 (95% CI, 0.796-1.000) in the training and validation cohorts, respectively. Delong Test did not demonstrate statistical significance between the AUC of the clinic-radiomics nomogram and radiomics signature of arterial phase.

CONCLUSION

CE-MRI-based radiomics approach demonstrated great potential in the differentiation of hypo-NF-pNETs and SPNs.

Huge solid pseudopapillary tumor of the pancreas 'Frantz tumor': a case report

Solid pseudopapillary neoplasms (SPN) of the pancreas are rare neoplasms accounting for 1-2% of all pancreatic tumors and have a general female predominance. We report a case and intraoperative videos of SPN involving the whole pancreatic tail. A 19-year-old female patient initially presented to another healthcare facility complaining of abdominal pain, which was started 6 years ago. A contrast-enhanced Computed Tomography (CT) scan of the abdomen showed a large mass measuring 15.6 cm × 11.6 cm × 11 cm, arising from the pancreas with an enhancing cystic component. The patient underwent exploratory laparotomy, which revealed a huge mass occupying most of the abdominal cavity. Thus, we proceeded with a distal pancreatectomy and splenectomy. Intraoperatively, the frozen section showed that the mass had features of a solid pseudopapillary tumor of the pancreas with negative resection margins. The SPN diagnosis was confirmed by histopathology and immunohistochemistry. The pathophysiology behind the development of SPN and its cellular origin is still a matter of debate with multiple proposed hypotheses. SPNs are asymptomatic in almost 70% of all cases and usually discovered incidentally. The pre-operative diagnosis of SPNs remains a clinical challenge despite all the current advances in the diagnostic modalities. Surgical management with negative resection margins is the mainstay of treatment, even with metastasis and vascular invasion, surgical excision should be performed whenever feasible. The recurrence rate after surgical resection has been reported to be 3-9%. The prognosis of SPN limited to the pancreas is generally excellent with over 95% cure rate following complete surgical resection. SPN is a rare entity of a controversial origin but is considered as a low-grade malignancy. Surgical resection to achieve complete excision constitutes the mainstay of treatment, which mostly results in an excellent prognosis.