Accuracy of diagnosis of solid pseudopapillary tumor of the pancreas on fine needle aspiration: A multi-institution experience of ten cases

Unraveling the enigma: A comprehensive review of solid pseudopapillary tumor of the pancreas

Solid pseudopapillary tumor of the pancreas (SPTP) is a rare neoplasm predominantly observed in young females. Pathologically, CTNNB1 mutations, β-catenin nuclear accumulation, and subsequent Wnt-signaling pathway activation are the leading molecular features. Accurate preoperative diagnosis often relies on imaging techniques and endoscopic biopsies. Surgical resection remains the mainstay treatment. Risk models, such as the Fudan Prognostic Index, show promise as predictive tools for assessing the prognosis of SPTP. Establishing three types of metachronous liver metastasis can be beneficial in tailoring individualized treatment and follow-up strategies. Despite advancements, challenges persist in understanding its etiology, establishing standardized treatments for unresectable or metastatic diseases, and developing a widely recognized grading system. This comprehensive review aims to elucidate the enigma by consolidating current knowledge on the epidemiology, clinical presentation, pathology, molecular characteristics, diagnostic methods, treatment options, and prognostic factors.

Multicenter Study on the Performance of Imaging Tests Compared to Endosonography-Guided Fine-Needle Aspiration in the Diagnosis of Solid Pseudopapillary Neoplasms of the Pancreas

Introduction

Imaging diagnosis of pancreatic solid-pseudopapillary neoplasms (SPNs) is difficult. Preoperative diagnosis by endosonography-guided fine-needle aspiration (EUS-FNA) is possible and has been reported in the literature in pancreatic tumors. However, its usefulness is still controversial. The aim of this study was to determine the accuracy of the EUS-FNA in the diagnosis of patients with SPN and describe the findings in computerized tomography (CT), magnetic resonance cholangiopancreatography imaging (MRI/MRCP), and EUS therefore comparing the imaging methods alone to the findings of microhistology (McH) obtained by EUS-FNA.

Materials and Methods

We retrospectively reviewed the medical records of patients undergoing EUS-FNA with suspected SPN in imaging studies in 5 Brazilian high-volume hospitals (two university hospitals and three private hospitals). The demographic data; findings in CT, MRI/MRCP, and EUS; and McH results obtained by EUS-FNA were noted prospectively. The final diagnosis was obtained after the anatomopathological examination of the surgical specimen in all patients (gold standard), and we compared the results of CT, MRI/MRCP, EUS, and the McH with the gold standard.

Results

Fifty-four patients were included in the study, of which 49 (90.7%) were women with an average age of 33.4 (range 11-78) years. The most common symptom presented was abdominal pain, present in 35.2% patients. SPN was detected incidentally in 32 (59%) patients. The average size of the tumors was 3.8 cm (SD: 2.26). The most common finding at EUS was a solid, solid/cystic, and cystic lesion in 52.9%, 41.1%, and 7.8% patients, respectively. The final diagnosis was 51 patients with SPN and 3 with nonfunctioning pancreatic neuroendocrine tumors (NF-NET). The correct diagnosis was made by CT, MRI/MRCP, EUS isolated, and EUS-FNA in 21.9%, 28.88%, 64.71%, and 88.24%, respectively. EUS-FNA associated with CT and MRI increased diagnostic performance from 22.72% to 94.11% and from 29.16% to 94.11%, respectively.

Conclusions

SPN are rare, incidentally identified in most cases, and affect young women. Differential diagnosis between SPN, NF-NET, and other types of tumors with imaging tests can be difficult. EUS-FNA increases preoperative diagnosis in case of diagnostic doubt and should be used whenever necessary to rule out NF-NET or other type of solid/cystic nodular lesion of the pancreas.

Endoscopic ultrasound-guided fine-needle aspiration cytology in diagnosing intra-abdominal lesions

Objectives:

Endoscopic ultrasound-guided fine-needle aspiration cytology (EUS-FNAC) is an effective method to acquire tissue from the mucosal, submucosal, and peri-intestinal structure with the pancreas being the most common organ to be targeted. This study is aimed to evaluate the role of EUS-FNAC in pancreatic lesions as well as other gastrointestinal (GI) structures including lymph nodes, upper GI tract, liver, and spleen.

Material and Methods:

A total of 71 cases were taken in which EUS FNAC was performed over 19 months (2018–July 2019). The details analysis of the cytological features was performed in all these cases along with the clinical outcome. The diagnostic efficacy of the EUS-FNAC was evaluated in these cases.

Results:

Out of 71 cases, 36 (50.7%) were male. The most common site being the pancreas 45 (60%) followed by intra-abdominal lymph nodes in 13(17.3%) cases and stomach 7 (9.3%). The neoplastic aspirate was noted in 38 (50.7%) cases. Among malignant lesion, adenocarcinoma was the most common; however, uncommon malignancies such as metastatic malignant melanoma and acinar cell carcinoma were also noted. Malignant lesion in pancreas includes adenocarcinoma (n = 11, 24.4%) followed by neuroendocrine tumor (n = 7, 15.6%). Tuberculosis was one of the common benign lesions to be reported.

Conclusion:

EUS-FNAC is an effective tool in the diagnosis of GI lesion particularly in the pancreas where it can avoid unnecessary surgical intervention in advanced malignancies. It can effectively obtain samples for molecular markers for pancreatic cancers. Nonetheless, diagnosing tuberculosis in inaccessible lymph nodes with its help is a lifesaving approach especially in developing countries.

Solid pseudopapillary neoplasm of the pancreas in a young male with main pancreatic duct dilatation: A case report

BACKGROUND

Solid pseudopapillary neoplasms (SPNs) are rare tumors of the pancreas. Typically, they occur in young females, often have characteristic imaging features, such as cystic components and calcification, and have few effects on the pancreatic duct.

CASE SUMMARY

A 31-year-old man was admitted to our hospital with the chief complaint of epigastric pain. There was only mild tenderness in his upper abdomen, and blood tests showed only a slight increase in alkaline phosphatase. Contrast-enhanced computed tomography showed a 40-mm-diameter, hypovascular mass in the head of the pancreas, and the main pancreatic duct upstream of the mass was severely dilated. Magnetic resonance imaging showed low intensity on T1-weighted images, with high intensity on T2-weighted image in some parts. Pancreatic ductal adenocarcinoma was the primary differential diagnosis. Portal vein infiltration could not be ruled out, so this case was a candidate for neoadjuvant chemotherapy. Subsequently, endoscopic ultrasound-guided fine needle aspiration was performed, and pathological evaluation and immunostaining suggested a diagnosis of SPN. Thus, pancreatoduodenectomy was performed. One year after the operation, the patient is alive with no recurrence.

CONCLUSION

Main pancreatic duct dilatation is usually a finding of suspected pancreatic cancer. However, pancreatic duct dilatation can occur in SPN depending on the location and growth speed. Therefore, SPN should be considered in the differential diagnosis of tumors with pancreatic duct dilatation, and pathological evaluation by endoscopic ultrasound-guided fine needle aspiration should be actively performed.

Clinicopathological Features and Treatment Outcomes of Solid Pseudopapillary Neoplasms of the Pancreas: A 10-Year Case Series from a Single Center

Background: Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare pancreatic tumors. This study summarizes the clinicopathological characteristics and treatment outcomes of SPN patients through a 10-year single-center case series. Materials and Methods: Medical records of patients diagnosed with SPNs and who underwent surgery between August 2007 and July 2017 at Qilu Hospital, Shandong University, were retrospectively analyzed. Results: This study included 91 patients: 13 males/78 females, mean age 28.8 ± 11.5 years. Among the cases, 38.5% were incidentally confirmed without specific symptoms, while the others displayed various abdominal symptoms. All patients had single pancreatic lesions, and 1 patient presented with liver metastasis. Abdominal enhanced computed tomography, magnetic resonance imaging, and endoscopic ultrasound were the diagnostic imaging techniques used to identify SPNs. All patients had successful surgical removal of their tumors; 28 patients underwent laparoscopy. During the 2-121-month follow-up period, 1 patient died of lung metastasis and multiple organ failure at 35 months postoperatively, but no other tumor recurrence or metastasis was found. Conclusions: SPN usually occurs in the young female population and presents with various clinical characteristics. Mixed solid-cystic masses with calcification or hemorrhage are typical morphological tumor features. Minimally invasive organ-/function-preserving operations are advocated for benign cases, while aggressive radical resection should be performed in patients with local invasion or distant metastasis.

Immunocytochemistry for SOX-11 and TFE3 as diagnostic markers for solid pseudopapillary neoplasms of the pancreas in FNA biopsies

BACKGROUND

Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare malignant tumors that can be sampled via endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Although diagnosing SPNs can be straightforward in cases with a classic morphology and a typical immunoprofile, challenges can occur with morphologic variants or limited specimens. Recently, 2 immunohistochemical stains, SRY-related high-mobility group box 11 (SOX-11) and transcription factor E3 (TFE3), have been demonstrated to be highly sensitive and specific for SPNs in pancreatic resection specimens. The current study evaluates the diagnostic utility of these stains with EUS-FNA.

METHODS

Thirteen EUS-FNA specimens from SPNs with sufficient material for immunocytochemistry were identified from 2000 to 2016. These cases were compared with 13 EUS-FNA specimens of non-SPN pancreatic neoplasms. Immunocytochemistry for SOX-11, TFE3, and β-catenin was performed on all cell blocks and then was scored independently by 2 pathologists in a masked manner.

RESULTS

Nuclear reactivity for SOX-11 was detected in 13 of 13 SPNs and in 0 of 13 non-SPNs; this resulted in sensitivity and specificity values of 100%, a positive predictive value (PPV) of 1, and a negative predictive value (NPV) of 1. Nuclear reactivity for TFE3 was detected in 9 of 13 SPNs and in 0 of 13 non-SPNs; this resulted in a sensitivity of 69.2%, a specificity of 100%, a PPV of 1, and an NPV of 0.765. Nuclear reactivity for β-catenin was detected in 13 of 13 SPNs and in 1 of 13 non-SPNs; this resulted in a sensitivity of 100%, a specificity of 92.3%, a PPV of 0.929, and an NPV of 1.

CONCLUSIONS

SOX-11 is a sensitive and specific immunocytochemical stain for SPNs in EUS-FNA specimens, and it may be useful as a diagnostic marker for distinguishing SPNs from its cytologic mimics. Cancer Cytopathol 2017;125:831-7. © 2017 American Cancer Society.

Cytologic criteria to reduce error in EUS-FNA of solid pseudopapillary neoplasms of the pancreas

INTRODUCTION

Standardization of error classification in pathology remains an important issue. This study assesses the extent of error in cytopathologic diagnosis of solid pseudopapillary neoplasms (SPN) of the pancreas. Because of morphologic overlap of SPN and pancreatic neuroendocrine neoplasms (NET), we compared cytologic characteristics to determine which best distinguishes these entities.

MATERIALS AND METHODS

We collected cases diagnosed as SPN either by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) by cytology or surgical pathology from January 2000 to March 2013. An equal number of NET cases were randomly selected. Cytology and surgical pathology cases were evaluated for diagnostic errors and patient impact. Cytologic features in SPN and NET were scored based on presence of previously described characteristics.

RESULTS

A total of 17 patients with EUS-FNA were diagnosed with SPN by cytology or surgical pathology. Of those, 14 had surgical follow-up and 13 had adequate cell blocks and immunohistochemistry. There were 5 discrepancies between cytology and surgical pathology (5 of 14, 36%). There were no false positives or false negatives, but 5 misclassifications: 4 diagnosed as NET on cytology, and 1 as NET versus SPN. All misclassification errors were associated with no harm. When compared with NET, fine chromatin, nuclear grooves, pseud papillae, pink stroma, and hyaline globules are statistically significantly associated with SPN.

CONCLUSIONS

EUS-FNA of pancreatic SPN has excellent positive and negative predictive value, with no false positives or false negatives in this 12-year study. Only misclassification errors as pancreatic NET were made with minimal impact. We suggest that the presence of 3 of 5 major cytologic criteria offer accuracy in diagnosing SPN to prevent misclassification.