Diagnosis and molecular aspects of solid-pseudopapillary neoplasms of the pancreas

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.

Cinematic rendering of solid pseudopapillary tumors: Augmenting diagnostics of an increasingly encountered tumor

Pancreatic solid pseudopapillary tumors (SPTs) are a rare subset of pancreatic neoplasms, accounting for under 2 % of exocrine pancreatic tumors. The incidence of SPTs has shown a significant increase in the past two decades, attributed to heightened cross-sectional imaging utilization. These tumors often present with nonspecific clinical symptoms, making imaging a crucial tool in their detection and diagnosis. Cinematic rendering (CR) is an advanced 3D post-processing technique that generates highly photorealistic realistic images by accurately modeling the interaction of light within the imaged volume. This allows improved visualization of anatomic structures which holds potential to improve diagnostics. In this manuscript we present the first description of CR appearances of SPTs in the reported literature. Through showcasing a range of cases, we highlight the potential of CR in illustrating the diverse imaging characteristics of these unique neoplasms.

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.

Frantz Tumor: A Case Report of Solid Pseudopapillary Tumor of Pancreas

The solid pseudopapillary tumor (SPT) is a rare pancreatic lesion that usually affects young and middle-aged patients and has a female predominance and low malignant potential. The exact histogenesis of this tumor is still unclear. We present the case of a 60-year-old female patient with occasional abdominal pain. Positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) revealed a tumor mass in the pancreatic tail. Distal pancreatectomy and splenectomy were performed. The result from the pathology report was solid pseudopapillary neoplasm (SPN). The patient underwent four cycles of adjuvant chemotherapy with gemcitabine, which she tolerated well without complaints. A control computed tomography (CT) scan and PET/CT of the abdomen (five months after the operation) showed a cystic lesion suspicious for local recurrence in the pancreatic tail during the follow-up period. The patient underwent a second surgery operation. Subsequent histological examination showed chronic indurative pancreatitis, areas with steatonecrosis, lipogranulomas, and fibrosis without evidence of relapse. SPT is a rare pancreatic tumor that most commonly affects young women. Although the tumor has locally aggressive characteristics, the prognosis is excellent after surgical excision. Our case emphasizes that this tumor can occur not only in young women but also in older patients. Chronic granulomatous inflammation and indurative pancreatitis can sometimes mimic a relapse on CT and PET/CT image tests.

Role of endoscopic ultrasound in the characterization of solid pseudopapillary neoplasm of the pancreas

BACKGROUND

Solid pseudopapillary neoplasm (SPN) is an uncommon pathology of the pancreas with unpredictable malignant potential. Endoscopic ultrasound (EUS) assessment plays a vital role in lesion characterization and confirmation of the tissue diagnosis. However, there is a paucity of data regarding the imaging assessment of these lesions.

AIM

To determine the characteristic EUS features of SPN and define its role in preoperative assessment.

METHODS

This was an international, multicenter, retrospective, observational study of prospective cohorts from 7 large hepatopancreaticobiliary centers. All cases with postoperative histology of SPN were included in the study. Data collected included clinical, biochemical, histological and EUS characteristics.

RESULTS

One hundred and six patients with the diagnosis of SPN were included. The mean age was 26 years (range 9 to 70 years), with female predominance (89.6%). The most frequent clinical presentation was abdominal pain (80/106; 75.5%). The mean diameter of the lesion was 53.7 mm (range 15 to 130 mm), with the slight predominant location in the head of the pancreas (44/106; 41.5%). The majority of lesions presented with solid imaging features (59/106; 55.7%) although 33.0% (35/106) had mixed solid/cystic characteristics and 11.3% (12/106) had cystic morphology. Calcification was observed in only 4 (3.8%) cases. Main pancreatic duct dilation was uncommon, evident in only 2 cases (1.9%), whilst common bile duct dilation was observed in 5 (11.3%) cases. One patient demonstrated a double duct sign at presentation. Elastography and Doppler evaluation demonstrated inconsistent appearances with no emergence of a predictable pattern. EUS guided biopsy was performed using three different types of needles: Fine needle aspiration (67/106; 63.2%), fine needle biopsy (37/106; 34.9%), and Sonar Trucut (2/106; 1.9%). The diagnosis was conclusive in 103 (97.2%) cases. Ninety-seven patients were treated surgically (91.5%) and the post-surgical SPN diagnosis was confirmed in all cases. During the 2-year follow-up period, no recurrence was observed.

CONCLUSION

SPN presented primarily as a solid lesion on endosonographic assessment. The lesion tended to be located in the head or body of the pancreas. There was no consistent characteristic pattern apparent on either elastography or Doppler assessment. Similarly SPN did not frequently cause stricture of the pancreatic duct or common bile duct. Importantly, we confirmed that EUS-guided biopsy was an efficient and safe diagnostic tool. The needle type used does not appear to have a significant impact on the diagnostic yield. Overall SPN remains a challenging diagnosis based on EUS imaging with no pathognomonic features. EUS guided biopsy remains the gold standard in establishing the diagnosis.

Molecular features of pancreaticobiliary neoplasms: Implications for diagnosis, prognostication, and therapy selection

BACKGROUND

Molecular diagnostics has impacted the diagnosis, prediction of prognosis, and selection of targeted therapy for many tumor types. While pulmonary adenocarcinomas and melanomas are among the neoplasms most associated with molecular diagnostics and targeted therapy, malignancies of the pancreaticobiliary system have also been impacted by precision medicine.

METHODS

We undertook an electronic search using PubMed and Embase to review the published literature to determine what forms of molecular testing, mutations and oncogenetic pathways are associated with neoplasms of the pancreaticobiliary system. Keywords utilized were pancreas, bile duct, mutations, ERCP, FNA, KRAS, SMAD4, TP53, next-generation sequencing, serous cystadenoma, pancreatic ductal adenocarcinoma, intraductal papillary mucinous neoplasm, cystic mucinous neoplasm, solid pseudo-papillary neoplasm.

RESULTS

A search between 1999 and 2022 yielded 6874 manuscripts. Screening of these yielded 302 more focused manuscripts of which 55 were used for the study. Ductal adenocarcinoma of the pancreas is associated with a progression of mutations beginning wit KRAS mutations and ending with a set of mutations in the TP53, SMAD4, and DPC4 genes. Similar mutations are found in neoplastic mucinous cysts. Specific mutations characterize serous cystadenomas, solid, and pseudo papillary neoplasms and adenocarcinomas of the bile ducts.

CONCLUSIONS

Mutational analysis of cytologic specimens obtained by fine-needle aspiration, and duct brushings and washings are helpful in the diagnosis of pancreaticobiliary neoplasms and may supply prognostic information.

Pancreatic Cystic Lesions: A Focused Review on Cyst Clinicopathological Features and Advanced Diagnostics

Macroscopic, endomicroscopic, and histologic findings and correlation are an integral part of the diagnostic evaluation of pancreatic cystic lesions (PCLs), as complementing morphologic features seen by different specialties are combined to contribute to a final diagnosis. However, malignancy risk stratification of PCLs with worrisome features can still be challenging even after endoscopic ultrasound guided-fine needle aspiration (EUS-FNA) with cytological evaluation. This review aims to summarize cyst clinicopathological features from the pathologists' perspective, coupled with knowledge from advanced diagnostics-confocal laser endomicroscopy and cyst fluid molecular analysis, to demonstrate the state-of-art risk stratification of PCLs. This review includes illustrative photos of surgical specimens, endomicroscopic and histologic images, and a summary of cyst fluid molecular markers.

Molecular Alterations in Solid Pseudopapillary Neoplasm of the Pancreas: The Achilles Heel in Conquering Pancreatic Tumorigenesis

Solid pseudopapillary neoplasms of the pancreas are overwhelmingly benign tumors predominately observed in women in the third decade of life. However, their malignant potential, based on local recurrences and metastases, has brought into question the available evidence on their biological behavior. Solid pseudopapillary neoplasms have distanced themselves from other pancreatic tumors with varying morphological appearance, immune profile, and histogenesis. In review of the literature, PubMed was queried using search strings, including "solid pseudopapillary neoplasm" and "molecular," and "immunohistochemistry." Alternative searches were also conducted given the variability in tumor name, including "solid pseudopapillary tumor" and "Frantz tumor." This article provides an in-depth review into the molecular pathways that contribute to the pathogenesis of solid pseudopapillary neoplasms. It also discusses the implications of existing molecular pathways toward tumor aggressiveness and recurrence potential.

Lymphoid Enhancer Binding Factor 1 (LEF1) and Paired Box Gene 8 (PAX8): A Limited Immunohistochemistry Panel to Distinguish Solid Pseudopapillary Neoplasms and Pancreatic Neuroendocrine Tumors

Solid pseudopapillary neoplasms (SPNs) and pancreatic neuroendocrine tumors (PanNETs) are distinctive entities. However, due to overlapping morphologies, distinguishing them remains a diagnostic challenge. Our study investigates the utility of immunohistochemistry for nuclear lymphoid enhancer binding factor 1 (LEF1) and paired box gene 8 (PAX8) in differentiating these 2 entities. LEF1 and PAX8 immunohistochemistry were performed on fine-needle aspiration cell blocks and surgical resection specimens diagnosed as SPN or PanNET at our institution from January 2007 to August 2016. Eight SPN and 25 PanNET cell blocks and 17 SPN and 34 PanNET surgical resection specimens were examined. On cell blocks, positive staining for LEF1 had high frequency, sensitivity, and specificity for SPN (88%, 88%, and 88%) as did positive staining for PAX8 for PanNET (76%, 76%, and 75%). The findings on surgical resection specimens were consistent with those from cell blocks (LEF1+ in SPN: 100%, 100%, and 97%; PAX8+ in PanNET: 59%, 59%, and 100%). A combined LEF1+/PAX8- phenotype showed high sensitivity and specificity for SPN (cell block: 63% and 100%; surgical specimen: 100% and 98%) as did a LEF1-/PAX8+ phenotype for PanNET (cell block: 64% and 100%; surgical specimen: 59% and 100%). SPN and PanNET exhibit opposite immunophenotypic profiles with LEF1+/PAX8- in SPN and LEF1-/PAX8+ in PanNET. The combination of these 2 stains provides an effective means of distinguishing these 2 entities.

[Rare pancreatic tumors]

Beyond pancreatic ductal adenocarcinoma, which is by far the most frequent pancreatic neoplasm, a great variety of tumors occur in the pancreas. They include solid and cystic masses and epithelial and nonepithelial neoplasms, and they show a great diversity in their biological behavior, ranging from benign tumors to highly aggressive neoplasms. As examples of rare pancreatic tumors, clinical, morphological, and molecular aspects of acinar cell carcinoma, pancreatoblastoma, solid pseudopapillary neoplasm, and serous cystic neoplasms are presented and discussed.

Pancreatic Solid Pseudopapillary Neoplasm: Key Pathologic and Genetic Features

CONTEXT.—

Solid pseudopapillary neoplasm of the pancreas is a low-grade malignant tumor generally associated with a good prognosis. Solid pseudopapillary neoplasms show peculiar morphologic features, but sometimes the differential diagnosis with other pancreatic neoplasms (ie, pancreatic neuroendocrine tumors) can be a challenging task, especially in cytologic or biopsy specimens. In these cases immunohistochemistry is a useful tool, but the diagnostic utility of several proposed immunohistochemical markers is questionable. In recent years, despite several attempts to characterize the pathogenetic, molecular, and prognostic features of solid pseudopapillary neoplasms, they still remain unclear.

OBJECTIVE.—

To give the reader a comprehensive update on this entity.

DATA SOURCES.—

The PubMed database (US National Library of Medicine) was searched using the following string: pseudopapillary tumor [AND/OR] neoplasm [AND/OR] pancreas. All articles written in English were included. In addition, because a heterogeneous terminology has been used in the past to define solid pseudopapillary neoplasms, the reference lists of each paper selected in the PubMed database were also reviewed.

CONCLUSIONS.—

This review gives a comprehensive update on the pathologic, clinical, and molecular features of solid pseudopapillary neoplasms, particularly addressing issues and challenges related to diagnosis. In addition, we have tried to correlate the molecular alterations with the morphologic and clinical features.

Large tumor size, lymphovascular invasion, and synchronous metastasis are associated with the recurrence of solid pseudopapillary neoplasms of the pancreas

BACKGROUND

Solid pseudopapillary neoplasms (SPNs) of the pancreas have low malignant potential. However, malignant SPNs are not fully understood.

METHODS

To evaluate risk factors affecting malignant potential, the clinicopathologic features of 375 surgically resected SPNs were compared.

RESULTS

Fifty (13.3%) had malignant histologic features. Twenty-seven and 22 had perineural and lymphovascular invasions, respectively. Adjacent organ invasion was noted in 9 cases. Recurrence occurred in 8 cases. The median recurrence time after surgical resection was 67 months and was associated with a higher pT category (P = 0.001), lymphovascular invasion (P < 0.001), and synchronous metastasis (P < 0.001). SPN patients with malignant histologic features had worse recurrence-free survival (RFS; 10-year survival rate, 73.2%) than those without malignant histologic features (96.3%; P = 0.01). Patients with a higher pT category (P = 0.04), synchronous metastasis (P < 0.01), and lymphovascular invasion (P < 0.01) had worse RFS. Lymphovascular invasion (P = 0.042) and a higher T category (P = 0.002) were poor prognostic factors for recurrence.

CONCLUSION

Lymphovascular invasion and a higher T category were worse prognostic factors for recurrence in SPN patients with malignant histologic features. For SPN patients with malignant histologic features, a longer follow-up may be required.

Clinicopathological and immunohistochemical study of 29 cases of solid-pseudopapillary neoplasms of the pancreas in patients under 20 years of age along with detailed review of literature

Background

Pancreatic Solid Pseudopapillary Neoplasms (SPNs) are rare low-grade malignant tumors with a marked preponderance for young females. Objective was to describe the morphology, differential diagnosis, and prognosis of SPNs in patients under 20 years of age and present a detailed review of literature.

Methods

A total of 29 cases in patients under 20 years of age reported as SPN during the period January 2014 to December 2019, were included in the study. These included 19 resection specimens, 4 incision biopsies and 6 cases received as blocks for second opinion. Hematoxylin and eosin (H&E) slides as well as immunohistochemistry (IHC) slides of all cases were retrieved and reviewed by the authors. TFE3 and Progesterone Receptor were performed retrospectively.

Results

Twenty-eight of the 29 patients were females. Ages of patients ranged from 12 to 19 years. Nineteen cases were resections. Tail was the commonest location. Mean tumor size was 9.5 cm. In 89.5% cases, tumor was confined to the pancreas. In 2 cases, distant metastasis was present. In 2 cases, extension beyond pancreas was seen. Solid and pseudopapillary areas were seen in all cases while other features were variable. Beta catenin and Cyclin D1 were positive in most cases while TFE3 was positive in 57% cases. Progesterone Receptor (PR) was positive in all 13 cases in which it was performed. Follow up was available in 14 patients. Follow up period ranged from 3 to 70 months. Twelve were alive and well without recurrence or metastasis while 2 were alive with recurrence and metastasis to liver and omentum respectively.

Conclusions

Although many studies on SPNs have been published, surgeons, oncologists and even pathologists in this part of the world are often not aware of these rare tumors leading to inaccuracies and delays in diagnosis. In addition, this paper focusses on the interesting observation that the majority of SPNs diagnosed in our department during study period occurred in patients under 20 years of age (29 versus 21 in patients over 20). However, clinico-epidemiological, morphologic and prognostic features were similar in both age groups. Possibility of SPNs should always be considered in case of pancreatic neoplasms occurring in patients under 20 years of age as well. We believe that this is a very interesting and helpful study for the clinicians as well as the pathologists.

Pancreatic solid pseudopapillary neoplasm in male patients: systematic review with three new cases

Pancreatic solid pseudopapillary neoplasm (pSPN) is a rare exocrine neoplasm, which generally occurs in young women. This study analyses the clinical characteristics of pSPN in male patients through a systematic review of the literature, adding three new cases from our institution. We reviewed our experience in Pspns, and we performed a systematic review of pSPN of all articles published in English in PubMed and SCOPUS from 1980. Using the final included articles, we evaluated clinic-pathological features, surgical treatment and prognosis of male patients affected by pSPN. From the literature review and our cases, we collected 246 male patients with a proven pSPN. Mean age was 34.3 (range 4–78) years, with 26.2% patients younger than 18 years. Patients were asymptomatic in 35.9% of cases, despite a mean tumour size of 6.3 cm. In 63.7% of cases, the pSPN was located in the body–tail region. Distant metastases were reported at diagnosis in only 10 (4.1%) patients. A correct pre-operative diagnosis (including cytopathology) was provided in 53.6% of patients, with only 40 fine-needle aspiration/biopsy performed. Standard pancreatic resections represented 90.4% of surgical procedures. Beta-catenin and progesterone receptors were positive at immunostaining in 100% and 77.8% of cases, respectively. Fourteen (7.2%) patients relapsed after a mean disease-free survival of 43.1 months. After a mean follow-up of 47 (range 4–180) months, 89.5% of patients were alive and disease-free. Although rare, when dealing with a solid-cystic pancreatic mass, even in asymptomatic male patients, a pSPN should be considered as a possible diagnosis.

Sclerosing epithelioid mesenchymal neoplasm of the pancreas - a proposed new entity

We have encountered pancreatic tumors with unique histologic features, which do not conform to any of the known tumors of the pancreas or other anatomical sites. We aimed to define their clinicopathologic features and whether they are characterized by recurrent molecular signatures. Eight cases were identified; studied histologically and by immunohistochemistry. Selected cases were also subjected to whole-exome sequencing (WES; n = 4), RNA-sequencing (n = 6), Archer FusionPlex assay (n = 5), methylation profiling using the Illumina MethylationEPIC (850k) array platform (n = 6), and TERT promoter sequencing (n = 5). Six neoplasms occurred in females. The mean age was 43 years (range: 26-75). Five occurred in the head/neck of the pancreas. All patients were treated surgically; none received neoadjuvant/adjuvant therapy. All patients are free of disease after 53 months of median follow-up (range: 8-94). The tumors were well-circumscribed, and the median size was 1.8 cm (range: 1.3-5.8). Microscopically, the unencapsulated tumors had a geographic pattern of epithelioid cell nests alternating with spindle cell fascicles. Some areas showed dense fibrosis, in which enmeshed tumor cells imparted a slit-like pattern. The predominant epithelioid cells had scant cytoplasm and round-oval nuclei with open chromatin. The spindle cells displayed irregular, hyperchromatic nuclei. Mitoses were rare. No lymph node metastases were identified. All tumors were positive for vimentin, CD99 and cytokeratin (patchy), while negative for markers of solid pseudopapillary neoplasm, neuroendocrine, acinar, myogenic/rhabdoid, vascular, melanocytic, or lymphoid differentiation, gastrointestinal stromal tumor as well as MUC4. Whole-exome sequencing revealed no recurrent somatic mutations or amplifications/homozygous deletions in any known oncogenes or tumor suppressor genes. RNA-sequencing and the Archer FusionPlex assay did not detect any recurrent likely pathogenic gene fusions. Single sample gene set enrichment analysis revealed that these tumors display a likely mesenchymal transcriptomic program. Unsupervised analysis (t-SNE) of their methylation profiles against a set of different mesenchymal neoplasms demonstrated a distinct methylation pattern. Here, we describe pancreatic neoplasms with unique morphologic/immunophenotypic features and a distinct methylation pattern, along with a lack of abnormalities in any of key genetic drivers, supporting that these neoplasms represent a novel entity with an indolent clinical course. Given their mesenchymal transcriptomic features, we propose the designation of "sclerosing epithelioid mesenchymal neoplasm" of the pancreas.

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

Solid pseudopapillary neoplasm of the pancreas is a rare tumor of low malignancy that occurs most often in females. The study describes the clinicopathologic characteristics of the tumor and common differential diagnoses. Data were collected from a prospectively maintained database. Of 1661 patients operated for pancreatic tumors between January 2001 and September 2018, 15 patients were recorded. Patients included 12 females and 3 males, median age 40 (range 10 -87) years. Computed tomography or magnetic resonance imaging was diagnostic in eight patients and a preoperative biopsy in eight out of 10 patients. Median tumor size was 5 cm (range 2 -16 cm), 12 tumors were in the head, six in the body, and three in the tail of the gland. All patients except one had radical resection including one with hepatic and lymph node metastases, no patient underwent oncologic treatment. All patients are alive from 17.5 to 209.4 months postoperatively and without recurrence. Radical operation is usually curative and should also be offered to patients with metastases or recurrence as oncologic treatment has limited effect.

Pleomorphic and atypical multinucleated giant cells in solid pseudopapillary neoplasm of pancreas: A diagnostic pitfall in cytology and a review of the literature

Solid pseudopapillary neoplasm of the pancreas (SPN) is a rare low-grade malignancy typically occurring in young women. Occasionally, these neoplasms present with pleomorphic to atypical multinucleated giant tumor cells which may mimic high-grade malignancy. Our patient is a 25-year-old male who presented with one year of intermittent epigastric pain. Magnetic resonance imaging showed a 3.1 × 2.5 cm mass in the pancreas body. Endoscopic ultrasound-guided fine needle aspiration of the mass showed large pleomorphic cells and atypical multinucleated giant cells in a background of singly scattered polygonal cells. Focally, these cells surrounded delicate hyalinized to fibrovascular cores forming pseudopapillae. Immunohistochemical stains show tumor cells are positive for beta-catenin, CD10, vimentin, and CD56. Although rare surgical pathology publications have described the presence of pleomorphic to atypical multinucleated giant cells occurring in SPN, to our knowledge, this is the first case reported example focused on cytomorphologic illustration and description.

Systems Oncology: Bridging Pancreatic and Castrate Resistant Prostate Cancer

Large investments by pharmaceutical companies in the development of new antineoplastic drugs have not been resulting in adequate advances of new therapies. Despite the introduction of new methods, technologies, translational medicine and bioinformatics, the usage of collected knowledge is unsatisfactory. In this paper, using examples of pancreatic ductal adenocarcinoma (PaC) and castrate-resistant prostate cancer (CRPC), we proposed a concept showing that, in order to improve applicability of current knowledge in oncology, the re-clustering of clinical and scientific data is crucial. Such an approach, based on systems oncology, would include bridging of data on biomarkers and pathways between different cancer types. Proposed concept would introduce a new matrix, which enables combining of already approved therapies between cancer types. Paper provides a (a) detailed analysis of similarities in mechanisms of etiology and progression between PaC and CRPC, (b) diabetes as common hallmark of both cancer types and (c) knowledge gaps and directions of future investigations. Proposed horizontal and vertical matrix in cancer profiling has potency to improve current antineoplastic therapy efficacy. Systems biology map using Systems Biology Graphical Notation Language is used for summarizing complex interactions and similarities of mechanisms in biology of PaC and CRPC.

Overexpression of SOX11 and TFE3 in Solid-Pseudopapillary Neoplasms of the Pancreas

OBJECTIVES

To characterize the expression of SOX11 and TFE3 proteins in solid-pseudopapillary neoplasms (SPNs) and their histologic mimickers.

METHODS

Immunohistochemistry for SOX11, TFE3, and β-catenin was performed on 31 cases of surgically resected SPNs. Neuroendocrine tumors, acinar cell carcinomas, and pancreatoblastomas served as controls.

RESULTS

Nuclear immunoreactivity for SOX11 was detected in all SPNs and five of 31 control tumors. Nuclear immunoreactivity for TFE3 was detected in 30 SPNs and three control tumors. Nuclear immunoreactivity for β-catenin was detected in all SPNs and four control tumors. The combination of three markers as immunohistochemical panels resulted in optimal sensitivity and specificity.

CONCLUSIONS

Both SOX11 and TFE3 were overexpressed in SPNs and may be involved in the pathogenesis. Clinically, SOX11 and TFE3 can be potentially used as diagnostic markers in distinguishing indeterminate SPNs from their histologic mimickers.

Differential diagnosis between pancreatic neuroendocrine and solid pseudopapillary neoplasms on endoscopic ultrasound-guided fine-needle aspiration. An immunohistochemical study

Objectives:

To evaluate the role of applying a limited panel of immunohistochemical stains on the cellblock preparation from samples obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in the aim of differentiating solid pseudopapillary neoplasms (SPNs) from neuroendocrine tumors (NETs).

Methods:

We retrospectively retrieved all the EUS-FNAs of the pancreas that have a diagnosis of NET or SPN that were performed at 2 tertiary care hospitals in Riyadh, Kingdom of Saudi Arabia from May 2004 to December 2014. Diff-Quik, Papanicolaou, and Immunohistochemistry stains on cellblock preparations were performed.

Results:

Twenty cases were available (16 pancreatic neuroendocrine tumors (pNETs) and 4 SPNs). The pNETs were immunoreactive for synaptophysin, chromogranin A and CD56 while E-cadherin was diffusely to focally cytoplasmic positive. β-catenin was negative or showed focal cytoplasmic immunoreactivity. In comparison, SPNs were positive for vimentin, CD10, CD-56, focally positive for progesterone receptors and synaptophysin, and revealed nuclear immunostaining for β-catenin. They were negative for chromogranin A and E-cadherin.

Conclusion:

Based on EUS-FNA samples, nuclear immunoreactivity for β-catenin with loss of membranous immunostaining for E-Cadherin can potentially facilitate differentiating SPNs from pNETs.

Solid Pseudopapillary Neoplasm of the Pancreas: A Rare Entity With Unique Features

Solid pseudopapillary neoplasm of the pancreas is a rare entity with low malignant potential and excellent overall prognosis. It has nonspecific clinical presentations such as abdominal pain and nausea, with vague radiologic features. Histologic features of this neoplasm are usually specific. The tumor shows minimally cohesive, uniform, monotonous cells lining delicate capillary-sized blood vessels, described as pseudopapillary architecture. Other features including hyaline globules, cytoplasmic vacuoles, and nuclear grooving are frequently present. Use of a select panel of immunostains always helps pathologists to differentiate this tumor from other circumscribed tumors of the pancreas. Recently, β-catenin, CD10, and E-cadherin have been shown to be very important in the diagnosis of solid pseudopapillary neoplasm. Nuclear staining of tumor cells by β-catenin and membranous presentation of CD10 is seen in almost 100% of cases. Tumor cells can be partially positive for synaptophysin and chromogranin. This tumor has a low malignant potential, and definite treatment is surgical resection.

Somatic Genetic Variation in Solid Pseudopapillary Tumor of the Pancreas by Whole Exome Sequencing

Solid pseudopapillary tumor of the pancreas (SPT) is a rare pancreatic disease with a unique clinical manifestation. Although CTNNB1 gene mutations had been universally reported, genetic variation profiles of SPT are largely unidentified. We conducted whole exome sequencing in nine SPT patients to probe the SPT-specific insertions and deletions (indels) and single nucleotide polymorphisms (SNPs). In total, 54 SNPs and 41 indels of prominent variations were demonstrated through parallel exome sequencing. We detected that CTNNB1 mutations presented throughout all patients studied (100%), and a higher count of SNPs was particularly detected in patients with older age, larger tumor, and metastatic disease. By aggregating 95 detected variation events and viewing the interconnections among each of the genes with variations, CTNNB1 was identified as the core portion in the network, which might collaborate with other events such as variations of USP9X, EP400, HTT, MED12, and PKD1 to regulate tumorigenesis. Pathway analysis showed that the events involved in other cancers had the potential to influence the progression of the SNPs count. Our study revealed an insight into the variation of the gene encoding region underlying solid-pseudopapillary neoplasm tumorigenesis. The detection of these variations might partly reflect the potential molecular mechanism.

Metastatic Renal Cell Carcinoma to the Pancreas: A Review

The pancreas is an unusual site for tumor metastasis, accounting for only 2% to 5% of all malignancies affecting the pancreas. The more common metastases affecting the pancreas include renal cell carcinomas, melanomas, colorectal carcinomas, breast carcinomas, and sarcomas. Although pancreatic involvement by nonrenal malignancies indicates widespread systemic disease, metastatic renal cell carcinoma to the pancreas often represents an isolated event and is thus amenable to surgical resection, which is associated with long-term survival. As such, it is important to accurately diagnose pancreatic involvement by metastatic renal cell carcinoma on histology, especially given that renal cell carcinoma metastasis may manifest more than a decade after its initial presentation and diagnosis. In this review, we discuss the clinicopathologic findings of isolated renal cell carcinoma metastases of the pancreas, with special emphasis on separating metastatic renal cell carcinoma and its various differential diagnoses in the pancreas.

Solid Pseudopapillary Tumor of the Pancreas: One Case with a Metastatic Evolution in a Caucasian Woman

We report the case of a Caucasian woman, operated on for a solid pseudopapillary tumor of the pancreas in 2009, who recurred 4 years later with multiple liver metastases requiring liver resection. This disease is infrequent, particularly among the Caucasian population, and metastatic evolution is very rare.