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, ß-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.

Solid Pseudopapillary Tumor of the Pancreas: Is Enucleation Safe?

BACKGROUND: While solid pseudopapillary tumor (SPT) of the pancreas are oncologically low-risk tumors, their resection with pancreaticoduodenectomy (PD) or partial pancreatectomy (PP) carries a significant risk for morbidity. To balance the favorable prognosis with the surgical morbidity of pancreas resection, this study explores the oncologic safety of enucleation (EN). PATIENTS AND METHODS: The National Cancer Database (NCDB) was queried for resected SPT from January 2004 through December 2020. Perioperative outcomes and survival were analyzed with Kruskal-Wallis tests, and Kaplan-Meier analysis (with log-rank test). Survival analysis was performed to compare patients with and without lymph node (LN) metastases and binary logistic regression for predictors of LN metastasis. RESULTS: A total of 922 patients met inclusion criteria; 18 patients (2%) underwent EN, 550 (59.6%) underwent PP, and 354 (38.4%) underwent PD. Mean tumor size was 57.6 mm. Length of hospital stay was significantly shorter for EN compared with PP and PD groups (3.8 versus 6.2 versus 9.4 days, p < 0.001). There was a nonsignificant improvement in unplanned readmission [0% versus 8% versus 10.7% (p = 0.163)], 30-day mortality [0% versus 0.5% versus 0% (p = 0.359)], and 90-day mortality [0% versus 0.5% versus 0% (p = 0.363)] between EN, PP, and PD groups. Survival analyses showed no difference in OS when comparing EN versus PP (p = 0.443), and EN versus PD (p = 0317). Patients with LN metastases (p < 0.001) fared worse, and lymphovascular invasion, higher T category (T3-4) and M1 status were found as predictors for LN metastasis. CONCLUSIONS: EN may be considered for select patients leading to favorable outcomes. Because survival was worse in the rare cohort of patients with LN metastases, the predictors for LN metastasis identified here may aid in stratifying patients to EN versus resection.

[18F]FDOPA PET/CT in Solid Pseudopapillary Tumor of the Pancreas: a Recurred Tumor Mimicking Splenosis.

Solid pseudopapillary tumor (SPT) of the pancreas is a neoplasm with low malignant potential. It is often challenging to diagnose SPT due to its nonspecific clinical and radiological features, and [18F]FDOPA is effective in diagnosing SPT, particularly in differentiating SPT from benign conditions such as splenosis. A 55-year-old woman underwent distal pancreatectomy and splenectomy for histologically confirmed SPT. She was also initially diagnosed with splenosis. During follow-up, sizes of multiple nodular lesions were increased, raising the possibility of peritoneal seeding of SPT. For diagnosis, a spleen scan and SPECT/CT were performed using 99mTc-labeled damaged red blood cells, which showed no uptake in the peritoneal nodules. Subsequent [18F]FDOPA PET/CT revealed [18F]FDOPA-avidity of the nodules. The patient underwent tumor resection surgery, and the nodules were pathologically confirmed as SPT.

CT target scanning in the diagnosis of solid pseudopapillary tumor of the pancreas.

OBJECTIVE: To discuss the value of computed tomography (CT) iterative reconstruction technique combined with target scanning in the diagnosis of solid pseudopapillary tumor of the pancreas (SPTP). METHODS: The clinical information and CT examination data of 27 patients with SPTP were retrospectively analyzed, and the general condition and CT performance of the patients were observed. The CT image reconstruction algorithm of all patients used iterative reconstruction technique combined with the application of target scanning technique. RESULTS: A total of 27 patients were included in this study, including 6 males and 21 females, aged 14-72 years with a mean age of 39.6 ± 13.6 years. SPTP was more common in young and middle-aged females, with a low level of tumor markers, dominated by cystic-solid tumors. The combination of CT iterative reconstruction technology and targeted scanning revealed the following: the capsule of SPTP was clear and complete, where calcifications were visible, solid components were progressively enhanced, and rare pancreatic and bile duct dilation was seen. Tumors were cystic-solid in 18 of 27 patients with SPTP, of which the solid components showed isodensity or slightly low-density, with calcifications. The solid components and cyst walls were mildly enhanced during the arterial phase, and were progressively enhanced during the parenchymal phase, portal vein phase, and delayed phase, with their enhancement degree lower than that of normal pancreatic parenchyma, and pancreatic and bile duct dilation was rare. There were no statistical differences in tumor location, morphology, growth pattern, integrity of capsule, cystic or solid, calcifications, and enhancement features between the male group and the female group (P > 0.05). CONCLUSION: The iterative reconstruction combined with target scanning clearly displayed the CT features of tumors, helping the diagnosis and clinical treatment of the disease.

Retroperitoneal Solid Pseudopapillary Tumor Mimicking Adrenal Malignant Tumor in a 67-Year-Old Man.

Solid pseudopapillary tumor (SPT) is a low-grade malignant tumor of the pancreas. SPT typically affects women and can occur in ectopic pancreatic region; however, it also occurs rarely in retroperitoneum. The tumor may be bulky at the time of diagnosis since there is no specific clinical manifestation. Here we present an older male case with retroperitoneal SPT. A 67-year-old man consulted for intermittent fever and lumbago. His basal hormonal profile screened out a functional tumor. Computed tomography (CT) showed a gigantic mass in his left adrenal region. A normal left adrenal gland was not identified, and the tumor's feeding artery was recognized as the left adrenal artery by the contrast-enhanced CT. Adrenal malignant tumor was suspected, and tumor resection was performed. The resected tumor size was 15 × 10 × 9 cm. Histologically, epithelial-like cells with round nuclei and a small amount of eosinophilic cytoplasm proliferated in papillary (around the blood vessels) or uniformly solid form. By immunostaining, tumor cells were vimentin, CD56, cytokeratin AE1/AE3, CD10, ß-catenin in the nucleus, cyclin D1, and PgR positive. These findings led to the diagnosis of SPT. Although rare, SPT should be considered as a differential diagnosis in cases of a mass arising from the adrenal region.

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.

Introdução: O diagnóstico por imagem da neoplasia pseudopapilar sólida do pâncreas (NPS) é difícil. O diagnóstico pré-operatório obtido pela endosonografia com punção aspirativa por agulha fina (USE-PAF) é possível e tem sido relatado na literatura em tumores do pâncreas. No entanto, sua indicação é controversa e merece discussão. O objetivo do estudo foi determinar a acurácia da USE-PAF no diagnóstico de pacientes com NPS, descrever os achados da tomografia computadorizada (TC), colangiopancreatografia por ressonância magnética (RM/ CPRM) e USE, comparando os métodos de imagem isolados aos achados da microhistologia (McH) obtida pela USE-PAF. Material e Métodos: Revisamos retrospectivamente os prontuários de pacientes submetidos à USE-PAF com suspeita de NPS em exames de imagem de 5 hospitais brasileiros de alto volume (dois universitários e três privados). Foram anotados prospectivamente os dados demográficos, os achados da TC, RM/CPRM e USE e o resultado da McH obtida pela USE-PAF. O diagnóstico final foi obtido após o anatomopatológico da peça operatória em todos os pacientes (padrão-ouro). Comparamos os resultados da TC, RM/CPRM, EUS isoladas e da McH obtida pela USE-PAF com o padrão-ouro. Resultados: Cinquenta e quatro pacientes foram incluídos no estudo, 49 (90.7%) eram mulheres com média de idade de 33.4 (11­78) anos. O sintoma mais frequente foi dor abdominal, presente em 35.2%. A NPS foi detectada acidentalmente em 32 (59%) pacientes. O tamanho médio da lesão foi de 3.8 cm (SD: 2.26). O achado mais comum à USE foi lesão sólida, sólida/ cística e cística em 52.9%, 41.1% e 7.8%, respectivamente. O diagnóstico final foi NPS (51) e tumor neuroendócrino pancreático não funcionante [NF-NET] (3). O diagnóstico correto feito pela TC, RM, USE e USE-PAF foi feito em 21.9%, 28.9%, 64.7% e 88.2%, respectivamente. A USEPAF associada a TC e a RM aumentou o desempenho diagnóstico de 21.9% para 94.1% e de 28.8% para 94.1%, respectivamente. Conclusões: NPS são raras, identificadas de forma acidental na maioria dos casos e afetam principalmente mulheres jovens. O diagnóstico diferencial entre NPS, NF-NET e outros tipos de lesões com exames de imagem isolados pode ser difícil. A USE-PAF aumenta a chance do diagnóstico pré-operatório em caso de dúvida diagnóstica e deve ser usado sempre que necessário para descartar NF-NET ou outro tipo de lesão nodular sólida ou sólido/cística do pâncreas.

A Case of Solid Pseudopapillary Tumor of the Pancreas.

We report a rare case of solid pseudopapillary neoplasm in a 24-year-old woman, who presented with progressively worsening left epigastric and right lower quadrant abdominal pain for several weeks. A CT scan showed a mass in the tail of the pancreas that extended to the hilum of the spleen. Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) and immunohistochemical analysis exhibited findings pathognomonic for solid pseudopapillary neoplasm. The patient underwent distal pancreatectomy and splenectomy. Post-surgical biopsy confirmed the FNA findings, with the tumor confined to the pancreas and no extension to nearby structures. The patient did not require any other adjuvant therapy. She was asymptomatic at the one-month follow-up and showed no signs of disease. We discuss the unique circumstances of this case and highlight the importance of differentiating this tumor from other pancreatic neoplasms.

Frantz's Tumor in Focus: The Tale of a 34-Year-Old Yemeni Female Patient.

A solid pseudopapillary tumor (SPT) of the pancreas, which mainly occurs in young women, is an uncommon pancreatic tumor that often presents diagnostic and therapeutic dilemmas. This case study discusses the symptoms and treatment approach for a 34-year-old woman from Yemen diagnosed with SPT. The patient was diagnosed through abdominal and pelvis CT scan, followed by ultrasound-guided biopsy confirming the presence of SPPT. Management through the Whipple procedure and portal vein reconstruction proved successful, with no recurrence or metastasis noted in a year-long follow-up. The importance of comprehensive understanding and surgical expertise in handling SPT is emphasized.

Differential diagnosis between pancreatic solid pseudopapillary tumors and pancreatic neuroendocrine tumors based on contrast enhanced ultrasound imaging features.

PURPOSES: To evaluate the application of contrast enhanced ultrasound (CEUS) in preoperatively differential diagnosis between pancreatic solid pseudopapillary tumors (SPTs) and pancreatic neuroendocrine tumors (pNETs). PATIENTS AND METHODS: This retrospective study was approved by Institutional Review Board. Patients with surgical resection and histopathological diagnosis as SPTs and pNETs were included. All patients underwent B mode ultrasound (BMUS) and CEUS examinations within one week before surgical operation. On BMUS, the size, location, echogenicity, calcification, and margin of lesions were observed and recorded. On CEUS imaging, enhancement patterns, and enhancement degrees were recorded and analyzed. An independent t-test or Mann-Whitney U test was used for comparison between continuous variables. Chi-square test was used to compare the CEUS patterns. RESULTS: From February 2017 to Dec 2022, patients diagnosed as SPTs (n = 39) and pNETs (n = 48) were retrospectively included. On BMUS, anechoic cystic changes (19/39, 48.72%) and hyperechoic calcification (14/39, 35.90%) are more commonly detected in SPTs (P = 0.000). On CEUS imaging, the majority of SPTs (27/39, 69.23%) showed hypo-enhancement in the arterial phase, while most of the pNETs (36/48, 75.00%) showed hyper- or iso-enhancement in the arterial phase (P = 0.000). In the venous phase, most of the SPTs (32/39, 82.05%) showed hypo-enhancement, while over half of pNETs (29/48, 60.42%) showed hyper- or iso-enhancement compared to pancreatic parenchyma (P = 0.001). CONCLUSIONS: CEUS is a valuable and non-invasive imaging method to make preoperatively differential diagnoses between SPTs and pNETs.

Tumor Sólido Pseudopapilar de Páncreas en varón

Objetivo: Comunicar el caso de un varón diagnosticado de tumor sólido pseudopapilar de páncreas (TSPP). Esta patología afecta fundamentalmente a mujeres jóvenes, siendo extremadamente infrecuente en hombres. Caso Clínico: Varón de 40 años diagnosticado por TC de masa intraabdominal sólida bien delimitada, de 12,5 × 13 × 8,5 cm, heterogénea, con calcificaciones periféricas y realce tras la administración de contraste en fase portal, dependiente de cuerpo-cola pancreática. Se realiza puncion, no concluyente. La laparotomía exploradora mostró tumoración sólida dependiente de cola pancreática que incluye vasos esplénicos. Se liberó el tumor de forma periférica, requiriendo pancreatectomía distal y esplenectomía. El resultado AP informó neoplasia pseudopapilar sólida de cola pancreática de bajo grado de malignidad, bien diferenciado (G1). Alta hospitalaria al 12° día sin complicaciones. Actualmente libre de enfermedad tras dos años de la intervención. Discusión: Este tumor infrecuente representa el 1%-3% de las neoplasias pancreáticas. El 90% afecta a mujeres jóvenes, con proporción de mujeres a hombres de 4:1. En estos, tiene mayor potencial maligno con peor pronóstico. Conclusión: La baja incidencia en varones puede dificultar el diagnóstico. Sin embargo, debemos tenerlo en cuenta en el diagnóstico diferencial, ya que el tratamiento quirúrgico radical aumenta significativamente la supervivencia al evitar la recurrencia local y las metástasis a distancia, lo que supone un reto quirúrgico.

Objective: To report the case of a male diagnosed with a solid pseudopapillary tumor of the páncreas. This pathology fundamentally affects young women, being extremely infrequent in men. Clinical Case: A 40-year-old man diagnosed by CT with a well-defined solid intra-abdominal mass, 12.5 × 13 × 8.5 cm, heterogeneous, with peripheral calcifications and enhancement after contrast administration in the portal phase, dependent on the body-tail of the pancreas. Fine needle puncture is performed, inconclusive. The exploratory laparotomy showed a solid tumor dependent on the pancreatic tail that included splenic vessels. The tumor was released peripherally, requiring distal pancreatectomy and splenectomy. The AP result reported solid pseudopapillary neoplasm of the pancreatic tail of low grade of malignancy, well differentiated (G1). Hospital discharge on the 12th day without complications. Currently free of disease two years after the intervention. Discussion: This rare tumor represents 2%-3% of pancreatic neoplasms. 90% affects young women, with a ratio of women to men of 4:1. In these, it has greater malignant potential with worse prognosis. Conclusion: The low incidence in males can make diagnosis difficult. However, we must take it into account in the differential diagnosis, since radical surgical treatment significantly increases survival by avoiding local recurrence and distant metastases, which is a surgical challenge.

A rare pancreatic neoplasm in a 40-year-old male patient.

Key Clinical Message: The differential diagnoses of solid pseudopapillary neoplasm of the pancreas include cystic pancreatic neuroendocrine tumor, acinar cell carcinoma, and pancreatoblastoma. Abstract: Solid pseudopapillary neoplasm (SPN) is a low-grade malignant pancreatic tumor which accounts for 0.9%-2.7% of all exocrine pancreatic neoplasms. It predominantly affects young females (90%) and less frequently occurs in male patients. Its prognosis after surgical resection remains excellent. Herein, we report a case of SPN in a male patient.

Solid pseudopapillary tumor of the pancreas: A systematic review of clinical, surgical and oncological characteristics of 1384 patients underwent pancreatic surgery.

BACKGROUND: Pancreatic solid pseudopapillary tumors (SPTs) are rare clinical entity, with low malignancy and still unclear pathogenesis. They account for less than 2% of exocrine pancreatic neoplasms. This study aimed to perform a systematic review of the main clinical, surgical and oncological characteristics of pancreatic SPTs. DATA SOURCES: MEDLINE/PubMed, Web of Science and Scopus databases were systematically searched for the main clinical, surgical and oncological characteristics of pancreatic SPTs up to April 2021, in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) standards. Primary endpoints were to analyze treatments and oncological outcomes. RESULTS: A total of 823 studies were recorded, 86 studies underwent full-text reviews and 28 met inclusion criteria. Overall, 1384 patients underwent pancreatic surgery. Mean age was 30 years and 1181 patients (85.3%) were female. The most common clinical presentation was non-specific abdominal pain (52.6% of cases). Mean overall survival was 98.1%. Mean recurrence rate was 2.8%. Mean follow-up was 4.2 years. CONCLUSIONS: Pancreatic SPTs are rare, and predominantly affect young women with unclear pathogenesis. Radical resection is the gold standard of treatment achieving good oncological impact and a favorable prognosis in a yearly life-long follow-up.

Neoplasia pseudopapilar sólida del páncreas (tumor de Frantz) en una joven de 13 años / Solid pseudopapillary tumor of the pancreas (Frantz tumor) in a 13-year-old girl

RESUMEN El tumor sólido pseudopapilar de páncreas (TSP) es un tumor infrecuente, de bajo grado de malignidad, que representa el 1-3% de todas las neoplasias pancreáticas, con predilección por el sexo femenino, y es el tumor sólido de páncreas más frecuente en la infancia. Mujer de 13 años que consultó por dolor abdominal de 5 días de evolución, en hipocondrio derecho e irradiado a espalda, con náuseas y vómitos. TSP es diagnosticado con ecografía, tomografía computarizada (TC) y resonancia magnética (RM). Se realizó duodenopancreatectomía cefálica. La paciente fue dada de alta. El examen anatomopatológico informó un TSP de páncreas. El abordaje quirúrgico de estos tumores, abierto o laparoscópico, permite una excelente supervivencia alejada.

ABSTRACT Solid pseudopapillary tumor (SPT) of the pancreas is a rare neoplasm with a low malignant potential and represents 1- 3% of all pancreatic tumors. They usually occur in women and are the most common solid pancreatic tumor in children. A 13-year-old girl visited the emergency department due to abdominal pain in the right hypochondrium radiating to the back, nausea and vomiting lasting 5 days. A SPT was diagnosed by ultrasound, computed tomography (CT) scan and magnetic resonance imaging (MRI). The patient underwent cephalic pancreaticoduodenectomy and was discharged. The pathological study reported a SPT of the pancreas. The surgical approach of these tumors through open surgery or laparoscopy offers excellent long-term survival.

Efficacy and predictive factors of endoscopic ultrasound-guided ethanol ablation in benign solid pancreatic tumors.

BACKGROUNDS AND OBJECTIVES: Endoscopic ultrasound-guided ethanol ablation (EUS-EA) has recently been introduced for the management of solid pancreatic tumors, including pancreatic neuroendocrine tumors (PNETs) and solid pseudopapillary tumors (SPTs). The study aims to evaluate the efficacy and predictive factors for response of EUS-EA in solid pancreatic tumors. METHODS: Between October 2015 and July 2021, 72 patients who underwent EUS-EA for solid pancreatic tumors were included. The study outcomes were to evaluate the efficacy of EUS-EA with complete remission (CR) and objective response, and their predictive factors. RESULTS: During follow-up, 47 patients were diagnosed with PNETs and 25 with SPTs. Eight cases reached CR and 48 reached objective response. When compared with SPTs, PNETs showed similar duration to reach CR (median not reached; p = 0.319), but shorter duration to reach objective response (PNETs: median 20.6 months, 95%CI 10.26-30.88; SPTs: median 47.7 months, 95%CI 18.14-77.20; p = 0.018). Ethanol dosage > 0.35 ml/cm3 shortened the duration to reach CR (median not reached; p = 0.026) and objective response (median 42.5 months, 95%CI 25.34-59.66 vs. 19.6 months, 95%CI 10.17-29.09; p = 0.006). CR had no significant predictive factors, but PNETs showed significant predictive factors for objective response (HR 3.34, 95%CI 1.07-10.43; p = 0.038). Twenty-seven patients experienced adverse events, and there were two severe cases. CONCLUSION: EUS-EA for pancreatic solid lesions seems feasible as a local treatment for patients who refuse or are unfit for surgery. Additionally, PNETs seem to be the better candidate for EUS-EA.

Diagnosis and surgical management of a rare neoplastic entity: Solid Pseudopapillary Neoplasm of the Pancreas.

INTRODUCTION AND IMPORTANCE: Solid Pseudopapillary Tumors of the Pancreas is an extremely rare pancreatic neoplastic entity that makes up barely 3 % of all types of exocrine pancreatic neoplasia. Symptoms vary and none of them are specific or pathognomonic for the disease. Therefore, delayed treatment or misdiagnoses could be the result. In turn, patients' morbidity and mortality significantly rise. Diagnosing or suspecting this type of critical type of neoplasia in the preoperative phase is a key component to performing appropriate and curative surgical interventions that result in increased patient survivability. CASE PRESENTATION: We hereby present the rare case of a previously healthy 20-year-old female whose chief complaints were chronic epigastric and left hypochondriac region pain and discomfort along with loss of appetite. During our preoperative radiological investigation, we found a cystic mass with well-defined borders located between the head of the pancreas and the second part of the duodenum. It measured (63 × 45 mm). No metastasis or lymph node involvement was elicited. CLINICAL DISCUSSION: The tumor was utterly resected via a successful Whipple procedure. A definitive diagnosis of a Solid Pseudopapillary Tumor was reached following meticulous histopathological and immunohistochemical analysis of the resected specimens. CONCLUSION: Based on our review of the published literature, no previously published cases from our country of pancreatic Solid Pseudopapillary Tumors exist. Documentation of this rare neoplasia is warranted to raise awareness and to establish the necessary clinical protocols to optimally diagnose, timely treat, and adequately follow up on patients who present with this malignancy.

Multimodality imaging differentiation of pancreatic neuroendocrine tumors and solid pseudopapillary tumors with a nomogram model: A large single-center study.

Background: Pancreatic neuroendocrine tumors (pNETs) and solid pseudopapillary tumors (SPTs) are two of the most common pancreatic neoplasms with different treatment procedures. However, the broad heterogeneity of pNETs and SPTs in clinical manifestations and radiological features often confuse the presurgical discrimination in clinical practice, and the clinical and molecular differentiation of the two tumors remains elusive to date. We presume that a large and comprehensive study into the multimodality features of pNETs and SPTs is necessary for precise clinical management. Methods: We collected and analyzed the clinicopathological information and multimodality features of nonfunctional pNET and SPT patients, for a total of 631 cases from 2006 to 2021. Univariate analysis of imaging features, including contrast-enhanced computed tomography (CT), magnetic resonance imaging, endoscopic ultrasound (EUS) and nuclear medicine imaging, and clinical characteristics was performed, and CT features and clinical information were integrated to establish a nomogram model. Results: We recruited 354 nonfunctional pNET and 277 SPT patients in our cohort. Regarding demographic information, pNET patients had a lower female percentage (55.4% vs. 72.9%), smaller tumor size (2.8 vs. 4.8 cm), and older age (53.4 vs. 35.3 years). In CT imaging and EUS, pNETs tended to appear as solid and homogenous lesions with strong enhancement intensity. Multifocal lesions, duct dilation, and lymph node (LN) enlargement were more likely to be observed in pNETs, while calcification was more common in SPT lesions. On positron emission tomography (PET)/CT, pNETs exhibited significant sensitivity to somatostatin receptor scintigraphy (SRS), with positive rates of 81.4% and 95% on 99mTc-HYNIC-TOC and 68Ga-DOTATATE PET/CT, respectively, while SPTs were all negative on SRS. Multivariate analysis identifies tumor size, age, enhancement intensity, calcification, and LN enlargement as statistically significant variables. Conclusions: Compared to SPT patients, pNET patients exhibit an older age and smaller tumor size. CT manifestations of strong intensity, LN enlargement, and no calcification could indicate a higher possibility of pNET. Meanwhile, the similarity in the immunohistochemical profile indicates that the two tumors could potentially develop from the same origin.

Age in combination with gender is a valuable parameter in differential diagnosis of solid pseudopapillary tumors and pancreatic neuroendocrine neoplasm.

BACKGROUND: The clinicopathological characteristics of solid pseudopapillary tumor (SPT) and pancreatic neuroendocrine neoplasm (pNEN) are different. We, therefore, systematically investigated the performance of the clinicopathological characteristics in distinguishing SPT from pNEN. METHODS: We collected the cases from the Surveillance, Epidemiology, and End Results Program. The International Classification of Diseases for Oncology, third edition (ICD-O-3) for tumors was used to identify patients with pNEN or patients with SPT. To determine the performance of age in combination with gender in distinguishing SPT from pNEN, a nomogram was developed and the performance of this nomogram was evaluated by the receiver operating characteristic curve and the area under the curve (AUC). RESULTS: In the training cohort, 563 patients with pNENs and 30 patients with SPTs were recruited. The logistic regression and receiver operating characteristic curves suggest that age, gender, T-stage, N-stage, and M-stage could discriminate SPT and pNEN. The AUC of age, gender, T-stage, N-stage, and M-stage was 0.82, 0.75, 0.65, 0.69, and 0.70, respectively. Based on the nomogram, we observed that the AUC of age and gender is significantly high than that of the T-stage, N-stage, and M-stage. CONCLUSIONS: The present study proposes a non-invasive nomogram that could aid in the differential diagnosis of pNEN and SPT. This might help the clinicians to distinguish SPT from pNEN and choose the appropriate treatments for the patients.

Retroperitoneal congenital epidermoid cyst misdiagnosed as a solid pseudopapillary tumor of the pancreas: A case report.

BACKGROUND: Retroperitoneal cysts are rare and usually asymptomatic abdominal lesions. Epidermoid cysts are frequent benign cutaneous tumors, but retroperitoneal localization of these cysts does not occur very often. CASE SUMMARY: We report a case report of a 25-year-old woman with a giant mass in the abdominal cavity. Because imaging examination indicated that the mass probably originated from the pancreas, the mass was considered a solid pseudopapillary tumor of the pancreas (SPTP). However, surgery revealed a retroperitoneal epidermoid cyst located behind the pancreas neck and the root of the superior mesenteric artery (SMA). We performed complete resection of the tumor. Postoperative pathology showed an epidermoid cyst. The patient fared well after two months of follow-up. CONCLUSION: Surgery is the gold standard for the diagnosis and treatment of retroperitoneal epidermoid cysts. Retroperitoneal epidermoid cysts around the pancreas are easily misdiagnosed as cystic SPTPs. Surgeons should pay particular attention to preoperative diagnosis to reduce severe surgical complications and improve the quality of life of patients.

Clinical characteristics, surgical strategies, and outcome of solid pseudopapillary tumor of the pancreas: retrospective analysis in a single center.

INTRODUCTION: Solid pseudopapillary tumor of the pancreas (SPTP) is a rarely diagnosed, low-malignancy pancreatic neoplasm, which mostly can be cured by surgery. AIM: To investigate the surgical effect and prognosis of SPTP. MATERIAL AND METHODS: The data of 39 patients diagnosed with SPTP and treated with surgery between 2013 and 2020 were analyzed retrospectively. The data included the clinical characteristics, surgical management, pathological findings and therapeutic outcome. RESULTS: The mean age of the patients was 34.0 ±12.1 years, and the female : male ratio was 32 : 7. Most of the patients were asymptomatic (48.7%). The mean diameter of the tumors was 4.81 ±2.36 cm. Operative procedures were conducted according to the location and size of the tumors. Laparoscopic surgery, especially laparoscopic distal pancreatectomy (LDP), provided a smaller incision, a shorter postoperative hospital stay and a shorter postoperative fasting time. There was no observed difference in the amount of blood loss or complication rate. The median follow-up was 24 months. One patient with 20% expression of Ki-67 developed liver metastasis after surgery. CONCLUSIONS: SPTP is a rare disease with low malignancy. Minimally invasive surgery, especially LDP, has been proven to be a feasible and safe treatment method for SPTP with early recovery. The prognosis of SPTP is favorable. Lifetime surveillance is necessary especially in patients with a high expression rate of Ki-67.