Solid pseudo-papillary tumors of the pancreas: current update

Diagnostics and Management of Pancreatic Cystic Lesions-New Techniques and Guidelines

Pancreatic cystic lesions (PCLs) are increasingly diagnosed owing to the wide use of cross-sectional imaging techniques. Accurate identification of PCL categories is critical for determining the indications for surgical intervention or surveillance. The classification and management of PCLs rely on a comprehensive and interdisciplinary evaluation, integrating clinical data, imaging findings, and cyst fluid markers. EUS (endoscopic ultrasound) has become the widely used diagnostic tool for the differentiation of pancreatic cystic lesions, offering detailed evaluation of even small pancreatic lesions with high sensitivity and specificity. Additionally, endoscopic ultrasound-fine-needle aspiration enhances diagnostic capabilities through cytological analysis and the assessment of fluid viscosity, tumor glycoprotein concentration, amylase levels, and molecular scrutiny. These detailed insights play a pivotal role in improving the clinical prognosis and management of pancreatic neoplasms. This review will focus mainly on the latest recommendations for the differentiation, management, and treatment of pancreatic cystic lesions, highlighting their clinical significance.

Solid pseudopapillary tumor of pancreas: A report of two cases and literature review

Solid pseudopapillary neoplasm of the pancreas is rarely encountered in clinical practice. It is a tumor with a good prognosis and overall curative rates. It primarily affects young females in their twenties. It has characteristic imaging appearances, but a definite diagnosis requires histopathological examination. The treatment goal of solid pseudopapillary neoplasm is almost always curative and aims for complete resection of the mass. Here, we present 2 cases of this rare neoplasm. The first case was managed by laparoscopic distal pancreatectomy, while the second underwent a Whipple procedure for pancreatic head involvement.

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.

Pancreatic metastasis of leiomyoma found 27 years after uterine fibroid surgery

A 59-year-old female was referred to our hospital for pancreatic tumor. She had undergone resection of uterine fibroids 27 years ago, and leiomyoma in the left thigh 8 years ago. Tumor markers were normal. A well-defined hypoechoic tumor measuring 26 mm × 22 mm was detected at the pancreatic tail using ultrasound. Inside the tumor, a small cystic structure was observed. High-sensitivity Doppler imaging revealed faint signals indicating blood flow from the periphery to the interior. Contrast-enhanced ultrasonography in the arterial phase revealed slow, heterogenous enhancement from the periphery to the center of the mass that occurred later than that in the pancreatic parenchyma. The tumor then exhibited homogeneous enhancement except for the periphery, with subsequent washout. Endoscopic ultrasound-fine-needle aspiration was performed. Histopathological examination diagnosed a leiomyoma. The left thigh tumor resected 8 years ago had been diagnosed as benign metastatic leiomyoma (BML). We considered that the current pancreatic tumor was also BML clinically. We report this case because pancreatic metastasis from uterine fibroids is extremely rare. Uterine fibroids are benign tumors, but there are rare cases of metastasis to various organs, which should be considered when performing ultrasound.

Rare Solid Pancreatic Lesions on Cross-Sectional Imaging

Several solid lesions can be found within the pancreas mainly arising from the exocrine and endocrine pancreatic tissue. Among all pancreatic malignancies, the most common subtype is pancreatic ductal adenocarcinoma (PDAC), to a point that pancreatic cancer and PDAC are used interchangeably. But, in addition to PDAC, and to the other most common and well-known solid lesions, either related to benign conditions, such as pancreatitis, or not so benign, such as pancreatic neuroendocrine neoplasms (pNENs), there are solid pancreatic lesions considered rare due to their low incidence. These lesions may originate from a cell line with a differentiation other than exocrine/endocrine, such as from the nerve sheath as for pancreatic schwannoma or from mesenchymal cells as for solitary fibrous tumour. These rare solid pancreatic lesions may show a behaviour that ranges in a benign to highly aggressive malignant spectrum. This review includes cases of an intrapancreatic accessory spleen, pancreatic tuberculosis, solid serous cystadenoma, solid pseudopapillary tumour, pancreatic schwannoma, purely intraductal neuroendocrine tumour, pancreatic fibrous solitary tumour, acinar cell carcinoma, undifferentiated carcinoma with osteoclastic-like giant cells, adenosquamous carcinoma, colloid carcinoma of the pancreas, primary leiomyosarcoma of the pancreas, primary and secondary pancreatic lymphoma and metastases within the pancreas. Therefore, it is important to determine the correct diagnosis to ensure optimal patient management. Because of their rarity, their existence is less well known and, when depicted, in most cases incidentally, the correct diagnosis remains challenging. However, there are some typical imaging features present on cross-sectional imaging modalities that, taken into account with the clinical and biological context, contribute substantially to achieve the correct diagnosis.

The Role of MRI in the Diagnosis of Solid Pseudopapillary Neoplasm of the Pancreas and Its Mimickers: A Case-Based Review with Emphasis on Differential Diagnosis

Solid pseudopapillary neoplasm (SPN) is rare pancreatic tumor occurring most commonly in young females. The typical imaging appearance of SPN is of well-defined, encapsulated, and large heterogeneous tumors, consisting of solid and cystic components due to various degrees of intralesional hemorrhage and necrosis. However, atypical imaging presentation in the form of small solid tumors or uniformly cystic lesions might also be seen, which can be explained by specific pathological characteristics. Other imaging features such as a round shape, the absence of main pancreatic duct dilatation, and slow growth, in combination with vague symptoms, favor the diagnosis of SPNs. Nevertheless, the radiological findings of SPN might overlap with other solid and cystic pancreatic neoplasms, such as neuroendocrine tumors, serous and mucinous neoplasms, and even small pancreatic adenocarcinomas. In addition, a few benign non-tumorous conditions including walled-of-necrosis, and intrapancreatic accessory spleen may also pose diagnostic dilemmas simulating SPNs on imaging studies. The aim of this manuscript is to provide a comprehensive overview of the typical and atypical imaging features of SPNs and to describe useful tips for differential diagnosis with its potential mimickers.

Solid Pseudopapillary Neoplasms of the Pancreas: a Single-Center Experience and Review of the Literature

PURPOSE

Pancreatic solid pseudopapillary neoplasms (SPNs) are rare borderline tumours mainly affecting young female patients. The number of patients diagnosed with SPNs has increased significantly in the last decades owing to the increased use of cross-sectional imaging investigating different abdominal symptoms, whilst a significant proportion are incidentally discovered during the process of evaluating other pathologies. We herein present our institutional experience of patients with SPN who underwent curative resection focusing on clinical, pathological features, and the long-term outcomes.

METHODS

All patients undergoing pancreatectomy in our institution for SPN from January 2010 until December 2018 were included. Clinical, perioperative, histological, and long-term outcomes were collected and analysed.

RESULTS

During the inclusion period, a total of 19 patients had a pathological diagnosis of SPNs after surgical resection. Sixteen of them were female (84%), while the median patient age was 30 (range 16-66) years. Nine patients (47%) underwent distal pancreatectomy and splenectomy, 2 (11%) underwent spleen preserving distal pancreatectomy, 6 (32%) underwent pancreatoduodenectomy, one (5%) underwent total pancreatectomy, and one (5%) central pancreatectomy. Seventeen patients underwent R0 resection. During a median follow-up of 23 months, no tumour recurrence or death was recorded.

CONCLUSION

In our experience, SPNs are rare tumours with low malignant potentials. Surgical resection remains the gold standard treatment and is associated with good prognosis.

The Prognostic Factors of Preoperative Prognostic Nutritional Index and Radiological Findings of Solid Pseudopapillary Tumors of Pancreas: A Single-Center Experience of 14 Years

Introduction

Solid pseudopapillary tumors of pancreas (SPTP) is an indolent rare tumor with malignant potential. The prediction of malignancy is an enigma. The aim of this study is to explore the relationship between operative measurements and malignancy prognosis of SPTP patients.

Methods

A cohort of consecutive 102 patients were enrolled in this study. Preoperative measurements and clinical outcomes were analyzed.

Results

Eighteen patients (17.6%) were confirmed as malignant. The malignant SPTP of the optimal cut-off value was 47.9 (p=0.012) for prognostic nutritional index (PNI). The value of PNI≤47.9 and incomplete capsule were significantly correlated with malignancy. Univariate analysis showed that the PNI≤47.9 (p=0.013) and incomplete capsule (p<0.001) were predictors of disease-specific survival (DSS). Multivariate analysis identified the PNI≤47.9 (p=0.036) and incomplete capsule (p=0.023) as the independent prognostic factors of DSS. The new score of 0,1,2 based on PNI and capsule presence stratified the patients into 3 groups. The patients with low PNI and incomplete capsule achieved the worst prognosis.

Conclusion

The combination test of operative PNI and capsule presence would be a reliable indicator of the aggressive natural history of SPTP.

Molecular markers contribute to the clinical diagnosis for pancreatic cystic neoplasms

A pancreatic cystic neoplasm (PCN) is a rare pancreatic disease. Malignant PCNs are usually identified incidentally while evaluating other lesions. However, PCNs are being identified more frequently owing to the increased use of abdominal imaging. Malignant PCNs have complicated and diverse biological behaviors, including various malignant risk factors, diverse molecular features, natural history, and complex pathological classifications. Although many diagnostic methods, such as cross-sectional imaging and endoscopic evaluation, have been developed, malignant PCNs are still difficult to differentiate from benign tumors. On searching for related articles in the recent decade, we found that some molecular biomarkers such as carcinoembryonic antigen could be useful for discriminating between malignant tumors and benign tumors. However, cytopathologic evaluation is the most useful method for differentiating between benign and malignant lesions. Although cytopathologic evaluation has a specificity of 100% for identifying malignancies, its accuracy is often hampered by the low cellularity of PCN cells in the cystic fluid. Herein, we review the progress in the use of cellular and molecular markers for the accurate identification of PCNs.

A systematic review and meta-analysis of predictors of recurrence in patients with Solid Pseudopapillary Tumors of the Pancreas

BACKGROUND

The recurrence rates and predictors of recurrence in patients with Solid Pseudopapillary tumors (SPT) are unclear, which makes it challenging to determine the duration of follow-up. The aim of the current study was to perform a systematic review and meta-analysis to determine the recurrence rates and pathologic factors associated with recurrence in patients with SPT.

METHODS

A PubMed, Scopus, and Web of Science search was conducted to identify studies of SPT published during the last 15 years: (09/2002-09/2017). Studies reporting on patients with SPT and follow-up of >5 years were included. The search strategy was conducted per 2009 PRISMA guidelines.

RESULTS

A total of 103 studies reporting on 2599 non-metastatic SPT patients were identified. Sixty-nine patients (2.6%) developed recurrence during follow-up. Pooled estimates from studies with a sample size >20 (N = 33) noted an overall recurrence rate of 2% (95% CI 1-2%). Male gender (OR 1.960), positive lymph nodes (OR 11.9), R1 margins (OR 11.1), and LVI (OR 5.5), were associated with a significantly (all p < 0.05) increased risk of recurrence.

CONCLUSION

Current meta-analysis suggests that only 2% of patients with SPT experience recurrence after resection. These data will guide the treating physicians and patients regarding recurrence rates and help identify patients at increased risk of recurrence during follow-up.

CT and MR imaging features of pancreatic adenosquamous carcinoma and their correlation with prognosis

PURPOSE

To retrospectively investigate the computed tomography (CT) and magnetic resonance (MR) imaging features of pancreatic adenosquamous carcinoma (PASC) and the association between imaging findings and prognosis.

MATERIALS AND METHODS

CT, MR images of 26 patients with PASC were analyzed. Clinical symptoms, tumor markers, and patients' survival were recorded. Tumor attenuation, enhancement pattern and degree, vessel involvement, adjacent tissue invasion and metastasis were evaluated. The association between imaging features and overall survival (OS) were also assessed using Cox proportional hazards ratio model.

RESULTS

Fourteen masses were found in the head of the pancreas and 12 in the body/tail. The mean tumor size was 4.47 ± 1.76 cm. PASC usually showed ill-defined (96.2%), lobulated (76.9%) and predominantly solid mass (92.3%). Ring enhancement in the peripheral area of the tumor was commonly seen (76.9%). Vessel invasion was seen in 17 cases (65.4%), encasement of adjacent arteries in 7 cases (26.9%), upstream main pancreatic duct (MPD) dilatation in 16 cases (61.5%) and double duct sign in 9 cases (34.6%). Multivariate Cox proportional hazards model demonstrated that patients with vessel invasion may predict a poor prognosis (p = 0.037).

CONCLUSION

PASC tends to be an ill-defined solid mass with peripheral ring enhancement, and relatively poor enhancement in the central area. PASC may also show vessel invasion, vessel encasement and upstream MPD dilatation. Vessel invasion may indicate a poor prognosis.

MRI evaluation of pancreatic ductal adenocarcinoma: diagnosis, mimics, and staging

The radiologist's role in the evaluation of pancreatic ductal adenocarcinoma remains critical in the management of this deadly disease. Imaging plays a vital role in the diagnosis and staging of pancreatic cancer. Although CT is more commonly used for staging pancreatic cancer, MR is increasingly playing an important role in this regard. In our institution, all pancreatic malignancies undergo staging with MRI. In this pictoral essay, we illustrate the MR imaging features of pancreatic ductal adenocarcinoma and its mimics, and we also discuss pearls and pitfalls in MR staging of pancreatic carcinoma.

Radiological Workup of Cystic Neoplasms of the Pancreas

Pancreatic cystic lesions are being detected with increasing frequency because of increased use and improved quality of cross-sectional imaging techniques. Pancreatic cystic lesions encompass non-neoplastic lesions (such as pancreatitis-related collections) and neoplastic tumors. Common cystic pancreatic neoplasms include serous cystadenomas, mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, and solid pseudopapillary tumors. These cystic pancreatic neoplasms may have typical morphology, but at times show overlapping imaging features on cross-sectional examinations. This article reviews the classical and atypical imaging features of commonly encountered cystic pancreatic neoplasms and presents the limitations of current cross-sectional imaging techniques in accurately classifying pancreatic cystic lesions.

Pancreatic Cystic Lesions: Pathogenesis and Malignant Potential

Pancreatic cancer remains one of the most lethal cancers despite extensive research. Further understanding of precursor lesions may enhance the ability to treat and prevent pancreatic cancer. Pancreatic cystic lesions (PCLs) with malignant potential include: mucinous PCLs (intraductal papillary mucinous neoplasms and mucinous cystic neoplasm), solid pseudopapillary tumors and cystic neuroendocrine tumors. This review summarizes the latest literature describing what is known about the pathogenesis and malignant potential of these PCLs, including unique epidemiological, radiological, histological, genetic and molecular characteristics.

Imaging mimics of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma is the most common primary malignancy of the pancreas. The classic imaging features are a hypovascular mass with proximal ductal dilatation. Different pancreatic pathologies can mimic the imaging appearance of carcinoma including other tumors involving the pancreas (pancreatic neuroendocrine tumors, lymphoma, metastasis, and rare tumors like pancreatic acinar cell carcinoma and solid pseudopapillary tumors), inflammatory processes (chronic pancreatitis and autoimmune pancreatitis), and anatomic variants (annular pancreas). Differentiation between these entities can sometimes be challenging due to overlap of imaging features. The purpose of this article is to describe the common entities that can mimic pancreatic cancer on imaging with illustrative examples and to suggest features that can help in differentiation of these entities.

First robotic pylorus preserving pancreaticoduodenectomy for Frantz's tumour in an adolescent girl

Solid pseudopapillary tumour (SPT) is one of the uncommon benign cystic neoplasms of pancreas occurring predominantly in young females. Being benign in nature, surgical resection is the treatment of choice with excellent 5-year survival. A 14-year-old girl presented with pain abdomen for 1 week. On evaluation, she was found to have a large SPT involving head and uncinate process of Pancreas She underwent robotic pylorus preserving pancreaticoduodenectomy (R-PPPD) with da Vinci® Si Robotic System (Intuitive Surgical, Sunnyvale, CA, USA). The total operating time was 480 min. Her postoperative recovery was uneventful and she was discharged on postoperative day 6. In the era of minimally invasive surgery, robotic pancreatic resection and reconstruction are becoming more acceptable. Although the operating domain is small in younger age group, the precise movement of robotic arm and high quality magnified three-dimensional view allows the surgeons to perform PPPD on younger patients also. Young female patients suffering from SPTs can electively undergo R-PPPD with minimal morbidity and mortality. R-PPPD can become the treatment of choice for SPTs involving pancreatic head region even in paediatric and adolescent age group.

Solid pseudopapillary neoplasm of the pancreas: CT imaging features and radiologic-pathologic correlation

PURPOSE

We aimed to evaluate the imaging features of solid pseudopapillary neoplasm (SPN) of the pancreas with an emphasis on radiologic-pathologic correlation.

METHODS

Ten patients (all female; mean age, 32 years) with histologic or cytologic diagnosis of SPN encountered between January 2007 and December 2013 were included in this study. Preoperative computed tomography (CT) images were reviewed for location, attenuation, enhancement pattern, margin, shape, size, morphology, presence of capsule and calcification. CT appearances were correlated with histopathologic findings.

RESULTS

Tumors in the distal pancreatic body and tail had a tendency to be larger (mean size 12.6 cm vs. 4.0 cm). Six of the nine tumors that were resected had a fibrous pseudocapsule at histology, five of which could be identified on CT scan. Eight lesions had mixed hypoenhancing solid components and cystic areas corresponding to tumor necrosis and hemorrhage. The two smallest lesions were purely solid and nonencapsulated. Varied patterns of calcification were seen in four tumors. Three of the four pancreatic tail tumors invaded the spleen. At a median follow-up of 53 months, there was no evidence of recurrence in the nine patients who underwent surgical resection of the tumor.

CONCLUSION

A mixed solid and cystic pancreatic mass in a young woman is suggestive of SPN. However, smaller lesions may be completely solid. Splenic invasion can occur in pancreatic tail SPNs; however, in this series it did not adversely affect the long-term outcome.

SOLID PSEUDOPAPILLARY NEOPLASM OF THE PANCREAS

BACKGROUND

The solid pseudopapillary neoplasm is a rare tumor of the pancreas. However, it´s etiology still maintain discussions.

AIM

To analyze it´s clinical data, diagnosis and treatment.

METHODS

A retrospective study of medical records of all patients treated from January 1997 until July 2015.

RESULTS

Were identified 17 cases. Most patients were women (94.11%) and the average age was 32.88 years. The main complaint was abdominal mass (47.05%). The most frequent location was in the body/tail of the pancreas (72.22%) and the most frequently performed surgery was distal pancreatectomy with splenectomy (64.70%). No patient had metastases at diagnosis. Conservative surgery for pancreatic parenchyma was performed in only three cases. The rate of complications in the postoperative period was 35.29% and the main complication was pancreatic fistula (29.41%). No patient underwent adjuvant treatment.

CONCLUSIONS

The treatment is surgical and the most common clinical presentation is abdominal mass. Distal pancreatectomy with splenectomy was the most frequently performed surgery for its treatment.

A, Lima S, Cardoso E, Brito E, Macedo-Lima M, Lyra Jr. D, Lyra P, Lima MM. Solid pseudopapillary tumor of the pancreas: Clinical features, diagnosis and treatment

Summary Introduction: Solid pseudopapillary tumor of the pancreas (SPTP) is a rare neoplasm of low malignant potential with uncertain behavior, diagnosed mainly in young women. Method: Our report comprises a series of cases of SPTP reviewed retrospectively, highlighting clinical, tomographic and immunohistochemical features, treatment performed and outcomes. Results: Thirteen patients were found to have pancreatic [solid] masses on computed tomography scan measuring a mean diameter of 8.8 cm. All patients underwent complete surgical excision. Immunohistochemistry confirmed diagnosis in all cases. Conclusion: SPTP occurs more frequently in young women. Diagnostic suspicion lies on the finding of a bulky, solid and cystic pancreatic mass. Imaging findings might provide diagnostic information before resection. Conservative approaches can be used in selected cases and survival rates are usually excellent following complete resection.

[Diagnostic strategy and differential therapeutic approach for cystic lesions of the pancreas]

CLINICAL/METHODICAL ISSUE

Cystic pancreatic lesions (CPL) are diagnosed with increasing frequency. Because up to 60% of CPL are classified as malignant or premalignant, every CPL should be fully investigated and clarified. Serous CPL with low risk of malignancy must be differentiated from mucinous CPL with relevant potential malignancy (intraductal papillary mucinous neoplasm IPMN) and mucinous cystic neoplasm (MCN) as well as from harmless pseudocysts.

STANDARD RADIOLOGICAL METHODS

Cross-sectional imaging with computed tomography (CT) and magnetic resonance imaging (MRI) plays a crucial role in the diagnostics of CPL.

METHODICAL INNOVATIONS

An algorithm for the differential diagnostic classification of CPL is presented.

PERFORMANCE

The connection to the pancreatic duct is the key diagnostic criterion to differentiate IPMN from all other CPL. An exception to this rule is that pseudocysts can also show a connection to the pancreatic duct. A further classification of CPL with no connection to the pancreatic duct can be made by morphological criteria and correlation of the radiological findings with patient age, sex, history and symptoms.

PRACTICAL RECOMMENDATIONS

Depending on the diagnosis and hence the malignant potential the indications for surgery or watch and wait have to be discussed in an interdisciplinary cooperation. Due to its higher soft tissue contrast MRI is often superior to CT for depiction of CPL morphology.

Comparison of Multidetector CT and Gadobutrol-Enhanced MR Imaging for Evaluation of Small, Solid Pancreatic Lesions

OBJECTIVE

To compare multidetector computed tomography (MDCT) and MRI for lesion conspicuity, as well as the detection and characterization of small solid pancreatic lesions (SPLs).

MATERIALS AND METHODS

193 patients with small SPLs (< 3 cm) and 52 patients with normal pancreas who underwent both multiphasic MDCT and gadobutrol-enhanced MRI were included in our study. Two radiologists blinded to the pathologic diagnoses independently reviewed those images, and determined the detection of "SPL per se" and "SPL in consideration of secondary features", the lesion conspicuity, the probability of pancreatic ductal adenocarcinoma (PDAC), and the most likely specific diagnosis.

RESULTS

The sensitivity of MRI for "detection of SPL per se" was significantly higher than that of CT in both reviewers: 92.7% (179/193) and 97.9% (189/193), respectively, for reviewer 1 (p = 0.031) and 90.7% (175/193) and 99.5% (192/193), respectively, for reviewer 2 (p < 0.001). In addition, MRI provided better lesion conspicuity than MDCT for both reviewers (p < 0.001). However, CT and MRI did not show significant difference in sensitivity for "detection of SPL in consideration of secondary features", specificity for SPL detection, and differentiation of PDAC vs. non-PDAC (p > 0.05). The accuracies of CT and MRI for making a specific diagnosis were as follows: 85.7% (210/245) vs. 86.9% (213/245), respectively, for reviewer 1 (p = 0.736), and 91.8% (225/245) vs. 93.5% (229/245), respectively, for reviewer 2 (p = 0.454).

CONCLUSION

MRI showed better lesion conspicuity than MDCT, but did not show significantly different diagnostic performance compared with MDCT for detecting and characterizing small SPLs.

Adenosquamous carcinoma of pancreas: CT and MR imaging features in eight patients, with pathologic correlations and comparison with adenocarcinoma of pancreas

PURPOSE

To reveal the CT and MR imaging features of adenosquamous carcinoma of pancreas (ASqC) in eight patients.

METHODS

This study was approved by our institutional review board. Eight patients with ASqC were included in this study. Radiologic and pathologic findings were reviewed in each lesion. Additionally, radiologic imaging findings were compared between ASqC and controlled adenocarcinoma groups.

RESULTS

Significant differences between ASqC and adenocarcinoma groups were noted in lesion shape, enhancement pattern on dynamic CT images, the presence or absence of necrosis, and tumor thrombus in the portal vein (PV) system. Compared with adenocarcinoma, ASqC tended to be round-lobulated shape (100% vs. 57.6%), have necrotic portions (100% vs. 39.4%), and have tumor thrombus in the PV system (37.5% vs. 6.1%). Extensive central necrosis was found in six (75%) of ASqC lesions. More lesions in ASqC group (62.5% vs. 12.1%) showed the highest absolute attenuation on pancreatic arterial phase (PAP) or portal venous phase (PVP) images, although the average attenuation values of all ASqC lesions on PAP, PVP, and delayed phase images were almost the same. Five (83.3%) of six resected lesions appeared as nodular type macroscopically. Microscopically, all lesions did not show infiltrating growth pattern, but showed an intermediate growth pattern, and were surrounded incompletely by fibrous tissue.

CONCLUSIONS

ASqC tended to be a round-lobulated lesion with extensive central necrosis. Additionally, tumor thrombus in the PV system was often present. These CT and MR imaging features could be a useful clue for diagnosing ASqC.

Solid Pseudopapillary Tumor in a Pregnant Woman: Imaging Findings and Literature Review

A solid pseudopapillary neoplasm is a rare pancreatic tumor accounting for 1-2% of exocrine pancreatic neoplasms. It is usually asymptomatic and discovered incidentally. It is mainly seen in young women between the second and third decades of life. Although it usually has a large size at the time of diagnosis, it is considered to have low malignant potential. Solid pseudopapillary tumors (SPTs) have characteristic magnetic resonance imaging (MRI) features that enable it to be differentiated from other more common pancreatic tumors. Here, we report the case of a 34-year-old pregnant woman who was admitted to The Royal Hospital, Oman, with a large mass in her pancreas, which was incidentally discovered during abdominal ultrasonography. The mass was investigated further with MRI. The MRI revealed a well-defined mass related to the tail and body of the pancreas with solid and cystic components. It had a heterogeneous texture with fluid levels of different signal intensities due to the presence of blood of different ages. The cystic-solid appearance of an encapsulated lesion with characteristic signal intensity on MRI suggested the possibility of a SPT. Postoperative histopathology results confirmed the diagnosis of a SPT. In this case report, we highlight the MRI features of a SPT and discuss how to differentiate it from other cystic pancreatic tumors to increase the awareness of clinicians to this rare pancreatic tumor.

Imaging of pancreatic neoplasms

Ductal adenocarcinoma accounts for 85% to 90% of all solid pancreatic neoplasms, is increasing in incidence, and is the fourth leading cause of cancer-related deaths. There are currently no screening tests available for the detection of ductal adenocarcinoma. The only chance for cure in pancreatic adenocarcinoma is surgery. Imaging has a crucial role in the identification of the primary tumor, vascular variants, identification of metastases, disease response assessment to treatment, and prediction of respectability. Pancreatic neuroendocrine neoplasms can have a distinctive appearance and pattern of spread, which should be recognized on imaging for appropriate management of these patients.

Magnetic resonance imaging of less common pancreatic malignancies and pancreatic tumors with malignant potential

Pancreatic tumors are an increasingly common finding in abdominal imaging. Various kinds of pathologies of the pancreas are well known, but it often remains difficult to classify the lesions radiologically in respect of type and grade of malignancy. Magnetic resonance imaging (MRI) is the method of choice for the evaluation of pancreatic pathologies due to its superior soft tissue contrast. In this article we present a selection of less common malignant and potentially malignant pancreatic neoplasms with their characteristic appearance on established MRI sequences with and without contrast enhancement.

Solid-pseudopapillary tumor of the pancreas: MR imaging findings in 21 patients

PURPOSE

Solid-pseudopapillary tumor (SPT) of the pancreas is a rare, low-grade malignancy, which mostly occurs in adolescent and young adult females. The goal of this study was to retrospectively analyze the magnetic resonance (MR) imaging presentation of SPT of the pancreas.

METHODS

We retrospectively reviewed the preoperative MR imaging examinations and the medical, surgical and histopathological records of 21 patients who underwent surgery for SPT of the pancreas. MR imaging included T1-weighted, T2-weighted, and gadolinium chelate-enhanced MR imaging. In addition, 10 patients had diffusion-weighted (DW) MR imaging. MR examinations were retrospectively reviewed for location, size, morphological features and signal intensity of the tumors.

RESULTS

Nineteen women and 2 men (median age, 23 years; range, 14-59) were included. Seven patients (7/21; 33%) presented with abdominal symptoms. The median largest tumor diameter was 53mm (range, 32-141 mm). SPTs were located in the pancreatic head, body, and tail in 9 (9/21; 43%), 5 (5/21; 24%) and 7 (7/21, 33%) patients, respectively. All patients (21/21; 100%) had a single SPT. SPTs were more frequently oval (12/21; 57%), predominantly solid (12/21; 57%), fully encapsulated (16/21; 76%), larger than 30 mm (21/21; 100%), hypointense on T1-weighted MR images (21/21, 100%), hyperintense on T2-weighted MR images (21/21; 100%) and with an enhancing capsule after gadolinium-chelate administration (21/21; 100%).

CONCLUSIONS

There is trend of appearance for SPT of the pancreas on MR imaging but that variations may be observed in a number of cases. SPT uniformly presents as a single, well-demarcated and encapsulated pancreatic mass.