Small (<or=3 cm) solid pseudopapillary tumors of the pancreas at multiphasic multidetector CT

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.

Pancreatic Cancer and Its Mimics

Pancreatic ductal adenocarcinoma (PDAC) is the most common primary pancreatic malignancy, ranking fourth in cancer-related mortality in the United States. Typically, PDAC appears on images as a hypovascular mass with upstream pancreatic duct dilatation and abrupt duct cutoff, distal pancreatic atrophy, and vascular encasement, with metastatic involvement including lymphadenopathy. However, atypical manifestations that may limit detection of the underlying PDAC may also occur. Atypical PDAC features include findings related to associated conditions such as acute or chronic pancreatitis, a mass that is isointense to the parenchyma, multiplicity, diffuse tumor infiltration, associated calcifications, and cystic components. Several neoplastic and inflammatory conditions can mimic PDAC, such as paraduodenal "groove" pancreatitis, autoimmune pancreatitis, focal acute and chronic pancreatitis, neuroendocrine tumors, solid pseudopapillary neoplasms, metastases, and lymphoma. Differentiation of these conditions from PDAC can be challenging due to overlapping CT and MRI features; however, certain findings can help in differentiation. Diffusion-weighted MRI can be helpful but also can be nonspecific. Accurate diagnosis is pivotal for guiding therapeutic planning and potential outcomes in PDAC and avoiding biopsy or surgical treatment of some of these mimics. Biopsy may still be required for diagnosis in some cases. The authors describe the typical and atypical imaging findings of PDAC and features that may help to differentiate PDAC from its mimics. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center. See the invited commentary by Zins in this issue.

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.

Pancreatic Cystic Lesions: Imaging Techniques and Diagnostic Features

The detection of incidental pancreatic cystic lesions has increased over time. It is crucial to separate benign from potentially malignant or malignant lesions to guide management and reduce morbidity and mortality. The key imaging features used to fully characterize cystic lesions are optimally assessed by contrast-enhanced magnetic resonance imaging/magnetic resonance cholangiopancreatography, with pancreas protocol computed tomography offering a complementary role. While some imaging features have high specificity for a particular diagnosis, overlapping imaging features between diagnoses may require further investigation with follow-up diagnostic imaging or tissue sampling.

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.

Can solid pseudopapillary neoplasm of the pancreas without degeneration be diagnosed with imaging? a comparison study of the solid component of solid pseudopapillary neoplasm, neuroendocrine neoplasm, and ductal adenocarcinoma

PURPOSE

To investigate the MR findings of the solid components within pancreatic solid pseudopapillary neoplasms (SPNs) to characterize solid SPN without degeneration.

METHODS

After case matching, 23 patients with SPNs, 23 with pancreatic neuroendocrine neoplasms (PNENs), and 46 pancreatic ductal adenocarcinomas (PDACs) were included in this retrospective comparative study. The MR findings of the solid components within the pancreatic tumors were assessed qualitatively and semi-quantitatively.

RESULTS

In the qualitative assessment, significant differences were noted in T2-weighted imaging and MR cholangiopancreatography (MRCP). SPNs with a score of 4-5 (iso- to hyper-intense compared with the renal cortex) were observed in 18/19 (94.7%) by reader 1 and 15/19 (78.9%) by reader 2 (score 5, 52.6% and 47.4%) on fast spin-echo (FSE) T2-weighted imaging. On MRCP, the two readers identified 12 (63.2%) and 8 (42.1%) SPNs, respectively. The semi-quantitative signal-intensity ratio (SIR, signal intensity of tumor/signal intensity of the pancreatic parenchyma) of SPNs on FSE T2-weighted imaging was significantly higher (mean, 1.99-2.01) than that of PNENs (1.30-1.31) or PDACs (1.26-1.28). The sensitivity/specificity of 'hyper' on T2-weighted imaging (qualitative score of 4-5, or SIR of ≥ 1.5) were 78.9-100.0%/63.8-79.7%. The sensitivity/specificity of 'remarkably hyper' (score of 5, SIR of ≥ 2.0, or visible on MRCP) or salt-and-pepper pattern were 36.8-68.4%/85.5-98.6%.

CONCLUSION

T2-weighted imaging may be the key sequence for solid SPN. Solid tumors with hyper-intensity on T2-weighted imaging (especially, more hyper-intense than the renal cortex, more than twice the signal of the pancreatic parenchyma, depicted on MRCP, or salt-and-pepper appearance) may be suspected to be SPNs.

Presumed radiological diagnosis of solid pseudopapillary tumors: do we really know what we are watching?

OBJECTIVES

Little is known about the clinicians' ability to ascertain the identity of a pancreatic lesion as solid pseudopapillary tumors (SPT)preoperatively. We led this retrospective study to figure out the disease spectrum that mimic SPT, the key features of SPT and the accuracy of CT and MRI in characterizing them.

METHODS

Radiological and clinical database at a tertiary pancreatic disease center (Peking Union Medical College Hospital) was searched for patients who received CT or MRI with a presumed radiological diagnosis of SPT. Those patients' clinical information and final pathological diagnosis were collected.

RESULTS

During 2018.10-2021.12, 200 patients had a presumed radiological diagnosis of SPT, and 132 of them had unambiguous pathological diagnosis. SPT were confirmed in only 63.6% (84/132), while the others had a variety of neoplastic and nonneoplastic lesions, including pancreatic neuroendocrine tumors (n = 15), pseudocysts (n = 4), mucinous cystic neoplasms (n = 4), serous cystadenomas (n = 3), neural sheath tumors (n = 3), lymphoepithelial cysts (n = 2), and several very rare pathologies (n = 17). Of note, 11.4% (15/132) of those were benign or nonneoplastic lesions, while 6.8% (9/132) were neoplasms with highly aggressive nature, or pancreatic metastases, which require systematic evaluation and staging instead of upfront surgery. Retrospective radiological analysis based on key imaging features, clinical history and laboratory findings had an improved diagnostic accuracy of 78.5% with CT and 77.8% with MRI.

CONCLUSIONS

There is a broad disease spectrum mimicking SPT at CT and MRI. Key imaging features, clinical information and laboratory findings must be integrated to improve the diagnostic accuracy.

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.

A case of solid-type pancreatic hamartoma presenting high apparent diffusion coefficient value: histopathological correlation and literature review

Pancreatic hamartoma is a rare tumor-like malformation and could mimic other pancreatic tumors including malignant neoplasm. Due to its rarity, magnetic resonance (MR) imaging findings including those diffusion-weighted (DW) imaging have not been clarified. We present a curious case of pancreatic hamartoma presenting high apparent diffusion coefficient (ADC) value with histopathological correlation. A 49-year-old woman with a pancreatic mass found incidentally on ultrasonography for medical checkup was referred to our institution for further examination and treatment because it slightly enlarged in the follow-up examination. Contrast-enhanced computed tomography (CT) and gadoxetic acid disodium-enhanced MR imaging revealed a well-demarcated solid mass of 13 mm in diameter in the pancreas body, which was gradually and homogeneously enhanced in the delayed/transient phase. It showed hyper intensity on T2-weight and DW images, and the mean ADC value was high (1.86 × 10^-3mm²/s). Laparoscopic distal pancreatectomy was conducted with suspicious preoperative diagnosis of pancreatic hypovascular neuroendocrine neoplasm (NEN). Histologically, the mass consisted of many disarranged small ducts without atypia embedded in abundant fibrous stroma and contained scant fatty tissue in the periphery, which was not identified on CT and MR images. There were no islets and peripheral nerves throughout the mass. Finally, it was pathologically diagnosed as a solid-type pancreatic hamartoma. Based on radiological-pathological correlation, it was considered that the abundant fibrous stroma and both the widely distributed myxomatous periductal stroma and scattered edematous stroma corresponded with delayed homogenous enhancement on CT/MR images and high ADC value, respectively. Although it is difficult to distinguish solid-type pancreatic hamartoma from other solid pancreatic neoplasms including hypovascular NEN on the basis of usual radiological findings, the high ADC value reflecting the specific pathology may be helpful for the differential diagnosis.

Solid Pseudopapillary Neoplasm of the Pancreas: A Case Report of a Rare Tumor Detected by Sonography

This case presentation describes a solid pseudopapillary neoplasm found in a young 41-year-old female. This mass was initially detected with sonography and later confirmed with an ultrasound-guided biopsy. The neoplasm was scheduled to be surgically resected, as a cure, which has a favorable long-term prognosis. This case provides information on the imaging characteristics and natural history of this benign neoplasm.

Differentiation of Solid Pseudopapillary Tumor and Non-Functional Neuroendocrine Tumors of the Pancreas Based on CT Delayed Imaging: A Propensity Score Analysis

PURPOSE

To evaluate the diagnostic performance of the delayed-phase difference between tumor and pancreas for differentiating solid pseudopapillary tumors (SPTs) from non-functional neuroendocrine tumors (NF-NETs) of the pancreas.

METHODS

This retrospective review included 148 consecutive patients with SPT and 98 consecutive patients with NF-NET confirmed by pathology. Patients with SPT and NF-NET were matched via propensity score matching (PSM). All patients underwent multidetector computed tomography (MDCT). For each patient, the delayed-phase difference between the tumor and pancreas was measured, and the performance of this variable was assessed based on its discriminative ability and clinical utility.

RESULTS

After PSM, 27 patients with SPT and 27 patients with NF-NET were included in the matched analysis. There were no statistically significant differences in clinical and CT characteristics between the resulting two groups (p > 0.05). The delayed-phase difference values between the tumor and pancreas were significantly lower in patients with SPT (median: -0.45; range: -2.05 to 0.73) than in patients with NF-NET (median: 0.71; range: -1.39 to 2.38). The delayed-phase difference between tumor and pancreas had a high diagnostic accuracy (area under the curve=0.88). The best cutoff point based on maximizing the sum of the sensitivity and specificity was -0.23 (sensitivity = 88.89%; specificity = 88.89%; accuracy = 0.89).

CONCLUSIONS

The delayed-phase difference between tumor and pancreas can accurately and noninvasively differentiate SPT from NF-NET.

Differentiation Between Solid Pseudopapillary Neoplasm of the Pancreas and Nonfunctional Pancreatic Neuroendocrine Neoplasm Using Endoscopic Ultrasound

OBJECTIVES

We investigated the utility of endoscopic ultrasound (EUS) for differentiating between solid pseudopapillary neoplasm of the pancreas (SPN) and pancreatic neuroendocrine neoplasm (PanNEN).

METHODS

A retrospective analysis was performed on 29 and 77 consecutive patients with pathologically proven SPN and nonfunctional PanNEN. In patients who underwent contrast-enhanced harmonic EUS (CH-EUS), lesions were classified into 3 vascular patterns (hypoechoic/isoechoic/hyperechoic), and the presence of "the alveolus nest sign," which we previously reported as a characteristic feature of SPN on CH-EUS, was also assessed.

RESULTS

Conventional EUS findings showed that calcification echoes were significantly more frequent in SPN lesions than in PanNEN lesions (19/29 [66%] vs 21/77 [27%], P = 0.001) as was internal isoechogenicity or hyperechogenicity (10/29 [34%] vs 11/77 [14%], P = 0.029). Contrast-enhanced harmonic EUS findings showed that SPN lesions more frequently had the isoechoic or hypoechoic vascular pattern, and significantly more frequently had the alveolus nest sign (18/25 [72%] vs 4/60 [7%], P < 0.001). In a multivariate analysis, the presence of the alveolus nest sign contributed the most to the SPN diagnosis (odds ratio, 70; 95% confidence interval, 6.2-786).

CONCLUSIONS

Endoscopic ultrasound, particularly the presence of the alveolus nest sign on CH-EUS, is useful for differentiating SPN from PanNEN.

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

BACKGROUND

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

CASE SUMMARY

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

CONCLUSION

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

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.

A limited panel of INSM1 and LEF1 immunostains accurately distinguishes between pancreatic neuroendocrine tumor and solid pseudopapillary neoplasm

Solid pseudopapillary neoplasm (SPN) and well differentiated pancreatic neuroendocrine tumor (PNET) can show significant cytomorphological overlap. In this study, we evaluated the role of INSM1 and LEF1 immunohistochemical stains in distinguishing between these two tumors. 22 SPN and 25 PNET surgically resected cases were stained for both INSM1 and LEF1. All the 22 cases of SPN showed strong and diffuse nuclear staining for LEF1 (in >95 % of tumor cells), while all 25 PNET were negative for LEF1. All 25 PNET cases were positive for INSM1 (moderate to strong intensity nuclear staining in >50 % of the tumor cells), while all 22 cases of SPN were negative for INSM1. The results of our study show that a limited panel comprising of INSM1 and LEF1 immunostains accurately distinguishes between SPN and PNET.

One size does not fit all for pancreatic cancers: A review on rare histologies and therapeutic approaches

Exocrine pancreatic neoplasms represent up to 95% of pancreatic cancers (PCs) and are widely recognized among the most lethal solid cancers, with a very poor 5-year survival rate of 5%-10%. The remaining < 5% of PCs are neuroendocrine tumors that are usually characterized by a better prognosis, with a median overall survival of 3.6 years. The most common type of PC is pancreatic ductal adenocarcinoma (PDAC), which accounts for roughly 85% of all exocrine PCs. However up to 10% of exocrine PCs have rare histotypes, which are still poorly understood. These subtypes can be distinguished from PDAC in terms of pathology, imaging, clinical presentation and prognosis. Additionally, due to their rarity, any knowledge regarding these specific histotypes is mostly based on case reports and a small series of retrospective analyses. Therefore, treatment strategies are generally deduced from those used for PDAC, even if these patients are often excluded or not clearly represented in clinical trials for PDAC. For these reasons, it is essential to collect as much information as possible on the management of PC, as assimilating it with PDAC may lead to the potential mistreatment of these patients. Here, we report the most significant literature regarding the epidemiology, typical presentation, possible treatment strategies, and prognosis of the most relevant histotypes among rare PCs.

A case of pancreatic hamartoma with characteristic radiological findings: radiological-pathological correlation

Pancreatic hamartoma is a rare benign tumor. Its preoperative diagnosis is challenging. We present a case of pancreatic hamartoma whose radiological-pathological correlation was evaluated in detail. A 53-year-old man was referred to our institution for diagnosis and treatment. Contrast-enhanced computed tomography (CT) and magnetic resonance image revealed a 3.5 cm long tumor arising from the head of the pancreas with cystic and solid components, the latter of which was gradually and inhomogeneously enhanced in the delayed phase. Fluorodeoxyglucose (FDG) positron emission tomography/CT revealed slight FDG uptake in the solid component. Histologically, a number of pancreatic lobule-like structures, which were mainly composed of aggregates of small ducts embedded in concentric fibrous stroma with no apparent islets or peripheral nerves, were observed in the solid component, whereas multiple dilated ducts were seen in the cystic region. The solid component also contained a narrow area of edematous fibrous stroma with low vessel density, which corresponded with the unenhanced part in the inhomogeneously enhanced solid component. There was no remarkable cytological atypia throughout the mass. A pathological diagnosis of pancreatic hamartoma was made. The radiological findings agree well with the pathological findings. When a pancreatic tumor is of the solid type, preoperatively diagnosing it as pancreatic hamartoma is not possible. However, when a pancreatic tumor with cystic and solid components is inhomogeneously enhanced in contrast-enhanced studies, a diagnosis of pancreatic hamartoma can be considered.

Magnetic resonance imaging in the assessment of pancreatic cancer with quantitative parameter extraction by means of dynamic contrast-enhanced magnetic resonance imaging, diffusion kurtosis imaging and intravoxel incoherent motion diffusion-weighted imaging

BACKGROUND

Despite great technical advances in imaging, such as multidetector computed tomography and magnetic resonance imaging (MRI), diagnosing pancreatic solid lesions correctly remains challenging, due to overlapping imaging features with benign lesions. We wanted to evaluate functional MRI to differentiate pancreatic tumors, peritumoral inflammatory tissue, and normal pancreatic parenchyma by means of dynamic contrast-enhanced MRI (DCE-MRI)-, diffusion kurtosis imaging (DKI)-, and intravoxel incoherent motion model (IVIM) diffusion-weighted imaging (DWI)-derived parameters.

METHODS

We retrospectively analyzed 24 patients, each with histopathological diagnosis of pancreatic tumor, and 24 patients without pancreatic lesions. Functional MRI was acquired using a 1.5 MR scanner. Peritumoral inflammatory tissue was assessed by drawing regions of interest on the tumor contours. DCE-MRI, IVIM and DKI parameters were extracted. Nonparametric tests and receiver operating characteristic (ROC) curves were calculated.

RESULTS

There were statistically significant differences in median values among the three groups observed by Kruskal-Wallis test for the DKI mean diffusivity (MD), IVIM perfusion fraction (fp) and IVIM tissue pure diffusivity (Dt). MD had the best results to discriminate normal pancreas plus peritumoral inflammatory tissue versus pancreatic tumor, to separate normal pancreatic parenchyma versus pancreatic tumor and to differentiate peritumoral inflammatory tissue versus pancreatic tumor, respectively, with an accuracy of 84%, 78%, 83% and area under ROC curve (AUC) of 0.85, 0.82, 0.89. The findings were statistically significant compared with those of other parameters (p value < 0.05 using McNemar's test). Instead, to discriminate normal pancreas versus peritumoral inflammatory tissue or pancreatic tumor and to differentiate normal pancreatic parenchyma versus peritumoral inflammatory tissue, there were no statistically significant differences between parameters' accuracy (p > 0.05 at McNemar's test).

CONCLUSIONS

Diffusion parameters, mainly MD by DKI, could be helpful for the differentiation of normal pancreatic parenchyma, perilesional inflammation, and pancreatic tumor.

Surgical Management of Solid Pseudopapillary Neoplasms of Pancreas: A Single-Center Experience of 60 Patients

BACKGROUND

Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare neoplasms, and the selection of surgical approaches is still under debate. The aim of this study was to analyze the clinicopathological characteristics and surgical outcomes of SPN patients and to compare the short-term and long-term outcomes between conventional operations and parenchyma-preserving operations.

METHODS

Patients who underwent pancreatic resection for SPNs between February 2010 and May 2019 in Fujian Medical University Union Hospital were identified. Clinicopathological details, perioperative data, and long-term follow-up results were retrospectively analyzed.

RESULTS

Sixty patients underwent surgical resection for SPNs during the study period: 48 females and 12 males. The mean age was 32.2 years. All patients underwent margin-negative surgical resection. The median follow-up period was 47 months (range: 3~118 months). One patient developed liver metastases 14 months after the operation and received local ablation therapy. All patients were alive during the follow-up. The incidence of postoperative pancreatic fistula was higher in the parenchyma-preserving surgery group than in the conventional surgery group (40.0 vs. 11.1%, p = 0.034). There was no significant difference in the tumor recurrence rate between the 2 groups. Eight (17.7%) and 6 patients (13.3%) in the conventional surgery group demonstrated endocrine and exocrine pancreatic insufficiency, respectively; furthermore, no patients in the parenchyma-preserving surgery group had endocrine or exocrine pancreatic insufficiency, but the incidences were not significantly different between the 2 groups.

CONCLUSIONS

Margin-negative surgical resection of SPNs yields a very low rate of tumor recurrence and excellent long-term survival.

An Unusual Presentation of a Solid Pseudopapillary Tumor of the Pancreas Mimicking Adenocarcinoma

Solid pseudopapillary tumors of the pancreas are rare and typically occur in young women. Compared with pancreatic adenocarcinoma, solid pseudopapillary tumors are characterized by notable indolent biological behavior associated with a favorable prognosis. Despite their large size, these tumors rarely metastasize. Even in cases of hepatic metastasis, most lesions are usually solitary in distribution and are amenable to resection. We report a case of a 55-year-old man with a small solid pseudopapillary tumor (≤3-cm diameter) mimicking a pancreatic adenocarcinoma, with multiple hepatic metastases. The diagnosis was confirmed by endoscopic ultrasound-guided fine-needle biopsy using a 22-G core needle. Unfortunately, rapid tumor progression led to patient mortality 5 months after diagnosis. To our knowledge, this is the first case report that describes a small solid pseudopapillary tumor of the pancreas with multiple hepatic metastasis and poor prognosis in a patient who was diagnosed with this condition at the time of initial diagnosis.

Clinical manifestations and multi-slice computed tomography characteristics of solid pseudopapillary neoplasms of the pancreas between males and females

Background

Solid-pseudo papillary neoplasms of pancreas (SPNP) are rare in men and are often misdiagnosed. This study aimed to analyze the clinical and multi-slice computer tomography (MSCT) features of patients with SPNP, and examine the differences between males and females.

Methods

In this retrospective cohort study, the clinical and imaging data of 29 patients with histolopathologically confirmed SPNP (seven males and 22 females) that underwent radical resection, and underwent preoperative MSCT at the First People’s Hospital of Lianyungang between August 2010 and December 2018 were collected. All MSCT images were reviewed by two radiologists; disagreements were ruled by a third one.

Results

The median age of the 29 patients with SPNP was 30 (range, 12–70) years. The male patients were older than the female patients [median, 56 (28–66) vs. 29 (12–70), P = 0.012]. The median tumor size was 3.9 (range, 2.0–6.4) cm in the male SPNP patients, which was significantly lower than the 7.0 (range, 4.6–14.6) cm in the female patients (P < 0.001). The calcification rate of the SPNP was significantly higher in male than in female patients (P = 0.013). The percentage of solid tumor was higher in males than in females (P = 0.036). Capsule, bleeding, and enhancement in the arterial and venous phases were not significantly different between the male and female patients (all P > 0.05).

Conclusion

The imaging features of male SPNP are distinct from those of female patients. In males with pancreatic lesions, MSCT generally shows relatively small lesions with higher percentages of solid components and calcification, with typical enhancement suggesting SPNP.

Differentiation of aggressive from non-aggressive pancreatic solid pseudopapillary neoplasms using computed tomography

PURPOSES

Microscopic aggressive behaviors may be related with the prognosis of solid pseudopapillary neoplasms (SPNs). In this study, we investigate computed tomography (CT) features and differential diagnosis of aggressive and non-aggressive SPNs in pancreas.

MATERIALS AND METHODS

122 patients with pathologically proven SPNs in pancreas were included. Patients' age, tumor site, texture, shape, margins, exophytic growth, capsule, calcification, hemorrhage, pancreatic duct dilatation or pancreatic parenchyma atrophy, peripancreatic infiltration or metastases, vascular encasement, and enhancement pattern were assessed. The diagnostic accuracy was analyzed by using the receiver operating characteristic curve (ROC).

RESULTS

There were 30 aggressive SPNs and 92 non-aggressive SPNs. Aggressive SPNs showed significantly higher frequencies of an ill-defined margin, patient age > 40.5 years, and tumor size < 42.1 mm, but lower frequencies of complete capsule, hemorrhage compared with non-aggressive SPNs (p < 0.05). Lack of complete capsule and age > 40.5 years were independent risk factors of aggressive SPNs (odd ratio 7.08 and 3.1, respectively). When we applied the two predictors in the logistic regression model, the area under the curve (AUC) was 0.77 with sensitivity of 86.7% and specificity of 55.4%.

CONCLUSION

Size less than 42.1 mm, lack of complete capsule, ill-defined, and absent bleeding are useful CT imaging features for predicating aggressive SPNs. Patient age > 40.5 years and lack of complete capsule showed acceptable diagnostic performance for discriminating aggressive from non-aggressive SPNs.

Management of solid pseudopapillary neoplasms of pancreas: A single center experience of 243 consecutive patients

BACKGROUND

Solid pseudopapillary neoplasm of the pancreas (SPN) is a rare neoplasm, which mainly affects young women. The aim of this study was to investigate the clinicopathological features and surgical management of SPNs in our institution.

METHODS

Patients who underwent surgery for a pathologically confirmed SPN in our institution between January 2008 and October 2018 were collected. Their clinical characteristics and survival associations were analyzed.

RESULTS

In total, 243 pathologically confirmed patients were analyzed in this study, including 181(74.5%)females and 62(25.5%) males. The mean age was 35.3 years old (range: 12-64 years old) with average tumor size of 4.83 cm (range: 0.8-16 cm). 239 patients underwent complete surgical resection. After median follow-up of 46 months (range: 10-118 months), four patients died due to tumor progression. All the other people were absent of local recurrence or distant metastasis.

CONCLUSIONS

SPN is a latent malignant tumor with excellent prognosis. Surgical resection is recommended even in the presence of liver metastasis. If possible, function-preserving surgery is advocated. High Ki67 index may predict the malignant potential and poor prognosis of SPNs.

Computed tomography and magnetic resonance imaging features of solid serous cystadenomas of the pancreas

Solid serous cystadenomas (SSC) of the pancreas are the rarest benign type of serous cystic neoplasms and are frequently misdiagnosed, resulting in unnecessary invasive surgical procedures. A retrospective study was performed to collect imaging features of SSC using computed tomography (CT) and magnetic resonance imaging. The clinical data and imaging study of 5 female patients with pathologically confirmed SSC (mean age, 44.2 years; range, 23-69 years) diagnosed between January 2006 and July 2017 were retrospectively analyzed. The imaging study was assessed by two experienced radiologists in consensus. All patients had tumors with a mean size of 2.3 cm (range, 1.5-3.2 cm; 4/5 lesions ≤3 cm). The tumors were located in the tail of pancreas in 3 cases and in the neck of the pancreas in 2 cases. The tumors were all well defined, with an ovoid and lobulated shape and fibrous capsules. Consequently, they presented as low density on unenhanced CT images, marked hyperintensity on T2-weighted images in 4 cases and slight hyperintensity in 1 case. However, they exhibited heterogeneous wash-in and wash-out enhancement in 2 cases and moderate and prolonged enhancement in 3 cases. The apparent diffusion coefficient (ADC) values of the lesions were >2×10^-3 mm²/sec. Therefore, a small tumor size, signal intensity on T2-weighted images, high ADC values, fibrous capsules and enhancement patterns may be indicative imaging features of SSCs.

Rare Solid Tumor of the Exocrine Pancreas: A Pictorial Review

Numerous other solid primary neoplasms may arise from the pancreas besides primary ductal adenocarcinomas and neuroendocrine tumors. Although diagnosis can be difficult because of the very low incidence of these tumors, knowledge of several, typical, epidemiologic, biological, and imaging features can help obtain a correct diagnosis. This pictorial review describes the features of solid rare primary pancreatic neoplasms on computed tomography and magnetic resonance imaging focusing on characteristics that can help radiologists differentiate them from classical forms of ductal pancreatic adenocarcinoma and neuroendocrine tumors. Cystic pancreatic neoplasms are beyond the scope of the current review.

Asymptomatic versus symptomatic solid pseudopapillary tumors of the pancreas: clinical and MDCT manifestations

BACKGROUND

To delineate the features of multi-detector computed tomography (MDCT) images and clinical characteristics of pancreatic solid pseudopapillary tumors (SPTs) of the pancreas in asymptomatic patients and compare these features and characteristics between asymptomatic and symptomatic patients.

METHODS

This work is a retrospective study approved by our institutional review board. MDCT images and clinical data of 109 patients with pathologically proven SPTs obtained from October 2008 to October 2016 were reviewed. Patients were categorized into two groups: asymptomatic patients and patients with symptomatic disease. Cases were reviewed to determine the reason for detection, intervention, shape, diameter, location, calcification, encapsulation, internal composition, CT attenuation, enhancement pattern, and tumor pathology. Clinical factors and imaging features were also compared between groups. Statistical analysis was performed using χ2 and t-tests.

RESULTS

Data from 49 asymptomatic and 60 symptomatic patients were collected. Asymptomatic SPTs were identified most frequently during routine health examination (18 patients, 36.7%), various screening purposes (12 patients, 24.5%), and traumatic injury (9 patients, 18.4%). Except for a smaller tumor size (5.8 cm in asymptomatic SPTs vs. 7.4 cm in symptomatic SPTs, P = 0.023), the clinical factors or imaging features of asymptomatic patients were very similar to those of symptomatic patients.

CONCLUSIONS

The current research is the first single-center study to characterize SPTs in asymptomatic patients. Asymptomatic SPTs are gradually being identified with greater frequency. Although generally smaller in size than that in symptomatic patients, an asymptomatic pancreatic mass with the typical imaging features of SPT may be found, the treatment for which is similar to that for symptomatic patients. Evaluating asymptomatic SPTs requires further systematic and multi-center trials.

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

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

Solid pseudopapillary neoplasm of the pancreas showing marked distal atrophy: A case report

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Solid pseudopapillary neoplasm with marked parenchymal atrophy of the distal pancreas.

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No acinar cells were observed, indicating exocrine dysfunction of atrophic parenchyma.

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The vestige of main pancreatic duct was observed in the distal atrophic pancreas.

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Central pancreatectomy without anastomosis of distal side of pancreas was performed.

Introduction

Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare neoplasm, affecting primarily young females. Because SPNs are of low-malignancy, they rarely obstruct the main pancreatic duct (MPD) and cause atrophy of the distal pancreas even if their tumor sizes are large.

Presentation of case

A 35-year-old female was referred to our hospital due to pancreatic tumor. Imaging findings showed the presence of well-defined round tumor in the body of the pancreas with 25-mm in diameter. The pancreas parenchyma distal to the tumor was markedly atrophic, and MPD dilatation was not observed. The lesion was diagnosed as SPN by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), and central pancreatectomy was performed. Intraoperative frozen section of the distal atrophic pancreas showed no evidence of acinar cells, indicating exocrine dysfunction. Therefore, we closed distal pancreas stump instead of reconstruction. In the distal atrophic parenchyma, scattered foci of islets of Langerhans and the vestige of dilated MPD were observed. She has shown neither endocrine nor exocrine insufficiency after surgery.

Discussion

SPNs are usually found without atrophic change of distal pancreas. To the best of our knowledge, this is the first report of SPN in which exocrine dysfunction of atrophic pancreas was demonstrated pathologically and central pancreatectomy without anastomosis of distal pancreas was chosen for the surgical treatment.

Conclusion

We reported a very rare case of SPN with marked distal parenchymal atrophy. We successfully performed central pancreatectomy without reconstruction.

Imaging and clinical features of xanthogranulomatous pancreatitis: an analysis of 10 cases at a single institution

PURPOSE

The purpose of the study was to investigate the imaging and clinical features of xanthogranulomatous pancreatitis (XGP).

METHODS

This retrospective series study included 10 patients with pathology-proven XGP. Two radiologists reviewed the computed tomography (CT) and magnetic resonance imaging (MRI) in consensus to determine the morphological features of XGP. The lesion enhancement pattern on dynamic contrast-enhanced scans and the MR signal intensity were also evaluated. Clinical data including symptoms, underlying pancreatic disease, and laboratory findings were reviewed.

RESULTS

Two XGP cases were of a solid type; six were of cystic type, and two were mixed type. XGP usually showed a lobulated contour (90%) and heterogeneous enhancement (100%), with lesion size varying from 2 to 11 cm. Perilesional infiltration was common (90%), but pancreatic duct dilatation was less frequent (30%). Cystic type XGP mostly had an irregular thick wall (83%). On dynamic contrast-enhanced CT/MRI, XGP enhanced progressively from arterial to portal or delayed phases. Lesions appeared hypointense on T1-weighted images (89%) and hyperintense on T2-weighted images (100%). All lesions appeared hyperintense on diffusion-weighted images, with the majority (78%) showing diffusion restriction on apparent diffusion coefficient maps. The patients often had abdominal pain (80%) and underlying pancreatic disease (80%), but mostly had normal or clinically insignificant laboratory findings.

CONCLUSIONS

XGP typically manifests as a clinically silent lobulated heterogeneous mass, with a progressive enhancement pattern and/or irregular thick wall, and diffusion restriction on CT/MRI. Awareness of the imaging and clinical features of XGP may help differentiate it from pancreatic neoplasms, thereby reducing unnecessary surgery.

Pancreas Ductal Adenocarcinoma and its Mimics: Review of Cross-sectional Imaging Findings for Differential Diagnosis

Ductal adenocarcinoma is the most common pancreatic neoplasm. A variety of pancreatic lesions mimic pancreas ductal adenocarcinoma (PDAC), such as high-grade neuroendocrine tumors, small solid pseudopapillary tumors, metastases, focal autoimmune pancreatitis, and groove pancreatitis. These occasionally look similar in images, but they have differential diagnosis points. Familiarity with the imaging features of PDAC and its mimics is paramount for correct diagnosis and management of patients. In this essay, we describe imaging findings of PDAC and its mimics for differential diagnosis.

Clinical update on the management of pseudopapillary tumor of pancreas

Solid pseudopapillary neoplasm (SPN) is a rare tumor with malignant potential which is generally located in the tail of pancreas. The prevalence of SPN has increased with widespread use of cross sectional imaging. SPN is often misdiagnosed due to nonspecific clinical presentation and accurate diagnosis is essential for optimal management. Endoscopic ultrasound-FNA with immunohistochemistry can help in preoperative diagnosis. Surgery is the treatment of choice and a successful R0 resection is curative. Overall, SPN has a good prognosis. This review article focuses on pathogenesis, diagnosis and management of SPN.

Prediction of malignancy and adverse outcome of solid pseudopapillary tumor of the pancreas

Since solid pseudopapillary tumor of the pancreas (SPTP) was officially classified by the World Health Organization in 1996, SPTP has recently received special attention in the literature. Studies have shown that SPTP is a heterogeneous tumor, with a small percentage of patients harboring aggressive behaviors. However, criteria for malignancy grade in SPTP have not been well established. The prognosis of SPTP is generally good, with cases having a chance for long-term survival even with recurrence and/or metastasis after surgical resection. The current American Joint Committee on Cancer/Union for International Cancer Control tumor, node, metastasis staging system is not specific to SPTP. The lack of a predictive staging classification that accurately describes the heterogeneity of this disease hinders meaningful research into optimal individualized therapy. Here we summarize and discuss the associated factors proposed for appraisal of the malignant potential and adverse outcome of SPTP.

Solid pseudopapillary neoplasm of pancreas: an unusual aetiology for haematochezia

Solid pseudopapillary neoplasm of the pancreas is a rare condition. It is mostly seen among young women, with abdominal pain as the presenting complaint. This is a case of a young woman who presented with haematochezia, and was found to have splenic vein thrombosis and left-sided portal hypertension as a result of mass lesion at the tail of the pancreas which was diagnosed as solid pseudopapillary neoplasm.

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.

Does Computed Tomography Have the Ability to Differentiate Aggressive From Nonaggressive Solid Pseudopapillary Neoplasm?

OBJECTIVE

The aim of the study was to assess the ability of contrast-enhanced computed tomography (CECT) to differentiate aggressive from nonaggressive solid pseudopapillary neoplasms (SPNs).

MATERIALS AND METHODS

Forty treatment-naive patients with pathologically proven pancreatic SPNs were included. Imaging characteristics were determined by consensus of 3 radiologists blinded to histopathologic aggressiveness. All patients underwent 4-phase CECT using a pancreatic protocol. The regions of interest of the tumor and the normal pancreas were documented on all phases. Lymph nodes were considered metastatic if greater than 1.0 cm in short-axis diameter.Fisher exact and Wilcoxon rank-sum tests were used to compare between aggressive and nonaggressive tumors.

RESULTS

No significant difference was noted between imaging covariates, such as internal hemorrhage, calcification, wall thickness perceptibility, vascular invasion, margins, cystic component, and pancreatic and biliary ductal dilation. Tumors with greater than 62.5 Hounsfield units and progressive enhancement during the delayed phase had aggressive characteristics (P = 0.03).

CONCLUSIONS

On delayed phase CECT, pathologically aggressive SPNs may show greater enhancement than nonaggressive SPNs.

Multiple solid pancreatic lesions: Prevalence and features of non-malignancies on dynamic enhanced CT

OBJECTIVE

To determine the prevalence of multiple solid pancreatic lesions on dynamic enhanced CT performed for suspected pancreatic diseases, and to identify CT features of non-malignancies.

METHODS

We investigated 8096 consecutive patients who underwent dynamic enhanced CT pancreas protocol at a tertiary center over 40 months. The final clinical /pathological diagnosis served as reference standard. The diagnostic accuracy of dynamic enhanced CT for non-malignancies was calculated. A univariate and multivariate analysis was conducted to identify features that predict non-malignancies.

RESULTS

Multiple solid pancreatic lesions were identified in 121 patients. The prevalence of non-malignancies was 19.8% (24/121). The most common non-malignancy was autoimmune pancreatitis (n = 21; 17.4%). Common lesions with malignant potential included neuroendocrine neoplasia (n = 62; 51.2%), ductal adenocarcinoma (n = 15; 12.4%), metastasis (n = 9; 7.4%), and lymphoma (n = 7; 5.8%). Dynamic enhanced CT had a sensitivity of 79.2% and a specificity of 92.8% for diagnosing non-malignancies. Elevated serum IgG4 level (p < 0.001), hypo-enhancement in arterial phase (p = 0.001), hyper-enhancement in equilibrium phase (p = 0.009) and location in both proximal and distal pancreas (p = 0.036) were predictors of non-malignancies, whereas pancreatic duct morphology and vascular invasion status were not.

CONCLUSION

Multiple solid pancreatic lesions were rare, with a wide spectrum. Dynamic enhanced CT provides clues for identifying non-malignancies.

Differentiation of benign and malignant solid pancreatic masses using magnetic resonance elastography with spin-echo echo planar imaging and three-dimensional inversion reconstruction: a prospective study

OBJECTIVES

To determine the diagnostic performance of MR elastography (MRE) and compare it with serum CA19-9 in differentiating malignant from benign pancreatic masses, with emphasis on differentiating between pancreatic ductal adenocarcinoma (PDAC) and mass-forming pancreatitis (MFP).

METHODS

We performed a prospective, consecutive, 24-month study in 85 patients with solid pancreatic masses confirmed by histopathologic examinations. The mass stiffness and stiffness ratio (calculated as the ratio of mass stiffness to the parenchymal stiffness) were assessed. The diagnostic accuracy was analysed by calculating the area under the ROC curve (AUROC).

RESULTS

The final diagnosis included 54 malignant tumours (43 patients with PDAC) and 31 benign masses (24 patients with MFP). The stiffness ratio showed better diagnostic performance than the mass stiffness and serum CA19-9 for the differentiation between malignant and benign masses (AUC: 0.912 vs. 0.845 vs. 0.702; P = 0.026, P < 0.001) and, specifically, between PDAC and MFP (AUC: 0.955 vs. 0.882 vs. 0.745; P = 0.026, P = 0.003). The sensitivity, specificity, and accuracy of stiffness ratio for the differentiation of PDAC and MFP were all higher than 0.9.

CONCLUSIONS

MRE presents an effective and quantitative strategy for non-invasive differentiation between PDAC and MFP based on their mechanical properties.

KEY POINTS

• 3D MRE is useful for calculating stiffness of solid pancreatic tumours. • Stiffness ratio outperformed stiffness and CA19-9 for differentiating PDAC from MFP. • Incorporation of 3D MRE into a standard MRI protocol is recommended.

Irreversible electroporation of locally advanced solid pseudopapillary carcinoma of the pancreas: A case report

Introduction

Solid pseudopapillary Carcinoma (SPC) is a rare pancreatic Tumor with variable, usually low, malignancy potential. Howewer, several SPC are associated with aggressive behavior, local vascular infiltration, organ invasion, distant metastasis, and can be unresectable. Irreversible Electroporation (IRE) is an emerging non-thermal ablation technique for the treatment of locally advanced pancreatic carcinoma. We report the results of four year disease-free follow-up in a case of locally advanced unresectable SPC treated with IRE.

Presentation of case

A 24-year female patient with SPC of the pancreas underwent IRE during laparotomy under general anesthesia with intubation. Computed Tomography (CT) showed complete tumor thrombosis of splenic vein, encasement of celiac artery and mesenteric vein. Six insertions of 3–4 electrodes per insertion were performed. One month-CT-control showed shrinkage of the tumor. 6 months-post-treatment imaging showed complete regression of the mass, patent Splenic/mesenteric veins, absence of local recurrence or distant metastasis. Post treatment CTs at 12-18-24-30-36-42-48 months follow-up confirmed absence of local or distant recurrence.

Discussion

Surgery is the first choice curative treatment of SPC. Howewer aggressive surgery (duodeno-pancreasectomy) in unresectable cases, may have a high risk of recurrences, morbidities and death, and bring concerns about endocrine and exocrine insufficiency in a young patient. In these cases, IRE could be a safe and effective alternative treatment and could realize, in selected cases, the condition for a radical surgery, and a bridge to R-0 resection.

Conclusions

IRE could represent an effective alternative therapy to surgery in local advanced, unresectable SPC.

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Solid pseudopapillary Carcinoma (SPC) is a rare pancreatic Tumor with possible local vascular infiltration, distant metastasis, and can be unresectable.

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Irreversible Electroporation (IRE) is a non-thermal ablation technique for locally advanced pancreatic neoplasms.

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There is no case of SPC treated with IRE reported in the literature.

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IRE could be a safe and effective alternative treatment and could be a bridge to R-0 resection.

Calcified pancreatic and peripancreatic neoplasms: spectrum of pathologies

A variety of pancreatic and peripancreatic neoplasms may contain calcifications. We present a review of common to uncommon pancreatic neoplasms that may contain calcifications to include ductal adenocarcinoma, pancreatic neuroendocrine tumors, serous cystadenomas, solid pseudopapillary tumors, intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, and lymphoepithelial cysts. In addition, duodenal mucinous adenocarcinoma can present as a peripancreatic mass that may contain calcification. Knowledge of the spectrum of calcification patterns can help the interpreting radiologist provide a meaningful differential.

Solid pseudopapillary tumor of the pancreas: clinical features and imaging findings

This study aimed to report clinical features and CT, MRI, PET/CT findings of solid pseudopapillary tumor (SPT) of the pancreas. Thirty-four patients with pathologically proven SPT were retrospectively reviewed. Most patients were asymptomatic. SPTs in male patients mainly appeared as solid and near solid tumors. Mixed tumors and cystic tumors had larger size than solid and near solid tumors. Solid tumors and solid part of mixed tumors were T2 hyperintense and T1 hypointense and had progressive enhancement. Four tumors (80%) showed markedly even or uneven ¹⁸F-FDG uptake. These characteristic features can help differentiate SPT from other pancreatic neoplasms.

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.

Image Findings of Solid Pseudopapillary Neoplasms of the Pancreas on Multiphasic Multidetector CT Scan-A Single Institute Experience from Southern India

Introduction

Solid Pseudopapillary Neoplasms (SPN) are uncommon pancreatic tumours and are slow growing with uncertain malignant potential, showing female preponderance. Postoperative prognosis is good and metastasis is rare.

Aim

To summarise the imaging and pathological features of seven cases of SPN in three years period, from January 2013 to January 2016.

Materials and Methods

In this retrospective study the imaging features of seven cases on triphasic multidetector Computed Tomogram (CT), a 16-slice scanner, were reviewed along with CT-guided Fine Needle Aspiration Cytology (FNAC) and histopathological examination. Statistics were expressed in terms of percentiles.

Results

All cases were female patients with an age range of 13-35 years (mean: 23.3 years). On CT assessment, the size of the tumours varied from 2.5-14 cm (mean: 5.3 cm). All these tumours were well capsulated and round to oval in shape. In four out of seven cases, the tumour was located in the tail of pancreas. All the solid enhancing portions showed moderate enhancement of at least 20-30 HU compared to unenhanced scan, on the other hand the cystic parts remained unenhanced with <5 HU variation in comparison to the plain scan. Histopathological examination exhibited characteristic poorly cohesive cuboidal cells arranged in papillaroid pattern having fine nuclear chromatin with nuclear grooves.

Conclusion

Solid pseudopapillary neoplasm is a high diagnostic possibility in case of a young female having pancreatic mass and needs to be evaluated with triphasic contrast enhanced CT scan, followed by FNAC and or histopathological examination.

Solid pseudopapillary tumor of the pancreas: Experience at a tertiary care centre of Northern India

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SPT is rare, but treatable pancreatic tumor.

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While clinical signs and symptoms are relatively nonspecific, characteristic findings on imaging and histology separate these tumors from the more malignant pancreatic tumors.

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The identification of a large bulky pancreatic tumour in a child or woman should raise suspicions of solid pseudopapillary tumour of the pancreas.

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Surgical excision offers the best chance for cure and should always be attempted irrespective of the magnitude of resection involved.

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Patients with SPT have an excellent prognosis after surgical excision. The prognosis is favorable even in the presence of distant metastasis.

Introduction

Solid pseudopapillary tumor (SPT) of the pancreas is rare, accounting for 0.13–2.7% of all pancreatic tumors. It is unique, has low malignant potential and predominantly affects young women. Radiological and pathological studies have revealed that the tumor is quite different from other pancreatic tumors. But the cell origin of SPT and tumorigenesis are still enigmatic. Abdominal mass is the most common presenting symptom. Due to the paucity of the number of cases, the natural history of the disease is not fully understood. This study was undertaken to examine the clinico-pathological characteristics of the disease and to evaluate the outcome of surgical intervention in a tertiary referral care centre.

Materials and methods

A retrospective analysis of all patients diagnosed and treated for SPN in our hospital over a period of 10 years (2005–2015) was carried out. A database of the characteristics of these patients was developed. In all, 11 patients were identified. A CT scan of the abdomen was performed in all the patients and the findings revealed a mass in the pancreas. The investigations performed included routine blood investigations, chest X-ray, CA-19-9 level and either an ultrasound or a CT Scan of the abdomen.

Results

During the time period of 10 years, of 349 patients with pancreatic malignancy admitted to our department, only 11 were diagnosed as having SPN (3.15%). Ten patients were women (90%) and one patient was a man (10%). The patients had a median age of 27.6 years (range 17–41). The most common symptoms were abdominal pain and dullness. Eight patients (72.7%) presented with abdominal pain or abdominal dullness and three patient (27%) were asymptomatic. All the 11 patients were taken up for surgery. Three patients underwent distal pancreatectomy with splenectomy, three patients underwent the total mass excision and one patient underwent total pancreatic resection. Three required extended distal pancreatectomy with splenectomy. One underwent spleen-preserving distal pancreatectomy.

Conclusion

SPT is rare, but treatable pancreatic tumor. While clinical signs and symptoms are relatively nonspecific, characteristic findings on imaging and histology separate these tumors from the more malignant pancreatic tumors. The prognosis is favorable even in the presence of distant metastasis. Although surgical resection is generally curative, a close follow-up is advised in order to diagnose a local recurrence or distant metastasis.

Pathology comparative study on the characteristic CT signs in solid pseudopapillary neoplasm of the pancreas

In order to analyze characteristic CT signs in the solid pseudopapillary tumor of the pancreas, a retrospective analysis was conducted on 49 patients with pseudopapillary tumor of the pancreas who where treated in Liaoning Cancer Hospital. All of the patients were confirmed by pathology, CT signs were analyzed and a pathology contrast was conducted. Furthermore, all cases had single lesions; 7 cases in the pancreatic head, 23 cases in the pancreatic body, 15 cases in the pancreatic body-tail and 4 cases in the pancreatic tail. The boundaries of the lesions were clear and the tumors, which may outline the pancreas, were composed of solid and polycystic parts. In addition, calcifications could be observed in the lesions and CT results revealed varying degrees of contrast enhancement of the solid components in the arterial phase, as well as a gradual contrast enhancement in the venous and delayed phase. Enhancement of capsule could be observed, and the enhancement region was observed in the solid part, no enhancement in cystic part.. In conclusion, CT manifestations of solid pseudopapillary tumors of the pancreas are specific, which is helpful to the diagnosis.

Enhancing pancreatic mass with normal serum CA19-9: key MDCT features to characterize pancreatic neuroendocrine tumours from its mimics

OBJECTIVES

To determine key MDCT features for characterizing pancreatic neuroendocrine tumours (PNET) from their mimics, which manifest as enhancing pancreatic mass with normal serum CA19-9 level.

METHODS

This retrospective study had institutional review board approval and informed consent was waived. Preoperative multiphase MDCT of 74 patients with enhancing pancreatic masses and normal serum CA19-9 levels were included. Surgical pathologies were PNET (n = 42), microcystic serous cystadenomas (m-SCN, n = 12) and solid pseudopapillary epithelial neoplasms (SPEN, n = 20). Two radiologists independently evaluated CT images with a checklist of findings. Frequencies of findings with each disease entity were compared. Diagnostic accuracy was assessed using the key MDCT features alone and in combination. Inter-observer agreement was evaluated.

RESULTS

The most common findings for PNET were mosaic morphological pattern (33/42, 78.6%) and enhancement peak in pancreatic arterial phase (PAP, 32/42, 76.2%), for m-SCN were honeycomb pattern (9/12, 75.0%) and enhancement peak in PAP (10/12, 83.3%) and for SPEN were melting icecream pattern (16/20, 80.0%) and hypo-enhancement in all phases (18/20, 90.0). Using a combination of morphological patterns and enhancement features, PNET was identified with 88% sensitivity and 81% specificity, m-SCN was identified with 83% sensitivity and 94% specificity, and SPEN was identified with 90% sensitivity and 91% specificity. Inter-observer agreement concerning CT findings was good to excellent (κ = 0.68 to 0.81, all p < 0.01).

CONCLUSIONS

Morphological features and enhancement patterns on MDCT are key features for characterizing enhancing pancreatic mass with normal serum CA19-9. PNET could be differentiated from its mimics with high accuracy.

Imaging Patterns of Intratumoral Calcification in the Abdominopelvic Cavity

Intratumoral calcification is one of the most noticeable of radiologic findings. It facilitates detection and provides information important for correctly diagnosing tumors. In the abdominopelvic cavity, a wide variety of tumors have calcifications with various imaging features, though the majority of such calcifications are dystrophic in nature. In this article, we classify the imaging patterns of intratumoral calcification according to number, location, and morphology. Then, we describe commonly-encountered abdominopelvic tumors containing typical calcification patterns, focusing on their differentiable characteristics using the imaging patterns of intratumoral calcification.

A solid pseudopapillary neoplasm of the pancreas in a man presenting with acute pancreatitis: A case report

INTRODUCTION

A solid pseudopapillary neoplasm (SPN) of the pancreas is rare neoplasm that occurs predominantly in young women. The clinical presentation of SPNs is nonspecific, but acute pancreatitis is rare in the reported literature.

PRESENTATION OF CASE

A 36-year-old man was referred to our hospital because of upper abdominal pain and elevation of serum amylase. A computed tomography (CT) scan showed swelling of the pancreas body and a poorly enhanced and indistinct mass in the pancreas body. He was diagnosed with acute pancreatitis. The symptom was improved with conservative treatment, but acute pancreatitis recurred twice during a period of 2 months. Magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) showed stenosis of the MPD adjacent to the mass. Distal pancreatectomy was performed because the mass in the pancreas body seemed to cause repeated acute pancreatitis and malignant pancreatic cancer could not be excluded. Immunohistochemically, a diagnosis of SPN of the pancreas was made from the resected specimen.

DISCUSSION

To the best our knowledge, only 6 cases have been reported in the literature concerning the SPN presenting with acute pancreatitis.

CONCLUSION

We report a man with a small SPN of the pancreas presenting with acute pancreatitis and mimicking pancreatic cancer. We should be aware that this rare pancreatic tumor can become a cause of acute pancreatitis.