Pancreatic tumors: emphasis on CT findings and pathologic classification

Imaging classification of pancreatic ductal adenocarcinoma with histological large duct pattern

OBJECTIVES

To investigate the imaging features of pancreatic ductal adenocarcinoma (PDAC) with histological large duct pattern.

METHODS

Our study included 37 patients (mean age, 66.5 years; 22 women) with surgically proven PDAC with histological large duct pattern, whose imaging features were classified into four types: Type I, solid mass; Type II, predominantly cystic mass with intracystic solid components; Type III, predominantly solid mass with intratumoral cysts; and Type IV, solid mass with peritumoral retention cysts or pseudocysts. Two radiologists independently analyzed both CT and MRI images for the morphological type, presence of abrupt main pancreatic duct (MPD) cutoff, adjacent vascular invasion, diffusion restriction, and reached consensus.

RESULTS

On CT, 26 patients (70.3%) had Type I tumors, five (13.5%) had Type II, three (8.1%) had Type III, and three (8.1%) had Type IV. Among the 26 patients with Type I tumors on CT, 16 had tumors with multiple intratumoral cysts within the solid mass on MRI and were subsequently classified as Type III. Accordingly, 10 patients (27.0%) were classified as Type I, five (13.5%) as Type II, 19 (51.7%) as Type III, and three (8.1%) as Type IV on MRI. Of the 37 patients, 27 (73.0%) had an abrupt MPD cutoff, 15 (40.5%) had adjacent vascular invasion, and 25 (67.6%) had diffusion restriction on MRI.

CONCLUSIONS

Predominantly solid pancreatic masses with small intratumoral cysts visualized on MRI may be a characteristic imaging finding of PDAC with histological large duct pattern, and differentiate it from conventional PDAC or other cystic pancreatic tumors.

CLINICAL RELEVANCE STATEMENT

Radiologists should be familiar with the various imaging features of PDAC with histological large duct pattern and should be aware that it may mimic other solid or cystic tumors of the pancreas.

KEY POINTS

Imaging features of pancreatic ductal adenocarcinoma with histological large duct pattern can be classified into four types. This pathology more frequently appears as a predominantly solid mass with intratumoral cysts on MRI than on CT. Adding MRI to CT may help identify pancreatic ductal adenocarcinoma with histological large duct pattern.

Cystic ductal adenocarcinoma of pancreas complicated with neuroendocrine tumor: A case report and review of literature

BACKGROUND

Difficulties in making an accurate preoperative diagnosis of cystic pancreatic lesions pose a challenge for radiologists. It would be helpful to report rare cases and review the literature.

CASE SUMMARY

In the present report, a case of a patient with a pancreatic cystic lesion initially misdiagnosed as a pseudocyst by radiologist was documented, which was later pathologically confirmed as pancreatic ductal adenocarcinoma with neuroendocrine tumor. However, subsequent literature review yielded no previous reports of pancreatic ductal adenocarcinoma with neuroendocrine tumors and cystic lesions. Therefore, literature on the imaging diagnosis of pancreatic cystic lesions was instead reviewed and discussed.

CONCLUSION

Careful evaluation of the characteristics revealed by multimodal imaging techniques, medical history, laboratory examination data and follow-up observations, is critical to the diagnosis and treatment of pancreatic cystic disease. We provide valuable insights into the diagnosis of pancreatic cystic disease through a rare case report and literature review.

Imaging of pancreatic serous cystadenoma and common imitators

Pancreatic cystic neoplasms are lesions comprised of cystic components that show different biological behaviors, epidemiology, clinical manifestations, imaging features, and malignant potential and management. Benign cystic neoplasms include serous cystic neoplasms (SCAs). Other pancreatic cystic lesions have malignant potential, such as intraductal papillary mucinous neoplasms and mucinous cystic neoplasms. SCAs can be divided into microcystic (classic appearance), honeycomb, oligocystic/macrocystic, and solid patterns based on imaging appearance. They are usually solitary but may be multiple in von Hippel-Lindau disease, which may depict disseminated involvement. The variable appearances of SCAs can mimic other types of pancreatic cystic lesions, and cross-sectional imaging plays an important role in their differential diagnosis. Endoscopic ultrasonography has helped in improving diagnostic accuracy of pancreatic cystic lesions by guiding tissue sampling (biopsy) or cyst fluid analysis. Immunohistochemistry and newer techniques such as radiomics have shown improved performance for preoperatively discriminating SCAs and their mimickers.

Poorly Controlled New-Onset Diabetes Mellitus and Other Atypical Signs as an Early Sign of Pancreatic Adenocarcinoma

A 50-year-old man presented with poorly controlled new-onset diabetes mellitus. Six months after diagnosis, episodes of intense abdominal pain with vomiting appeared. Abdominal CT revealed signs of acute pancreatitis with structural changes in the pseudocysts. In the absence of biliary lithiasis or a toxic etiology of acute pancreatitis, the patient progressed unfavorably with increased abdominal pain and fever. Control imaging tests (two and 10 months later) showed the evolution of phlegmonous/necrotic collections, together with portal vein thrombosis and splenomegaly. Given the suggestive signs of possible occult malignancy, such as portal thrombosis, histological analysis of the ascitic fluid revealed a pancreatic adenocarcinoma. Despite the initiation of chemotherapy, the patient died 12 months after diagnosis.

Pancreatic colloid adenocarcinoma arising from intraductal papillary mucinous neoplasm: Radiologic-pathologic correlation with cinematic rendering

Intraductal papillary mucinous neoplasms (IPMN) of the pancreas have the potential for malignant progression into adenocarcinoma. Colloid or mucinous non-cystic carcinoma of the pancreas is an uncommon variant neoplasm that can arise within an intestinal type IPMN and have a relatively improved prognosis but may mimic the more lethal tubular or ductal adenocarcinoma. Colloid carcinoma is an infiltrating ductal epithelial neoplasm containing primarily extracellular stromal mucin pools and scant amount of centrally floating neoplastic cells. While several reports have evaluated the unique pathologic and immunohistochemical profile of colloid carcinomas, there has been limited radiologic-pathologic correlation in the literature. We report a case of an 83-year-old female who presented for evaluation of slowly progressive abdominal pain and was found to have colloid carcinoma arising from an IPMN. This is one of the first reports to correlate the multimodality radiology including cinematic rendering (CR) and histopathology features associated with this tumor. An enhanced understanding of the correlation between imaging appearance and specific histopathologic findings may aid in the early recognition and treatment of this rare neoplasm. Emphasis is placed on CR as this may help guide surgical management.

Prognostic value of preoperative enhanced computed tomography as a quantitative imaging biomarker in pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies with high mortality and short survival time. Computed tomography (CT) plays an important role in the diagnosis, staging and treatment of pancreatic tumour. Pancreatic cancer generally shows a low enhancement pattern compared with normal pancreatic tissue.

AIM

To analyse whether preoperative enhanced CT could be used to predict postoperative overall survival in patients with PDAC.

METHODS

Sixty-seven patients with PDAC undergoing pancreatic resection were enrolled retrospectively. All patients underwent preoperative unenhanced and enhanced CT examination, the CT values of which were measured. The ratio of the preoperative CT value increase from the nonenhancement phase to the portal venous phase between pancreatic tumour and normal pancreatic tissue was calculated. The cut-off value of ratios was obtained by the receiver operating characteristic (ROC) curve of the tumour relative enhancement ratio (TRER), according to which patients were divided into low- and high-enhancement groups. Univariate and multivariate analyses were performed using Cox regression based on TRER grouping. Finally, the correlation between TRER and clinicopathological characteristics was analysed.

RESULTS

The area under the curve of the ROC curve was 0.768 (P < 0.05), and the cut-off value of the ROC curve was calculated as 0.7. TRER ≤ 0.7 was defined as the low-enhancement group, and TRER > 0.7 was defined as the high-enhancement group. According to the TRER grouping, the Kaplan-Meier survival curve analysis results showed that the median survival (10.0 mo) with TRER ≤ 0.7 was significantly shorter than that (22.0 mo) with TRER > 0.7 (P < 0.05). In the univariate and multivariate analyses, the prognosis of patients with TRER ≤ 0.7 was significantly worse than that of patients with TRER > 0.7 (P < 0.05). Our results demonstrated that patients in the low TRER group were more likely to have higher American Joint Committee on Cancer stage, tumour stage and lymph node stage (all P < 0.05), and TRER was significantly negatively correlated with tumour size (P < 0.05).

CONCLUSION

TRER ≤ 0.7 in patients with PDAC may represent a tumour with higher clinical stage and result in a shorter overall survival.

3D Virtual Pancreatography

We present 3D virtual pancreatography (VP), a novel visualization procedure and application for non-invasive diagnosis and classification of pancreatic lesions, the precursors of pancreatic cancer. Currently, non-invasive screening of patients is performed through visual inspection of 2D axis-aligned CT images, though the relevant features are often not clearly visible nor automatically detected. VP is an end-to-end visual diagnosis system that includes: A machine learning based automatic segmentation of the pancreatic gland and the lesions, a semi-automatic approach to extract the primary pancreatic duct, a machine learning based automatic classification of lesions into four prominent types, and specialized 3D and 2D exploratory visualizations of the pancreas, lesions and surrounding anatomy. We combine volume rendering with pancreas- and lesion-centric visualizations and measurements for effective diagnosis. We designed VP through close collaboration and feedback from expert radiologists, and evaluated it on multiple real-world CT datasets with various pancreatic lesions and case studies examined by the expert radiologists.

Pancreatic Collision Tumor of Desmoid-Type Fibromatosis and Mucinous Cystic Neoplasm: A Case Report

Pancreatic collision tumors are rare neoplasm, and cases consisting of ductal adenocarcinoma with a neuroendocrine tumor, intraductal papillary mucinous neoplasm with a neuroendocrine tumor, and solid pseudopapillary neoplasm with a neuroendocrine tumor have been reported. We report a case of a rapidly growing pancreatic collision tumor consisting of desmoidtype fibromatosis and mucinous cystic neoplasm in a 30-year-old pregnant female. To the best of our knowledge, this is the first reported case of a pancreatic collision tumor consisting of desmoid-type fibromatosis and mucinous cystic neoplasm.

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.

Comparative Diagnostic Evaluation with Contrast-Enhanced Ultrasound, Computed Tomography and Magnetic Resonance Imaging in Patients with Pancreatic Cystic Neoplasms

Purpose

The purpose of our study was to evaluate the role of contrast-enhanced ultrasound (CEUS) with magnetic resonance imaging (MRI) and computed tomography (CT) in the pathological diagnosis of pancreatic cystic neoplasms (PCNs).

Methods

A total of 90 patients (66 women, 24 men) aged 18–71 years were studied prospectively. CEUS was performed in all patients, whereas MRI was performed in 85 patients and CT in 69 patients. We analyzed the sensitivity and accuracy of these three imaging modalities to diagnose the PCNs. Neoplasm size, location, shape, intralesional mural nodules, septa and duct dilatation were also assessed by different radiologists.

Results

There were no significant differences in sensitivity for discriminating PCNs from pancreatic cystic lesions between CEUS and MRI (p=0.614) or between CEUS and CT (p=0.479). The diagnostic accuracy of CEUS for classifying PCNs was 64.4% (58/90), which was higher than that of CT (53.6%, 37/69, P=0.017), and lower than that of MRI (70.6%, 60/85, p=0.791). Regarding tumor size for lesions larger than 3 cm, CEUS was superior to CT in differentiating the specific type of PCN (p=0.041), and CEUS had the same value as MRI (p=0.774). Furthermore, CEUS is valuable for precisely characterizing internal structures, for instance, septa (p=0.003, compared with CT; p=0.443, compared with MRI) and nodules (p= 0.018, compared with CT; p=0.033, compared with MRI). The number of septa (p=0.033) and cyst morphology (p=0.016) were meaningful indicators in differentiating serous and mucinous adenoma. There was no significant difference in evaluating size and detecting duct dilatation among the three imaging methods.

Conclusion

CEUS compares favorably with MRI in displaying the inner structure of PCNs and offers advantages over CT. CEUS can contribute in an important way to the diagnosis of pancreatic cystic neoplasms.

A Prospective Study on Contrast-Enhanced Endoscopic Ultrasound for Differential Diagnosis of Pancreatic Cystic Neoplasms

BACKGROUND AND AIMS

To determine the value of contrast-enhanced endoscopic ultrasound (CE-EUS) for differentiation of pancreatic cystic neoplasms (PCNs).

METHODS

From April 2015 to December 2017, 82 patients were enrolled in this study. All patients were confirmed to have PCNs by surgical pathology. Prior to surgery, all patients underwent fundamental B-mode EUS (FB-EUS) and CE-EUS, 65 of whom underwent computed tomography (CT) and 71 of whom underwent magnetic resonance imaging (MRI). The enhanced mode data of PCNs were recorded. The diagnostic accuracy of CE-EUS in classifying PCNs was compared with that of CT, MRI and FB-EUS. The ability of CE-EUS to identify PCNs was evaluated by comparing the enhanced mode of PCNs.

RESULTS

There was a significant difference between benign and malignant lesions in enhanced mode (P = 0.017). The enhanced modes of benign lesions were mostly type II and type III, while those of malignant lesions were type 0, type I, and type IV. The sensitivity, specificity, and accuracy of type 0, type I, and type IV enhanced mode as the diagnostic criterion for malignant lesions were 80%, 65.3%, and 67.1%, respectively. CE-EUS demonstrated greater accuracy in identifying PCNs than did CT, MRI, and FB-EUS (CE-EUS vs. CT: 92.3% vs. 76.9%; CE-EUS vs. MRI: 93.0% vs. 78.9%; CE-EUS vs. FB-EUS: 92.7% vs. 84.2%).

CONCLUSION

Compared with CT, MRI, and FB-EUS, CE-EUS is better at differentiating PCNs. CE-EUS is expected to be another important imaging technique for the diagnosis of PCNs.

Metastatic mucinous cystadenocarcinoma of the pancreas presenting as intractable back pain

An 85-year-old woman presented to the emergency department for evaluation of gradually worsening upper back pain of 3 weeks' duration. Her pain radiated down her right arm and was associated with right arm weakness. She reported visiting pain medicine specialists who administered steroid and lidocaine injections, which failed to improve her symptoms. Initial CT of her chest revealed a large lytic lesion within her posterior right fourth rib extending into her T4 vertebral body. The primary malignancy, a mucinous cystadenocarcinoma of the pancreas, was later found on a CT of the abdomen. The patient was also found to have multiple pulmonary, hepatic and lymphatic metastases from the pancreatic primary tumour.

Pancreas ductal adenocarcinoma with cystic features on cross-sectional imaging: radiologic-pathologic correlation

Most pancreatic ductal adenocarcinomas (PDAs) show solid growth pattern, but ductal adenocarcinomas may demonstrate intratumoral cystic appearance or accompany peritumoral non-neoplastic cystic lesions, thus mimicking cystic pancreatic tumors on imaging studies. The histopathologic findings for PDA with cystic feature are divided into neoplastic and non-neoplastic cysts. Neoplastic cystic changes include large-duct type cysts (microcystic appearance), neoplastic mucin cysts (macrocystic appearance), colloid carcinomas (mucinous noncystic adenocarcinomas), and degenerative cystic change usually caused by hemorrhagic necrosis of tumor. Non-neoplastic cystic changes include retention cysts caused by ductal obstruction and pseudocysts caused by tumor-associated pancreatitis. Depending on the presence, size, number, and configuration of cystic changes, PDA should be differentiated from various types of cystic neoplasms. This pictorial essay provides histopathologic classification of PDAs with cystic features along with the corresponding cross-sectional imaging findings, and their differential diagnosis.

Hemosuccus pancreaticus from superior mesenteric artery pseudoaneurysm within perceived pancreatic mass

Bleeding from the pancreatic duct is a rare source of gastrointestinal hemorrhage and is referred to as hemosuccus pancreaticus. Often a result of pseudoaneurysm formation from chronic pancreatitis, hemosuccus pancreaticus is a difficult diagnosis due to its peculiar clinical presentation. This is a case of a 51-year-old male with a history of chronic pancreatitis, who initially presented with a pancreatic mass found on CT scan. The mass was found to be inconclusive for malignancy on endoscopic ultrasound-guided fine needle aspiration. The patient subsequently was lost to follow-up and returned with melena and evidence of a superior mesenteric pseudoaneurysm in the previous mass on CT angiography. The pseudoaneurysm was successfully treated with endovascular embolization. Diagnosis of hemosuccus pancreaticus can be challenging due to the intermittent nature of hemorrhage and the variable clinical presentation-which initially appeared as a pancreatic neoplasm in our patient. Repeat imaging and angiography are invaluable for both the diagnosis and treatment of gastrointestinal bleeding from an unknown source in the setting of chronic pancreatitis.

Diagnostic performance of contrast-enhanced ultrasound for pancreatic neoplasms: A systematic review and meta-analysis

BACKGROUND

Early diagnosis of pancreatic cancer is essential to optimize treatment strategies.

OBJECTIVES

To evaluate the diagnostic performance of contrast-enhanced ultrasound for benign and malignant pancreatic neoplasms.

DATA SOURCES

Pubmed, Embase, Web of Science, and Cochrane Library databases.

STUDY ELIGIBILITY CRITERIA

Retrospective or prospective studies.

PARTICIPANTS

Patients with a confirmed diagnosis of benign and malignant pancreatic neoplasms.

INTERVENTION

Contrast-enhanced ultrasound.

STUDY APPRAISAL AND SYNTHESIS

Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic risk ratio, and corresponding 95% confidence intervals; summary receiver operating characteristic (SROC) curve; a Fagan nomogram.

RESULTS

Ten studies involving 641 patients were included. Pooled sensitivity, specificity, and positive and negative predictive values were 91% (95% CI: 87%, 93%), 87% (95% CI: 78%, 93%), 7.2 (95% CI: 4.3, 12.3), and 0.11 (95% CI: 0.08, 0.15), respectively; and the odds ratio for diagnosis was 67 (95% CI: 34, 113). Contrast-enhanced ultrasound had good diagnostic ability and accuracy. Pre- and post-test probability of disease was 50% and 88%, respectively, when the positive likelihood ratio was 7.

CONCLUSION

Contrast-enhanced ultrasound can be used for qualitative diagnosis of benign and malignant pancreatic neoplasms.

IMPLICATIONS OF KEY FINDINGS

CEUS should be considered as an important imaging tool for the characterization of pancreatic tumors.

SYSTEMATIC REVIEW REGISTRATION NUMBER

CRD42017070434 (PROSPERO).

Classification of Pancreatic Cysts in Computed Tomography Images Using a Random Forest and Convolutional Neural Network Ensemble

There are many different types of pancreatic cysts. These range from completely benign to malignant, and identifying the exact cyst type can be challenging in clinical practice. This work describes an automatic classification algorithm that classifies the four most common types of pancreatic cysts using computed tomography images. The proposed approach utilizes the general demographic information about a patient as well as the imaging appearance of the cyst. It is based on a Bayesian combination of the random forest classifier, which learns subclass-specific demographic, intensity, and shape features, and a new convolutional neural network that relies on the fine texture information. Quantitative assessment of the proposed method was performed using a 10-fold cross validation on 134 patients and reported a classification accuracy of 83.6%.

Comparison of endoscopic ultrasound, computed tomography and magnetic resonance imaging in assessment of detailed structures of pancreatic cystic neoplasms

AIM

To evaluate the advantages of endoscopic ultrasound (EUS) in the assessment of detailed structures of pancreatic cystic neoplasms (PCNs) compared to computed tomography (CT) and magnetic resonance imaging (MRI).

METHODS

All patients with indeterminate PCNs underwent CT, MRI, and EUS. The detailed information, including size, number, the presence of a papilla/nodule, the presence of a septum, and the morphology of the pancreatic duct of PCNs were compared among the three imaging modalities. The size of each PCN was determined using the largest diameter measured. A cyst consisting of several small cysts was referred to as a mother-daughter cyst. Disagreement among the three imaging modalities regarding the total number of mother cysts resulted in the assumption that the correct number was the one in which the majority of imaging modalities indicated.

RESULTS

A total of 52 females and 16 males were evaluated. The median size of the cysts was 42.5 mm by EUS, 42.0 mm by CT and 38.0 mm by MRI; there was no significant difference in size as assessed among the three imaging techniques. The diagnostic sensitivity and ability of EUS to classify PCNs were 98.5% (67/68) and 92.6% (63/68), respectively. These percentages were higher than those of CT (73.1%, P < 0.001; 17.1%, P < 0.001) and MRI (81.3%, P = 0.001; 20.3%, P < 0.001). EUS was also able to better assess the number of daughter cysts in mother cysts than CT (P = 0.003); however, there was no significant difference between EUS and MRI in assessing mother-daughter cysts (P = 0.254). The papilla/nodule detection rate by EUS was 35.3% (24/68), much higher than those by CT (5.8%, 3/52) and MRI (6.3%, 4/64). The detection rate of the septum by EUS was 60.3% (41/68), which was higher than those by CT (34.6%, 18/52) and by MRI (46.9%, 30/64); the difference between EUS and CT was significant (P = 0.02). The rate of visualizing the pancreatic duct using EUS was 100%, whereas using CT and MRI it was less than 10%.

CONCLUSION

EUS helps visualize the detailed structures of PCNs and has many advantages over CT and MRI. EUS is valuable in the diagnosis and assessment of PCNs.

Imaging modalities for characterising focal pancreatic lesions

BACKGROUND

Increasing numbers of incidental pancreatic lesions are being detected each year. Accurate characterisation of pancreatic lesions into benign, precancerous, and cancer masses is crucial in deciding whether to use treatment or surveillance. Distinguishing benign lesions from precancerous and cancerous lesions can prevent patients from undergoing unnecessary major surgery. Despite the importance of accurately classifying pancreatic lesions, there is no clear algorithm for management of focal pancreatic lesions.

OBJECTIVES

To determine and compare the diagnostic accuracy of various imaging modalities in detecting cancerous and precancerous lesions in people with focal pancreatic lesions.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, and Science Citation Index until 19 July 2016. We searched the references of included studies to identify further studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We planned to include studies reporting cross-sectional information on the index test (CT (computed tomography), MRI (magnetic resonance imaging), PET (positron emission tomography), EUS (endoscopic ultrasound), EUS elastography, and EUS-guided biopsy or FNA (fine-needle aspiration)) and reference standard (confirmation of the nature of the lesion was obtained by histopathological examination of the entire lesion by surgical excision, or histopathological examination for confirmation of precancer or cancer by biopsy and clinical follow-up of at least six months in people with negative index tests) in people with pancreatic lesions irrespective of language or publication status or whether the data were collected prospectively or retrospectively.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the references to identify relevant studies and extracted the data. We planned to use the bivariate analysis to calculate the summary sensitivity and specificity with their 95% confidence intervals and the hierarchical summary receiver operating characteristic (HSROC) to compare the tests and assess heterogeneity, but used simpler models (such as univariate random-effects model and univariate fixed-effect model) for combining studies when appropriate because of the sparse data. We were unable to compare the diagnostic performance of the tests using formal statistical methods because of sparse data.

MAIN RESULTS

We included 54 studies involving a total of 3,196 participants evaluating the diagnostic accuracy of various index tests. In these 54 studies, eight different target conditions were identified with different final diagnoses constituting benign, precancerous, and cancerous lesions. None of the studies was of high methodological quality. None of the comparisons in which single studies were included was of sufficiently high methodological quality to warrant highlighting of the results. For differentiation of cancerous lesions from benign or precancerous lesions, we identified only one study per index test. The second analysis, of studies differentiating cancerous versus benign lesions, provided three tests in which meta-analysis could be performed. The sensitivities and specificities for diagnosing cancer were: EUS-FNA: sensitivity 0.79 (95% confidence interval (CI) 0.07 to 1.00), specificity 1.00 (95% CI 0.91 to 1.00); EUS: sensitivity 0.95 (95% CI 0.84 to 0.99), specificity 0.53 (95% CI 0.31 to 0.74); PET: sensitivity 0.92 (95% CI 0.80 to 0.97), specificity 0.65 (95% CI 0.39 to 0.84). The third analysis, of studies differentiating precancerous or cancerous lesions from benign lesions, only provided one test (EUS-FNA) in which meta-analysis was performed. EUS-FNA had moderate sensitivity for diagnosing precancerous or cancerous lesions (sensitivity 0.73 (95% CI 0.01 to 1.00) and high specificity 0.94 (95% CI 0.15 to 1.00), the extremely wide confidence intervals reflecting the heterogeneity between the studies). The fourth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (dysplasia) provided three tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing invasive carcinoma were: CT: sensitivity 0.72 (95% CI 0.50 to 0.87), specificity 0.92 (95% CI 0.81 to 0.97); EUS: sensitivity 0.78 (95% CI 0.44 to 0.94), specificity 0.91 (95% CI 0.61 to 0.98); EUS-FNA: sensitivity 0.66 (95% CI 0.03 to 0.99), specificity 0.92 (95% CI 0.73 to 0.98). The fifth analysis, of studies differentiating cancerous (high-grade dysplasia or invasive carcinoma) versus precancerous (low- or intermediate-grade dysplasia) provided six tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing cancer (high-grade dysplasia or invasive carcinoma) were: CT: sensitivity 0.87 (95% CI 0.00 to 1.00), specificity 0.96 (95% CI 0.00 to 1.00); EUS: sensitivity 0.86 (95% CI 0.74 to 0.92), specificity 0.91 (95% CI 0.83 to 0.96); EUS-FNA: sensitivity 0.47 (95% CI 0.24 to 0.70), specificity 0.91 (95% CI 0.32 to 1.00); EUS-FNA carcinoembryonic antigen 200 ng/mL: sensitivity 0.58 (95% CI 0.28 to 0.83), specificity 0.51 (95% CI 0.19 to 0.81); MRI: sensitivity 0.69 (95% CI 0.44 to 0.86), specificity 0.93 (95% CI 0.43 to 1.00); PET: sensitivity 0.90 (95% CI 0.79 to 0.96), specificity 0.94 (95% CI 0.81 to 0.99). The sixth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (low-grade dysplasia) provided no tests in which meta-analysis was performed. The seventh analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) provided two tests in which meta-analysis was performed. The sensitivity and specificity for diagnosing cancer were: CT: sensitivity 0.83 (95% CI 0.68 to 0.92), specificity 0.83 (95% CI 0.64 to 0.93) and MRI: sensitivity 0.80 (95% CI 0.58 to 0.92), specificity 0.81 (95% CI 0.53 to 0.95), respectively. The eighth analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) or benign lesions provided no test in which meta-analysis was performed.There were no major alterations in the subgroup analysis of cystic pancreatic focal lesions (42 studies; 2086 participants). None of the included studies evaluated EUS elastography or sequential testing.

AUTHORS' CONCLUSIONS

We were unable to arrive at any firm conclusions because of the differences in the way that study authors classified focal pancreatic lesions into cancerous, precancerous, and benign lesions; the inclusion of few studies with wide confidence intervals for each comparison; poor methodological quality in the studies; and heterogeneity in the estimates within comparisons.

Solid pseudopapillary tumor of pancreas: A lesser known entity-diagnosis and pitfalls: A case report

Solid pseudopapillary tumor (SPT) is a rare pancreatic neoplasm with a reported incidence of 0.1% to 2.7% of all pancreatic tumors. Because radiological presentation of pancreatic tumors is quite overlapping, distinctive features in fine needle aspiration cytology (FNAC) helps in its diagnosis preoperatively. Being a low-grade malignancy presenting predominantly in young females, correct preoperative diagnosis minimizes the need of extensive surgery. SPT carries good prognosis without any adjuvant chemotherapy/radiotherapy in most cases, even in the presence of metastatic disease. On the other hand, aggressive surgical resection is required for ductal adenocarcinoma which is more common pancreatic tumor (90%). We report here a case of a 49-year-old female diagnosed as SPT. The importance of the need for the radiologist, pathologist, and surgeon to be familiar with SPT is highlighted so that it is more often diagnosed as there are significant therapeutic and prognostic implications.

Diagnosis, Preoperative Evaluation, and Assessment of Resectability of Pancreatic and Periampullary Cancer

Periampullary region encircles a radius of 2 cm around the ampulla of Vater; accordingly, four distinct neoplasias with overlapping imaging features originate in the region. Each of these lesions has a different long-term prognosis; hence, imaging evaluation to characterize the lesion is important. Further certain specific features pertaining to the vascular invasion and systemic spread may decide about the treatment as well as surgical approach. An understanding of the advances in imaging and image processing technology as well as in the methods of image acquisition, for the purpose, is quite relevant towards etching out a rational pre-treatment evaluation protocol. Further, an evidence-based decision as to the choice of optimum modality for answering specific clinical question is of prime importance in achieving a reasonable post-treatment outcome. Pancreatic adenocarcinoma is the fourth most common cancer and a malignancy with one of the least 5-year survival rates (ranging from 6.8 to 15 % depending on peripancreatic extensions, dropping to 1.8 % for metastatic disease). A survival rate of 15-27 % can be achieved if the lesion is resectable but unfortunately, only 10-15 % of patients are eligible for resection. Cystic tumors of pancreas are a rarer variety of pancreatic neoplasia (5-15 % of pancreatic cysts and 1 % of all pancreatic cancers) which have a much better outcome and chances of resection. Being mostly incidentalomas, a timely differentiation of this lesion from the much more common pseudocyst (which would mandate a medical management and a different surgical protocol) is the key for curability. Lastly, the neuroendocrine tumors of pancreas are equally rare (1 % of all pancreatic tumors), but importantly due to associated clinical syndromes and their capability to metastasize early in the course of disease, a timely detection may hence be the key for successful treatment of these lesions. Imaging plays a vital role in the initial detection and characterization as well as in determination of resectability of each of these pancreatic neoplasias. Further, the differentiation of pancreatic head tumors from other periampullary neoplasias is important; the fact that most recurrences are as a result of surgical intervention in an otherwise inoperable disease while most treatment failures are due to improper characterization of the lesion is notable.

Magnetic resonance imaging spectrum of solid pseudopapillary neoplasm of the pancreas

OBJECTIVE

To describe the magnetic resonance imaging spectrum of solid pseudopapillary tumors (SPTs), with an emphasis on solid SPTs.

METHODS

Thirty-two patients with proven SPTs with preoperative magnetic resonance were included. The SPTs were classified into 3 types: solid, cystic, and mixed; and 2 radiologists analyzed the images regarding the morphologic features and enhancement pattern.

RESULTS

Of 11 solid SPTs, 9 SPTs (81.8%) were less than 3 cm. Alternatively, of the 18 mixed SPTs and 3 cystic SPTs, 15 SPTs (71.4%) were larger than 3 cm. The predominant imaging features were homogeneous hypoenhancement with a gradually incremental enhancement pattern showing a sharp margin without hemorrhage, whereas those of the mixed SPTs were heterogeneous enhancement showing a sharp margin with internal hemorrhage.

CONCLUSION

Solid SPTs frequently present as small, well-defined tumors with a gradual enhancement and without hemorrhage or necrosis, and with features that differ from those of mixed or cystic SPTs.

Squamous-lined cyst of the pancreas: Radiological-pathological correlation

Pancreatic cystic lesions are increasingly being detected incidentally because of the increased use of cross-sectional imaging. Squamous-lined cysts of the pancreas (lymphoepithelial cyst, epidermoid cyst, and dermoid cyst) are rare cystic lesions lined with squamous epithelium. Distinguishing squamous-lined cysts from other cystic lesions of the pancreas is important to avoid unnecessary surgery, because squamous-lined cysts of the pancreas have no malignant potential. The purpose of this review is to describe findings on computed tomography and magnetic resonance imaging and the histopathological characteristics of squamous-lined cysts, and to summarize the key points of differential diagnosis for pancreatic cystic lesions.

Unusual features in an adult pancreatic hemangioma: CT and MRI demonstration

Hemangiomas in the pancreas are very rare and only a few cases in adulthood have been reported in the literature. We describe a case of pancreatic hemangiomas in an adult with unique imaging findings. A 23-year-old woman visited the hospital for an incidentally detected pancreatic mass. CT and MRI revealed a multilocular cyst with fluid-fluid levels and no obvious enhancement. The patient underwent surgery and the mass was confirmed as a pancreatic hemangioma. The radiological features and differential diagnosis of this rare lesion are discussed.

The incidental cystic pancreas mass: a practical approach

Technical advances in cross-sectional imaging have led to the discovery of incidental cystic pancreatic lesions in the oncology and non-oncology population that in the past remained undetected. These lesions have created a diagnostic and management dilemma for both clinicians and radiologists: should these lesions be ignored, watched, aspirated, or removed? In this review, recommendations concerning the assessment of the more common pancreatic cystic incidental lesions are presented.

Pancreatic cystic lesions: How endoscopic ultrasound morphology and endoscopic ultrasound fine needle aspiration help unlock the diagnostic puzzle

Cystic lesions of the pancreas are being diagnosed with increasing frequency, covering a vast spectrum from benign to malignant and invasive lesions. Numerous investigations can be done to discriminate between benign and non-evolutive lesions from those that require surgery. At the moment, there is no single test that will allow a correct diagnosis in all cases. Endoscopic ultrasound (EUS) morphology, cyst fluid analysis and cytohistology with EUS-guided fine needle aspiration can aid in this difficult diagnosis.