Value of 18-fluorodeoxyglucose positron emission tomography in the management of patients with cystic tumors of the pancreas

Misdiagnosis of pancreatic intraductal papillary mucinous neoplasms and the challenge of mimicking lesions: imaging diagnosis and differentiation strategies

The rising prevalence of pancreatic cystic lesions (PCLs), particularly intraductal papillary neoplasms (IPMNs), has been attributed to increased utilization of advanced imaging techniques. Incidental detection of PCLs is frequent in abdominal CT and MRI scans, with IPMNs representing a significant portion of these lesions. Surveillance of IPMNs is recommended due to their malignant potential; however, their overlapping imaging features with benign entities can lead to misdiagnosis, overtreatment, and overutilization of healthcare resources. This paper aims to highlight and differentiate lesions often mistaken for IPMNs, providing insight into their imaging characteristics, diagnostic challenges, and distinctive features while highlighting the incidence of wrong diagnosis for these lesions. These lesions include serous cystadenomas, cystic pancreatic neuroendocrine tumors, mucinous cystic neoplasms, lymphoepithelial cysts, duodenal diverticula, pancreatic schwannomas, chronic pancreatitis, retention cysts, intrapancreatic accessory spleens, pancreatic lipomas, choledochal cysts, and others. Utilizing various imaging modalities, including contrast-enhanced CT, MRI, and EUS, alongside histological and molecular analyses, can aid in accurate diagnosis and appropriate management. Understanding these mimicry scenarios is crucial to avoid unnecessary surveillance, interventions, and the burden they place on both patients and healthcare systems. Improved recognition of these lesions can lead to better patient outcomes and resource allocation.

Usefulness of 18F-fluorodeoxyglucose-positron emission tomography/computed tomography in primary cystadenocarcinoma of the mesentery: a case report

BACKGROUND

Mesenteric cysts have various histological forms, including mesenteric cystadenomas and borderline cystic neoplasms. Primary cystadenocarcinoma of the mesentery is extremely rare; therefore, the clinical and radiological features of this tumor have not been fully elucidated.

CASE PRESENTATION

A 50-year-old Japanese woman had a complaint of a left-sided abdominal distention. Enhanced computed tomography and magnetic resonance imaging revealed a unilocular cystic lesion measuring approximately 10 cm located in the left side of the abdomen. ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) revealed mottled mild FDG uptake in the cyst wall and intense FDG uptake in several mural nodules. The cystic mass with the descending colon was completely removed. Pathological examination of the specimens revealed various histologic patterns of adenocarcinoma, including mucin production in the mural nodules. We eventually diagnosed a primary cystadenocarcinoma arising from the mesentery of the descending colon.

CONCLUSIONS

Malignancy should be suspected in mesenteric or retroperitoneal cystic tumors with high FDG uptake, and complete resection should be performed with adequate margins.

The Role of Positron Emission Tomography in Clinical Management of Intraductal Papillary Mucinous Neoplasms of the Pancreas

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas represent a heterogeneous group of tumors, increasingly diagnosed in clinical practice. An early differential diagnosis between malignant and benign lesions is crucial to patient management and the choice of surgery or observation. The therapeutic approach is currently based on a patient’s clinical, biochemical, and morphological characteristics. The latest published International Consensus Guidelines (ICG) make no mention of the role of metabolic assessments of IPMNs. The aim of this study was to review the current literature, examining the role of 18-fluorodeoxyglucose (FDG) positron emission tomography (PET) in IPMN management. An extensive literature review was conducted according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and 10 articles were analyzed in detail, focusing on the value of PET as opposed to other standard imaging criteria. Data were retrieved on 419 patients. The 18-FDG-PET proved more sensitive, specific, and accurate than the ICG criteria in detecting malignant IPMNs (reaching 80%, 95%, and 87% vs. 67%, 58%, and 63%, respectively). Metabolic assessments may be used as an additional tool for the appropriate management of patients with doubtful imaging findings.

Pattern of use of positron emission tomography/computed tomography (PET/CT) scan in non-colorectal gastrointestinal cancers at KFSHRC, Riyadh, Saudi Arabia

Background

Positron emission tomography/computed tomography (PET/CT) scan is useful if clinically indicated. It is not for conventional routine use due to its high cost. Moreover, it can be confusing if ordered in non-indicated conditions. We evaluate if the pattern of PET/CT ordered in gastrointestinal cancers (non-colorectal origin) has followed evidence-based guidelines and whether it helped in the improvement of patient’s outcome. This study included non-colorectal gastrointestinal cancer patients from 2007 to 2008 who had one or more PET/CT scans done during their management. In each case, data collected revealed whether PET/CT affected the management or the stage or not. Patients were identified through the hospital tumor registry software CNExT (C/NET Solutions, Berkeley, CA). Tabulation and statistical data analysis were done using JMP-SAS statistical software application (version 9.4: SAS Institute, Cary, NC, USA). The scan report quality and use indications were outlined.

Results

Seventy-seven patients were identified, with 107 PET/CT scans done. Their median age is 59 (21–86) years. Males were 45 (58.5%). Tumor origin was 46.8% esophageal and gastroesophageal junction cancer, 15.6% gastric cancer, 11.7% pancreatic cancer, 11.7% hepatobiliary tumors, 10.4% neuroendocrine tumors, 2.6 % gastrointestinal stromal tumors, and 1.3% small bowel cancer. Indications of the PET/CT were as follows: staging in 59.8%, follow-up after finishing treatment in 14.9%, restaging at relapse in 8.4%, assessing response after/during treatment in 3.7%, follow-up of previous PET/CT in 12.1%, and others in 0.9%. PET/CT changed the stage in 19.6% and affected the management plan in 11.2% only. Fifty-two scans needed pathological pursuit as decided by investigators; of them, PET/CT for the lesions that could have changed the stage reported indeterminate/equivocal results in 32 (29.9%) of all scans. The pathological pursuit for the equivocal lesions on PET/CT scans was done in only 12 of 52 (23.1%) scans.

Conclusions

Local guidelines for ordering PET/CT scan are suggested because overuse was documented, and an evidence-based approach should be respected before its use.

A Surgically Resected Pancreatic Schwannoma with Obstructive Jaundice with Special Reference to Differential Diagnosis from Other Cystic Lesions in the Pancreas

Pancreatic schwannomas are uncommon. About 60% of pancreatic schwannomas develop cystic lesions, and the differential diagnosis from other cystic pancreatic tumors is difficult. A 43-year-old man presented for evaluation of liver dysfunction detected during a medical checkup. Blood testing detected obstructive jaundice. A computed tomography scan revealed a well-defined polycystic tumor of about 5 cm at the pancreatic head. We performed surgical resection to treat the patient's symptoms and facilitate long-term management. Histopathological examination revealed spindle-shaped cells. Immunohistochemical studies showed S100 protein expression and the absence of CD34 and c-kit protein expression. Finally, we diagnosed a schwannoma. Pancreatic schwannoma is usually asymptomatic. The present case presented with obstructive jaundice, which is reportedly a rare symptom. Pancreatic schwannomas should be considered as a differential diagnosis of pancreatic cystic tumors. Dilatation of the pancreatic duct and the 18-fluorodeoxyglucose positron emission tomography findings are important for the differential diagnosis.

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 the Pancreas: A Single Center Experience

Aim of this study was to review the institutional experience of solid-pseudopapillary tumors of the pancreas with particular attention to the problems of preoperative diagnosis and treatment. From 1997 to 2013, SPT was diagnosed in 18 patients among 451 pancreatic cystic neoplasms (3.7%). All patients underwent preoperative abdominal ultrasound, computed assisted tomography, and tumor markers (CEA and CA 19-9) determinations. In some instances, magnetic resonance, positron emission tomography, and endoscopic ultrasound with aspiration cytology were performed. There were two males and 16 females. Serum CA 19-9 was slightly elevated in one case. Preoperative diagnosis was neuroendocrine tumor (n = 2), mucinous tumor (n = 2), and SPT (n = 14). Two patients underwent previous operation before referral to our department: one explorative laparotomy and one enucleation of SPT resulting in surgical margins involvement. All patients underwent pancreatic resection associated with portal vein resection (n = 1) or liver metastases (n = 1). One patient died of metastatic disease, 77 months after operation, and 17 are alive and free with a median survival time of 81.5 months (range 36–228 months). Most of SPT can be diagnosed by CT or MRI, and the role of other diagnostic tools is very limited. We lack sufficient information regarding clinicopathologic features predicting prognosis. Caution is needed when performing limited resection, and long and careful follow-up is required for all patients after surgery.

Imaging of pancreatic neoplasms

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

Accuracy of 18F-FDG PET/CT, Multidetector CT, and MR Imaging in the Diagnosis of Pancreatic Cysts: A Prospective Single-Center Study

Accurate diagnosis of the nature of pancreatic cysts is challenging but more important than ever, in part because of the increasing number of incidental cystic findings in the pancreas. Preliminary data suggest that (18)F-FDG PET/CT may have a significant influence on clinical decision making, although its role is still evolving. Our aim was to prospectively compare the accuracy of combined (18)F-FDG PET and contrast-enhanced CT ((18)F-FDG PET/CT), multidetector CT (MDCT), and MR imaging in differentiating malignant from benign pancreatic cysts.

METHODS

Thirty-one consecutive patients with pancreatic cysts were enrolled in the study. They underwent a protocol including (18)F-FDG PET/CT, MDCT, and MR imaging combined with MR cholangiopancreatography, all of which were evaluated in a masked manner. The findings were confirmed macroscopically at surgery or histopathologic analysis (n = 22) or at follow-up (n = 9).

RESULTS

Of the 31 patients, 6 had malignant and 25 had benign lesions. The diagnostic accuracy was 94% for (18)F-FDG PET/CT, compared with 77% and 87% for MDCT (P < 0.05) and MR imaging, respectively. (18)F-FDG PET/CT had a negative predictive value of 100% and a positive predictive value of 75% for pancreatic cysts. The maximum standardized uptake value was significantly higher in malignant (7.4 ± 2.6) than in benign lesions (2.4 ± 0.8) (P < 0.05). When the maximum standardized uptake value was set at 3.6, the sensitivity and specificity were 100% and 88%, respectively. Furthermore, when compared with MDCT and MR imaging, respectively, (18)F-FDG PET/CT altered the clinical management of 5 and 3 patients, respectively.

CONCLUSION

(18)F-FDG PET/CT is an accurate imaging modality for differentiating between benign and malignant pancreatic cysts. We recommend the use of (18)F-FDG PET/CT in the evaluation of diagnostically challenging pancreatic cysts.

Role of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography in gastrointestinal cancers

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has become a routine imaging modality for many malignancies and its use is currently increasing. In the present review article, we will summarize the evidence for FDG-PET/CT use in digestive cancers (excluding neuroendocrine tumours), and review the existing recommendations. While PET/CT is nowadays considered to be an important tool in the initial workup of oesophageal and anal cancers, new data are emerging regarding its use in assessing therapeutic efficacy, radiotherapy treatment planning, and detection of recurrence in case of isolated tumour marker elevation. Moreover, PET/CT may help decision making by detecting distant metastatic sites especially in potentially resectable metastatic colorectal cancer and, to a lesser extent, in localized gastric and pancreatic cancers. Finally, incidental focal colonic FDG uptakes require exploration by colonoscopy, as they are often associated with premalignant or malignant lesions.

Comparing the performance of visual estimation and standard uptake value of F-18 fluorodeoxyglucose positron emission tomography/computed tomography for detecting malignancy in pancreatic tumors other than invasive ductal carcinoma

INTRODUCTION

The utility of FDG PET/CT for the detection and evaluation of invasive ductal carcinoma has been widely reported, but a few studies have assessed the utility of FDG PET/CT to detect malignancy in a variety of pancreatic lesions other than invasive ductal carcinoma.

PURPOSE

To compare the diagnostic performance of visual estimation with the semi-quantitative scores of FDG PET/CT for detecting malignancy in a variety of pancreatic lesions other than invasive ductal carcinoma.

MATERIAL AND METHODS

Images of pathologically proven pancreatic lesions from 32 patients were retrospectively evaluated: 14 benign lesions, 7 borderline (low malignant) lesions, and 11 malignant lesions. The average scores from visual estimation by the two observers were compared to two semi-quantitative analyses of FDG uptake in the lesions, namely the maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean).

RESULTS

Visual analysis value, SUVmax and SUVmean were 0.33 ± 0.21, 1.8 ± 0.7 and 1.5 ± 0.7 for the benign lesions, 0.70 ± 0.28, 5.0 ± 2.6 and 3.1±1.7 for the borderline lesions, and 0.73 ± 0.18, 4.7 ± 2.5 and 3.2 ± 1.6 for the malignant lesions, respectively. Receiver operating characteristic analysis revealed the areas under the curves for detecting non-benign (malignant or borderline) lesions through visual analysis, SUVmax, and SUVmean were 0.914, 0.954, and 0.875, respectively.

CONCLUSION

For a variety of pancreatic lesions other than invasive ductal carcinoma, visual analysis and semi-quantitative analyses all showed strong diagnostic performance. However, semi-quantitative analysis with SUVmax proved to be the most effective method for detecting non-benign pancreatic lesions.

F-18 fluorodeoxyglucose positron emission tomography for differential diagnosis of pancreatic tumors

Positron emission tomography with 2-deoxy-2-[¹⁸F]fluoro-D-glucose (FDG-PET) has been proven useful for differentiating pancreatic ductal cancer from mass-forming chronic pancreatitis. However, there are particular pancreatic tumors having various grades of malignancy such as intraductal papillary mucinous neoplasm (IPMN) or pancreatic neuroendocrine tumor. We examined whether the cut-off value of maximum standardized uptake value (SUV_max) determined by pancreatic ductal cancers is also applicable for other pancreatic tumors.

One hundred thirty six patients with pancreatic tumors underwent FDG-PET imaging. We first analyzed the cut-off value to differentiate pancreatic ductal cancers from mass-forming chronic pancreatitis. Secondly, we determined the cut-off value between malignant IPMN and benign IPMN. Thirdly, we computed a cut-off value between malignant pancreatic tumors and benign tumors irrespective of tumor type.

The optimal cut-off value to differentiate ductal cancers from mass-forming chronic pancreatitis was 2.5. The optimal cut-off value for differentiating malignant IPMN from benign IPMN was also 2.5, similar to that of reported studies. In all types of pancreatic tumors, the cut-off value was also 2.5. The accuracy for detecting malignancy was 93.4% for all tumors.

In the FDG-PET study for pancreatic tumors, an SUV_max of 2.5 would be justified as a cut-off value to differentiate malignant lesions.

Importance of Defect Detectability in Positron Emission Tomography Imaging of Abdominal Lesions

OBJECTIVES

This study was designed to assess defect detectability in positron emission tomography (PET) imaging of abdominal lesions.

METHODS

A National Electrical Manufactures Association International Electrotechnical Commission phantom was used. The simulated abdominal lesion was scanned for 10 min using dynamic list-mode acquisition method. Images, acquired with scan duration of 1-10 min, were reconstructed using VUE point HD and a 4.7 mm full-width at half-maximum (FWHM) Gaussian filter. Iteration-subset combinations of 2-16 and 2-32 were used. Visual and physical analyses were performed using the acquired images. To sequentially evaluate defect detectability in clinical settings, we examined two middle-aged male subjects. One had a liver cyst (approximately 10 mm in diameter) and the other suffered from pancreatic cancer with an inner defect region (approximately 9 mm in diameter).

RESULTS

In the phantom study, at least 6 and 3 min acquisition durations were required to visualize 10 and 13 mm defect spheres, respectively. On the other hand, spheres with diameters ≥17 mm could be detected even if the acquisition duration was only 1 min. The visual scores were significantly correlated with background (BG) variability. In clinical settings, the liver cyst could be slightly visualized with an acquisition duration of 6 min, although image quality was suboptimal. For pancreatic cancer, the acquisition duration of 3 min was insufficient to clearly describe the defect region.

CONCLUSION

The improvement of BG variability is the most important factor for enhancing lesion detection. Our clinical scan duration (3 min/bed) may not be suitable for the detection of small lesions or accurate tumor delineation since an acquisition duration of at least 6 min is required to visualize 10 mm lesions, regardless of reconstruction parameters. Improvements in defect detectability are important for radiation treatment planning and accurate PET-based diagnosis.

Predicting dysplasia and invasive carcinoma in intraductal papillary mucinous neoplasms of the pancreas: development of a preoperative nomogram

BACKGROUND

Clinical decision making for patients with intraductal papillary mucinous neoplasms (IPMN) of the pancreas is challenging. Even with strict criteria for resection, most resected lesions lack high-grade dysplasia (HGD) or invasive carcinoma.

METHODS

We evaluated patients who underwent resection of histologically confirmed IPMN and had preoperative imaging available for review. A hepatobiliary radiologist blinded to histopathologic subtype reviewed preoperative imaging and recorded cyst characteristics. Patients with mixed-type IPMN were grouped with main-duct lesions for this analysis. Based on an ordinal logistic regression model, we devised two independent nomograms to predict the findings of adenoma, high-grade dysplasia (HGD-CIS), and invasive carcinoma, separately in both main and branch-duct IPMN. Bootstrap validation was used to evaluate the performance of these models, and a concordance index was derived from this internal validation.

RESULTS

There were 219 patients who met criteria for this study. Branch-duct IPMN (bdIPMN) comprised 56 % of the resected lesions. The proportion of HGD-CIS was 15 % for bdIPMN and 33 % for main-duct lesions (mdIPMN); P = 0.003. Invasive carcinoma was identified in 15 % of bdIPMN and 41 % of main-duct lesions (P < 0.001). On multivariate regression, patient gender, history of prior malignancy, presence of solid component, and weight loss were found to be significantly associated with the ordinal outcome for patients with mdIPMN and built into the nomogram (concordance index 0.74). For patients with bdIPMN weight loss, solid component, and lesion diameter were associated with the outcome; (concordance index 0.74).

CONCLUSION

Based on the analysis of patients selected for resection, two nomograms were created that predict a patient's individual likelihood of harboring HGD or invasive malignancy in radiologically diagnosed IPMN. External validation is ongoing.

Pancreatic cystic neoplasms: a review of preoperative diagnosis and management

Pancreatic cystic neoplasms (PCNs) are a diverse group of neoplasms in the pancreas, and are more increasingly encountered with widespread abdominal screening and improved imaging techniques. The most common types of PCNs are serous cystic neoplasms (SCNs), mucinous cystic neoplasms (MCNs), and intraductal papillary mucinous neoplasms (IPMNs). Clinicians frequently feel bewildered in the differential diagnosis and subsequent management among the various types of lesions in the pancreas, which may lead to overtreatment or delayed treatment. The current review provides recent developments in the understanding of the three most common types of PCNs, the latest modalities used in preoperative diagnosis and differential diagnosis, as well as the most up to date management. Suggestions for diagnosis and differential diagnosis of SCNs, MCNs, and IPMNs are also provided for young surgeons. Better understanding of these neoplasms is essential for clinicians to make accurate diagnosis and to provide the best management for patients.

Imaging of indeterminate pancreatic cystic lesions: a systematic review

BACKGROUND

Pancreatic cystic lesions are an increasing problem and investigation of these cysts can be fraught with difficulty. There is currently no gold standard for diagnosis or surveillance. This review was undertaken to determine the present reliability of the characterisation, assessment of malignant potential and diagnosis of pancreatic cystic lesions using available imaging modalities.

METHODS

A Medline search using the terms 'pancreatic', 'pancreas', 'cyst', 'cystic', 'lesions', 'imaging', 'PET'. 'CT', 'MRI' and 'EUS' was performed. Publications were screened to include studies examining the performance of CT, MRI, MRCP, EUS and 18-FDG PET in the determination of benign or malignant cysts, cyst morphology and specific diagnoses.

RESULTS

Nineteen studies were identified that met the inclusion criteria. 18-FDG PET had a sensitivity and specificity of 57.0-94.0% and 65.0-97.0% and an accuracy of 94% in determining benign versus malignant cysts. CT had a sensitivity and specificity of 36.3-71.4% and 63.9-100% in determining benign disease but had an accuracy of making a specific diagnosis of 39.0-44.7%. MRI had a sensitivity and specificity of 91.4-100.0% and 89.7% in assessing main pancreatic duct communication.

CONCLUSION

CT is a good quality initial investigation to be used in conjunction with clinical data. MRCP can add useful information regarding MPD communication but should be used judiciously. PET may have a role in equivocal cases to determine malignancy. Further examination of CT-PET in this patient group is warranted.

The usefulness of (18)F-FDG PET/MRI fusion image in diagnosing pancreatic tumor: comparison with (18)F-FDG PET/CT

PURPOSE

This study aimed at demonstrating the feasibility of retrospectively fused (18)F FDG-PET and MRI (PET/MRI fusion image) in diagnosing pancreatic tumor, in particular differentiating malignant tumor from benign lesions. In addition, we evaluated additional findings characterizing pancreatic lesions by FDG-PET/MRI fusion image.

METHODS

We analyzed retrospectively 119 patients: 96 cancers and 23 benign lesions. FDG-PET/MRI fusion images (PET/T1 WI or PET/T2WI) were made by dedicated software using 1.5 Tesla (T) MRI image and FDG-PET images. These images were interpreted by two well-trained radiologists without knowledge of clinical information and compared with FDG-PET/CT images. We compared the differential diagnostic capability between PET/CT and FDG-PET/MRI fusion image. In addition, we evaluated additional findings such as tumor structure and tumor invasion.

RESULTS

FDG-PET/MRI fusion image significantly improved accuracy compared with that of PET/CT (96.6 vs. 86.6 %). As additional finding, dilatation of main pancreatic duct was noted in 65.9 % of solid types and in 22.6 % of cystic types, on PET/MRI-T2 fusion image. Similarly, encasement of adjacent vessels was noted in 43.1 % of solid types and in 6.5 % of cystic types. Particularly in cystic types, intra-tumor structures such as mural nodule (35.4 %) or intra-cystic septum (74.2 %) were detected additionally. Besides, PET/MRI-T2 fusion image could detect extra benign cystic lesions (9.1 % in solid type and 9.7 % in cystic type) that were not noted by PET/CT.

CONCLUSIONS

In diagnosing pancreatic lesions, FDG-PET/MRI fusion image was useful in differentiating pancreatic cancer from benign lesions. Furthermore, it was helpful in evaluating relationship between lesions and surrounding tissues as well as in detecting extra benign cysts.

FDG PET/CT detects clinically occult pancreatic cancer in a case of Von Hippel-Lindau syndrome

Von Hippel-Lindau (VHL) disease is a rare, inherited, multisystem disorder that is characterized by development of a variety of benign and malignant tumors. We report an incidental detection of clinically occult pancreatic malignancy on FDG PET/CT in a patient of VHL who underwent restaging for a previously treated endolymphatic sac tumor.

F18-FDG-PET/CT for evaluation of intraductal papillary mucinous neoplasms (IPMN): a review of the literature

Intraductal papillary mucinous neoplasms (IPMN) are intraductal mucin-producing neoplasms with tall columnar, mucin-containing epithelium, with or without papillary projections, involving the main pancreatic duct and/or major side branches. They account for approximately 25 % of all cystic neoplasms and can be subdivided into benign lesions, borderline lesions, and carcinoma. In this clinical scenario accurate preoperative diagnosis can eliminate unnecessary surgery, which is risky and potentially harmful, yet enable effective selection of patients who are candidates for surgery. In this review we try to provide a complete evaluation of the use of F18-FDG-PET/CT for diagnosis of this neoplasm on the basis of published papers. F18-FDG-PET/CT seems to be an useful technique for preoperative work-up of patients with suspected IPMN and is an improvement over conventional imaging in distinguishing benign from malignant lesions, especially for selecting patients for surgical treatment or for long-term follow-up.

18F-fluorodeoxyglucose positron emission tomography in management of pancreatic cystic tumors

OBJECTIVES

To evaluate the effectiveness of PET in differentiating malignant from benign pancreatic cystic tumors.

METHODS

Between 2009 and 2010, all patients with pancreatic cystic tumors who had PET, triple phase contrast computed tomography (CT) and endoscopic ultrasound (EUS) were reviewed. Clinicopathological characteristics and final histology were correlated with preoperative PET, CT and EUS to assess the value of each modality in detecting malignant from benign lesions for clinical decision-making.

RESULTS

Twenty of a total of 116 patients with pancreatic cystic tumors had 18F-FDG PET because of diagnostic difficulties after evaluation with conventional modalities. Sensitivity and specificity of PET in differentiating malignant from benign pancreatic cystic tumors were 100% and 93.75%, with an accuracy of 95%. PET had the best sensitivity, specificity and accuracy for detecting malignant cystic tumors compared with CT and EUS. In 5 cases, the PET results altered the treatment options completely to follow-up instead of surgery (n=2), limited resection instead of Whipple's resection (n=1), and surgery instead of follow-up (n=2).

CONCLUSIONS

PET is an accurate, non-invasive method to distinguish malignant from benign pancreatic cystic tumors and can be used as an adjunct to facilitate clinical decision making.

Positron emission tomography in hepatobiliary and pancreatic malignancies: a review

BACKGROUND

The prognosis for hepatobiliary and pancreatic malignancies is dismal. Surgery remains the primary curative option, but unresectable disease is often discovered during operative exploration. Positron emission tomography (PET) provides unique biological information different from current imaging modalities. The role of PET in detecting hepatobiliary and pancreatic malignancies has not yet been established. The purpose of this article was to review the literature on the use of PET in hepatobiliary and pancreatic malignancies.

DATA SOURCES

We performed an extensive search on PubMed using PET and hepatocellular, pancreatic, gallbladder, and cholangiocarcinoma as keywords, excluding articles not written in English or on nonhuman subjects, case reports, and series with <5 patients.

CONCLUSIONS

Although PET has shown usefulness in the diagnosis of certain cancers, current literature cautions against the use of PET for determining malignant potential of primary liver and pancreatic lesions. Literature on PET more strongly supports clinical roles for restaging of hepatobiliary and pancreatic malignancies, and for identifying metastatic disease.

Cystic tumors of the pancreas: imaging and management

Cystic tumors of the pancreas are a subset of rare pancreatic tumors that vary from benign to malignant. Many have specific imaging findings that allow them to be differentiated from each other. This article (1) reviews the imaging features of the common cystic pancreatic lesions, including serous microcystic adenoma, mucinous cystic tumor, intraductal papillary mucinous tumor, and solid pseudopapillary tumor, and including the less common lesions such as cystic endocrine tumors, cystic metastases, cystic teratomas, and lymphangiomas; and (2) provides comprehensive algorithms on how to manage the individual lesions, with recommendations on when to reimage patients.

Laparoscopic resection of epidermoid cyst arising from an intrapancreatic accessory spleen: a case report with a review of the literature

We describe a rare case of epidermoid cyst arising in an intrapancreatic accessory spleen that presented as a cystic mass in the tail of the pancreas, and for which laparoscopic distal pancreatectomy was performed successfully. A 36-year-old woman with a cystic mass in the tail of the pancreas, which had been discovered incidentally at a medical checkup, was referred to our department for further examination. Endoscopic retrograde cholangiopancreatography, endoscopic ultrasonography and positron emission tomography demonstrated a multilocular cyst in the tail of the pancreas without any evidence of malignancy, although differential diagnosis was extremely difficult because of the neoplasm-like appearance of the lesion. Therefore, we performed laparoscopic distal pancreatectomy under a preoperative diagnosis of mucinous cystic neoplasm. Postoperative pathologic examination demonstrated an epidermoid cyst arising from a heterotopic spleen within the pancreas. This is the first report of successful laparoscopic distal pancreatectomy for an epidermoid cyst arising in an intrapancreatic accessory spleen. One virtually has no chance to diagnose an epidermoid cyst in an accessory spleen on the basis of preoperative diagnostic workup, and consequently the type of surgical resection (open vs. laparoscopic) would be conditioned by factors other than the clinical entity suspected at the preoperative period.

Impact of F18-fluorodeoxyglycose positron emission tomography/computed tomography on the management of resectable pancreatic tumours

BACKGROUND

Positron emission tomography/computed tomography (PET/CT) using F18-fluorodeoxyglucose has been shown to be valuable in the management of malignant disease. The aim of this study is to investigate the impact of this technique on the management of patients with resectable pancreatic tumours.

METHODS

Thirty-six patients with 37 potentially resectable pancreatic tumours on diagnostic CT imaging underwent PET/CT scans. Operative findings, histological reports and/or clinical follow-up served as standard of reference. The impact of PET/CT on patient management was estimated by calculating the percentage of patients whose treatment plan was altered due to PET/CT.

RESULTS

Pancreatic adenocarcinoma was diagnosed in 30 patients, neuroendocrine tumours in 3, mass-forming pancreatitis in 3 and serous cystadenoma in 1. The median standard uptake (max) value was 5.0 (range 2.2-12.0). Sensitivity and specificity of detecting extrapancreatic metastatic disease were 73% and 100%, respectively. Three occult liver metastases were detected at laparotomy following negative PET/CT. PET/CT findings influenced the management of 8 (22%) patients - 3 with liver metastases, 3 with bone metastases, 1 with lymph node metastases and 1 by identifying the benign appearance of the pancreatic tumour.

CONCLUSION

PET/CT achieves a significant diagnostic impact in detecting extrapancreatic metastatic disease. F18-fluorodeoxyglucose PET/CT appears to be useful in assessing suspicious pancreatic masses.

Comparison of International Consensus Guidelines versus 18-FDG PET in detecting malignancy of intraductal papillary mucinous neoplasms of the pancreas

OBJECTIVE

To assess the reliability of the International Consensus Guidelines (ICG) and 18-fluorodeoxyglucose positron emission tomography (PET) in distinguishing benign from malignant intraductal papillary mucinous neoplasms (IPMNs) of the pancreas.

BACKGROUND

Since 2006 the ICG have been used to choose immediate surgery or surveillance for IPMN patients, but their low specificity increases the number of benign IPMNs that undergo resective surgery. PET has proved highly sensitive and specific in detecting malignancy in cystic neoplasms of the pancreas, including IPMNs.

METHODS

Patients suspected with IPMNs of the pancreas seen at our Department from January 1989 to July 2010 were identified and classified as cases of main duct, mixed type and branch type IPMN. The indication for resection or surveillance was verified a posteriori for all patients according to the ICG. PET was considered positive for a Standardized Uptake Value ≥2.5. Surveillance included clinical examination, laboratory tests, CA 19-9 serum levels, and computed tomography and/or magnetic resonance and magnetic resonance cholangiopancreatography every 6 months for 2 years and yearly thereafter. Endoscopic ultrasound was rarely performed. PET was repeated in clinically or radiologically suspect cases, or if tumor markers increased.

RESULTS

Sixty-one main duct or mixed type and 101-branch type IPMNs were included in the study. A histological diagnosis was available for 81 of 162 patients, missing for 1 locally advanced IPMN, whereas 62 patients are under surveillance and it proved impossible to contact 18. Conservative surgery was performed in 16 of 68 patients with benign IPMNs. The sensitivity, specificity, positive and negative predictive value, and accuracy of the ICG in detecting malignancy were 93.2, 22.2, 59.4, 72.7, and 61.2, whereas for PET they were 83.3, 100, 100, 84.6, and 91.3.

CONCLUSIONS

PET is more accurate than the ICG in distinguishing benign from malignant (invasive and noninvasive) IPMNs. Prophylactic IPMN resection in young patients fit for surgery should be guided by the ICG, whereas PET should be performed in older patients, cases at increased surgical risk, or when the feasibility of parenchyma-sparing surgery demands a reliable preoperative exclusion of malignancy.

Imaging of the pancreas: Recent advances

A wide spectrum of anomalies of pancreas and the pancreatic duct system are commonly encountered at radiological evaluation. Diagnosing pancreatic lesions generally requires a multimodality approach. This review highlights the new advances in pancreatic imaging and their applications in the diagnosis and management of pancreatic pathologies. The mainstay techniques include computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasound (EUS), radionuclide imaging (RNI) and optical coherence tomography (OCT).

New trends in diffusion-weighted magnetic resonance imaging as a tool in differentiation of serous cystadenoma and mucinous cystic tumor: a prospective study

BACKGROUND/AIMS

Pancreatic cystic lesions are increasingly being recognized. Magnetic resonance imaging (MRI) is the method that brings the greatest amount of information about the morphologic features of pancreatic cystic lesions. To establish if diffusion-weighted MRI (DW-MRI) can be used as a tool to differentiate mucinous from nonmucinous lesions.

METHODS

Fifty-six patients with pancreatic cystic lesions (benign, n = 46; malignant, n = 10) were prospectively evaluated with DW-MRI in order to differentiate mucinous from nonmucinous lesions. Final diagnosis was obtained by follow-up (n = 31), surgery (n = 16) or endoscopic ultrasound-guided fine needle aspiration (n = 9). Serous cystadenoma was identified in 32 (57%) patients.

RESULTS

The threshold value established for the differentiation of mucinous from nonmucinous lesions was 2,230.06 s/mm(2) for ADC of 700. DWI-MRI behavior between mucinous and nonmucinous groups revealed sensitivity, specificity, positive predictive value, negative predictive value and accuracy to be 80, 98, 92, 93 and 93%, respectively (p < 0.01, power of sample = 1.0). In the comparison of the diffusion behavior between mucinous (n = 13) and serous (n = 32) lesions, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 100, 97, 92, 100 and 98%, respectively (p < 0.01, power of sample = 1.0). The results of endoscopic ultrasound-guided fine needle aspiration were similar to those of DW-MRI.

CONCLUSIONS

DW-MRI can be included as part of the array of tools to differentiate mucinous from nonmucinous lesions and can help in the management of pancreatic cystic lesions. and IAP.

The utility of F-18 FDG PET/CT in the evaluation of pancreatic intraductal papillary mucinous neoplasm

PURPOSE

To assess the utility of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in evaluating pancreatic intraductal papillary mucinous neoplasm (IPMN).

MATERIALS AND METHODS

We included 31 patients with pancreatic IPMN who underwent F-18 FDG PET/CT and multidetector CT (MDCT). Each pancreatic lesion was classified as benign or malignant. On PET, the maximal standardized uptake value was measured in each pancreatic lesion.

RESULTS

PET/CT was superior to MDCT in diagnosing malignant IPMN. All 22 concordant results gave accurate diagnoses. Of 9 discordant results, MDCT misdiagnosed 7 IPMNs, whereas PET/CT misinterpreted 2. Malignant IPMNs showed significantly higher maximal standardized uptake values (mean ± standard deviation, 6.7 ± 3.6) than benign IPMNs (mean ± standard deviation, 2.1 ± 1.0) (P < 0.001).

CONCLUSIONS

F-18 FDG PET/CT outperformed MDCT in detecting malignant IPMN.

Management of mucinous cystic neoplasms of the pancreas

The purpose of this study was to investigate the actual management of mucinous cystic neoplasm (MCN) of the pancreas. A systematic review was performed in December 2009 by consulting PubMed MEDLINE for publications and matching the key words “pancreatic mucinous cystic neoplasm”, “pancreatic mucinous cystic tumour”, “pancreatic mucinous cystic mass”, “pancreatic cyst”, and “pancreatic cystic neoplasm” to identify English language articles describing the diagnosis and treatment of the mucinous cystic neoplasm of the pancreas. In total, 16 322 references ranging from January 1969 to December 2009 were analysed and 77 articles were identified. No articles published before 1996 were selected because MCNs were not previously considered to be a completely autonomous disease. Definition, epidemiology, anatomopathological findings, clinical presentation, preoperative evaluation, treatment and prognosis were reviewed. MCNs are pancreatic mucin-producing cysts with a distinctive ovarian-type stroma localized in the body-tail of the gland and occurring in middle-aged females. The majority of MCNs are slow growing and asymptomatic. The prevalence of invasive carcinoma varies between 6% and 55%. Preoperative diagnosis depends on a combination of clinical features, tumor markers, computed tomography (CT), magnetic resonance imaging, endoscopic ultrasound with cyst fluid analysis, and positron emission tomography-CT. Surgery is indicated for all MCNs.

Role and limitations of 18F-FDG positron emission tomography (PET) in the management of patients with pancreatic lesions

The 18-fluorine-18-fluoro-2-deoxyglucose Positron Emission Tomography coupled with computed tomography is a non invasive exploration. Several studies have shown that PET-CT has superior efficacy over conventional imaging techniques in distinguishing a benign pancreatic tumor from a malignant one. It contributes to the diagnosis of cancer in patients with a doubtful mass, much more in case of chronic pancreatitis. PET-CT is also an important help for the diagnosis of cystic tumors of the pancreas; the results can affect the management strategy. It is interesting for the endocrine tumors, particularly since the emergence of new markers. The aim of this paper is to summarize the role and limitations of 18-F-FDG PET-CT in the management of patients with pancreatic lesions (adenocarcinoma, cystic tumors, endocrine tumors, etc…) concerning the malignancy diagnosis, the detection of metastases, the monitoring after non surgical treatments and to evaluate interpretation difficulties, particularly in case of diabetes or chronic pancreatitis.

Using 18F-fluorodeoxyglucose positron emission tomography to monitor clinical outcomes in patients treated with neoadjuvant chemo-radiotherapy for locally advanced pancreatic cancer

BACKGROUND

Pancreatic cancer ranks as the fourth leading cause of cancer death in the United States with 5-year survival ranging from 1% to 5%. Positron emission tomography (PET) is a metabolic imaging system that is widely used for the initial staging of cancer and detecting residual disease after treatment. There are limited data, however, on the use of this molecular imaging technique to assess early tumor response after treatment in pancreatic cancer.

METHODS

The objective of the study was to explore the relationship of early treatment response using the F-fluorodeoxyglucose (FDG) PET with surgical outcome and overall survival in patients with locally advanced pancreatic cancer. FDG-PET measurements of maximum standardized uptake value and kinetic parameters were compared with the clinical outcome.

RESULTS

Twenty patients were enrolled in the study evaluating neoadjuvant induction chemotherapy followed by concurrent chemoradiotherapy (chemo-RT) for locally advanced pancreatic cancer. All 20 patients had prestudy PET scans and a total of fifty PET scans were performed. Among patients who were PET responders (> or =50% decrease in standardized uptake value after cycle 1), 100% (2/2) had complete surgical resection. Only 6% (1/16) had surgical resection in the PET nonresponders (<50% decrease). Two patients did not have the second PET scan because of clinical progression or treatment toxicity. Mean survival was 23.2 months for PET responders and 11.3 months for nonresponders (P = 0.234). Similar differences in survival were also noted when response was measured using Patlak analysis.

CONCLUSIONS

FDG-PET can aid in monitoring the clinical outcome of patients with locally advanced pancreatic cancer treated with neoadjuvant chemo-RT. FDG-PET may be used to aid patients who could have complete surgical resection as well as prognosticate patients' survival.

Tumors of the Pancreatic Body and Tail

Tumors of the pancreatic body and tail are uncommon. They have a propensity to present late and often attain a large size with local invasion before they produce any clinical symptoms. The current review aims at comprehensively analysing these tumors with respect to their pathology, presentation, the investigation of these tumors, and finally the latest trends in their surgical and medical management.

Solitary true cyst of pancreas: report of a case and review of literature

CONTEXT

Solitary true cysts of the pancreas in adults are extremely rare, and only few cases have been reported in the literature. The etiology and natural history of these lesions remain unknown, and treatment is not standardized. We describe an additional resected case.

CASE REPORTS

A 55-year-old female who presented to us with a history of heaviness and pain in right upper abdomen for 1 year. CT scan of abdomen showed a large unilocular cyst in the region of the head of the pancreas. The patient underwent pancreatico-duodenectomy with binding pancreaticojejunostomy. The histology of cyst revealed true unilocular pancreatic cyst lined by cuboidal epithelium. She is well after 3 years of follow-up.

CONCLUSIONS

A preoperative work-up alone does not always allow an accurate diagnosis, but it is useful in determining lesion characteristics and guiding therapeutic decision-making. When surgery is indicated, a limited resection is warranted in most cases.

Preoperative assessment of para-aortic lymph node metastasis in patients with pancreatic cancer

BACKGROUND

Para-aortic lymph node (PALN) metastasis is an important prognostic factor in patients with pancreatic cancer, but accurate preoperative diagnosis is difficult. The objective of this study was to assess the accuracy of diagnosis of PALN by computed tomography (CT), magnetic resonance imaging (MRI), and (18)F-fluorodeoxyglucose positron-emission tomography (FDG-PET).

METHODS

From August 2005 to July 2008, 119 patients with invasive ductal adenocarcinoma of the pancreas were included in this study. PALNs with a longer diameter >10 mm on CT or MRI were suspected of being involved by metastasis, whereas FDG uptake exceeding that of the adjacent normal tissue was considered to be positive for metastasis on FDG-PET studies. The imaging findings were compared with the pathological diagnosis of PALN metastasis.

RESULTS

PALN dissection was performed in 71 patients (60.0%). Although histopathological examination revealed metastasis in 6 patients (8.5%), none of these patients was positive in any of the preoperative imaging studies. The longer diameter, the shorter diameter, the ratio of the two diameters, and the calculated lymph node volume showed no significant differences between patients with and without PALN metastasis.

CONCLUSIONS

Preoperative detection of PALN metastasis in patients with pancreatic cancer is very difficult. Intraoperative histopathological examination of frozen sections is necessary if radical resection is contemplated.

Small multicentric pancreatic carcinoma usefully diagnosed by positron emission tomography

Pancreatic carcinoma has a poor prognosis, and early detection is essential for potentially curative resection. Despite a wide array of diagnostic tools, pre-operative detection of small pancreatic carcinomas is difficult. We report a case of pancreatic carcinoma that was bicentric and small. The head mass was diagnosed by computed tomography (CT), while the tail mass, which was suspected but indeterminate on CT, was diagnosed by positron emission tomography (PET). Thus, total pancreatectomy was performed. The PET results prevented our patient from undergoing tail mass biopsy, multiple surgeries and non-curative operation.

Defining criteria for selective operative management of pancreatic cystic lesions: does size really matter?

INTRODUCTION

Proposed criteria for resection of pancreatic cystic lesions have included symptoms, size (>3 cm), and suspicious features by endoscopic ultrasound (EUS). The objective of this study was to evaluate risk factors for malignancy in a large series of patients undergoing resection of suspected pancreatic cystic neoplasms.

METHODS

Medical records of patients selected for resection of pancreatic cystic lesions at Duke University Medical Center from 2000 to 2008 were reviewed. Lesions with solid components on cross-sectional imaging were excluded. Malignancy was defined as invasive or in situ carcinoma.

RESULTS

After review, 101 patients were confirmed to have undergone resection for suspected cystic neoplasms of the pancreas. Preoperative EUS was performed in 71 patients. Sixteen patients (16%) had malignant lesions (preoperative size 1.5-5.9 cm). There was no clear association between size and malignancy. Male gender, biliary ductal dilatation (BDD), pancreatic ductal dilatation (PDD), and suspicious cytology (but not age, symptoms, or size) were associated with increased risk of malignancy. When factors available for all patients were incorporated into a multivariate model, only BDD and PDD were independent risk factors for malignancy. Only one patient with malignancy had neither BDD nor PDD but did have solid components by EUS.

CONCLUSIONS

In patients selected for resection, size was not an independent risk factor for malignancy. While size might be appropriate for stratification of asymptomatic patients with simple cysts, size should not be used as a selection criterion for patients who have cysts with solid components or with associated BDD or PDD.

Current trends in pancreatic cystic neoplasms

OBJECTIVE

To define how patients with pancreatic cysts are being diagnosed and treated.

DESIGN

Retrospective case series.

SETTING

University-affiliated tertiary care center.

PATIENTS

Four hundred one patients evaluated in the Department of Surgery between January 2004 and December 2007.

MAIN OUTCOME MEASURES

Clinical management, histological diagnosis, and results of surveillance.

RESULTS

Pancreatic cysts were incidentally discovered in 71% (284 of 401) of patients. There was no statistically significant difference in age (60.4 vs 63.1 years; P = .10), cyst size (31 vs 27 mm; P = .12), or histological diagnosis between symptomatic patients and patients with incidentally discovered cysts. Whereas the majority of symptomatic patients had their cystic neoplasms resected on diagnosis, 50% (142 of 284) of incidentally discovered cysts were initially managed nonoperatively. Of the patients who were managed with surveillance, 13 (8%) subsequently underwent resection after a median of 2.1 years because of an increase in cyst size, development of symptoms, increasing tumor markers, worrisome endoscopic ultrasonography findings, or patient anxiety. The most common diagnosis among resected lesions was either main-duct intraductal papillary mucinous neoplasm (25%) or branch-duct intraductal papillary mucinous neoplasm (23%). Invasive cancer was found in 29 of 256 (11%) resected cystic neoplasms, 9 of which were incidentally discovered, and in 7% (1 of 13) of patients who underwent watchful waiting prior to resection.

CONCLUSIONS

Incidentally discovered pancreatic cystic neoplasms composed 71% of our series, of which 50% were immediately resected. Subsequent morphologic changes or development of symptoms prompted an operation in 8% of patients after a period of surveillance. Invasive malignancy was present in 11% of all resected specimens but in 38% of main-duct intraductal papillary mucinous neoplasms.

Cystic Neoplasms of the Pancreas: Current Diagnostic Modalities and Management

Cystic neoplasm of the pancreas is a relatively uncommon condition covering a wide spectrum of pathology. The increasing incidence as a result of routine imaging tests in asymptomatic patients presents a diagnostic and therapeutic problem to the clinician. This paper discusses the role of the various investigative modalities in the management of cystic neoplasia of the pancreas. Key words: Frantz tumour, Intraductal papillary mucinous neoplasm, Mucinous cystadenoma, Mucinous cystadenocarcinoma, Mucinous neoplasm of the pancreas, Solid pseudopapillary neoplasm

Cystic pancreatic neuroendocrine neoplasms with uncertain malignant potential: report of two cases

Neuroendocrine tumors of the pancreas (NETP) represent only 1%-2% of all pancreatic neoplasms. They can be classified as functioning or non-functioning, respectively, according to the presence or absence of paraneoplastic syndrome. Case 1 concerned a 70-year-old woman with a cystic lesion of the pancreatic head and body. All tumor markers were negative. The patient underwent a distal pancreatectomy. The histology revealed a well-differentiated endocrine tumor with uncertain malignant potential. Case 2 was a 61-year-old man with chronic polyserositis. The serum tumor markers were negative, while he was strongly positive for intracystic tumor markers carcinoembryonic antigen, carbohydrate antigen (CA) 19-9, and CA 125. The patient underwent a cephalo-pancreatic duodenectomy. The preoperative differential diagnosis of cystic NETP is still a challenge due to the high rate of the nonfunctional variant. Although cystic NETPs are well differentiated, they are still tumors with a malignant potential, and therefore an early diagnosis and radical surgical resection could be associated with a better long-term survival.

Current management of cystic neoplasms of the pancreas

Over the last decade there has been a dramatic increase in the number of patients identified with pancreatic cysts. This increase has been largely attributed to advances in imaging. The majority of these cysts represent benign neoplasms; however, a significant fraction of these are pre-malignant or malignant. Because the majority of these neoplasms are benign, many reports have advocated a selective approach to surgical resection. Here we review the literature that has contributed to the development of our approach to the management of these cystic neoplasms. We provide an overview of the key features in diagnosis and in predicting malignancy. Particular attention is given to the natural history and management of intraductal papillary mucinous neoplasms (IPMN).

The additional value of CT images interpretation in the differential diagnosis of benign vs. malignant primary bone lesions with 18F-FDG-PET/CT

OBJECTIVE

To evaluate the value of a dedicated interpretation of the CT images in the differential diagnosis of benign vs. malignant primary bone lesions with 18 fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT).

MATERIALS AND METHODS

In 50 consecutive patients (21 women, 29 men, mean age 36.9, age range 11-72) with suspected primary bone neoplasm conventional radiographs and 18F-FDG-PET/CT were performed. Differentiation of benign and malignant lesions was separately performed on conventional radiographs, PET alone (PET), and PET/CT with specific evaluation of the CT part. Histology served as the standard of reference in 46 cases, clinical, and imaging follow-up in four cases.

RESULTS

According to the standard of reference, conventional 17 lesions were benign and 33 malignant. Sensitivity, specificity, and accuracy in assessment of malignancy was 85%, 65% and 78% for conventional radiographs, 85%, 35% and 68% for PET alone and 91%, 77% and 86% for combined PET/CT. Median SUV(max) was 3.5 for benign lesions (range 1.6-8.0) and 5.7 (range 0.8-41.7) for malignant lesions. In eight patients with bone lesions with high FDG-uptake (SUV(max) >or= 2.5) dedicated CT interpretation led to the correct diagnosis of a benign lesion (three fibrous dysplasias, two osteomyelitis, one aneurysmatic bone cyst, one fibrous cortical defect, 1 phosphaturic mesenchymal tumor). In four patients with lesions with low FDG-uptake (SUV(max) < 2.5) dedicated CT interpretation led to the correct diagnosis of a malignant lesion (three chondrosarcomas and one leiomyosarcoma). Combined PET/CT was significantly more accurate in the differentiation of benign and malignant lesions than PET alone (p = .039). There was no significant difference between PET/CT and conventional radiographs (p = .625).

CONCLUSION

Dedicated interpretation of the CT part significantly improved the performance of FDG-PET/CT in differentiation of benign and malignant primary bone lesions compared to PET alone. PET/CT more commonly differentiated benign from malignant primary bone lesions compared with conventional radiographs, but this difference was not significant.

Management of serous cystadenoma of the pancreas

Serous cystadenoma of the pancreas is a diagnosis being entertained with increasing frequency. The histopathologic findings, diagnostic strategy, differential diagnosis, and treatment strategy of these generally benign but sometimes symptomatic lesions are discussed. Based on the available case series, surgical resection should be considered in good-risk patients with symptomatic tumors, with tumors at least 4 cm in maximum diameter, or in whom a more worrisome diagnosis cannot be excluded.