Endoscopic ultrasound and intraductal ultrasound in the diagnosis of small pancreatic tumors

Controversies in EUS: Do we need miniprobes?

This is the fifth in a series of papers entitled "Controversies in EUS." In the current paper, we deal with high-resolution catheter probes, otherwise known as EUS miniprobes (EUS-MPs). The application of miniprobes for early carcinomas in the entire intestinal tract, for subepithelial lesions, and for findings in the bile duct and pancreatic duct as well as endobronchial use is critically discussed. Submucous lesions, especially in the colon, but also early carcinomas in special cases are considered the most important indications. The argument is illustrated by numerous examples.

Does a family history of pancreatic ductal adenocarcinoma and cyst size influence the follow-up strategy for intraductal papillary mucinous neoplasms of the pancreas?

OBJECTIVE

This study aimed to evaluate the relationship between pancreatic ductal adenocarcinoma (PDAC) family history and PDAC development in patients followed up for intraductal papillary mucinous neoplasms (IPMNs) and to assess the cyst size relevance in determining follow-up strategies.

METHODS

We analyzed 300 patients with branch duct and mixed-type IPMN who were followed up at our facility.

RESULTS

Among the patients aged 70 years or older, the frequency of PDAC did not differ significantly between those with 1 first-degree relative with PDAC and those without a family history. Although patients with IPMNs of greater than or equal to 30 mm were followed up for a significantly shorter duration than those patients with IPMNs of less than 30 mm, the frequency of IPMN progression and malignant IPMN was significantly greater in the former. The frequency of IPMN progression and pancreatic cancer did not differ significantly according to IPMN size (<10, 10-20, and 20-30 mm) in cases without mural nodules.

CONCLUSIONS

Patients with 1 first-degree relative with PDAC can be followed up using the same criteria for patients without a family history. Special attention should be paid to IPMN progression and malignant transformation in patients with IPMNs of greater than or equal to 30 mm, but cyst size need not be considered when determining follow-up strategies for patients with IPMNs of less than 30 mm without mural nodules.

Case report: Intraductal tubulopapillary neoplasm of the pancreas with unique clear cell phenotype

Intraductal tubulopapillary neoplasms of the pancreas are very rare tumors characterized by intraductal tubulopapillary growth, ductal differentiation, scant intracellular mucin production and cellular dysplasia. Here, we report the first case of an intraductal tubulopapillary neoplasm of the pancreas with clear cell morphology. The tumor was detected during the diagnostic work-up of acute pancreatitis in a 43- year old female. Histological examination revealed a tumor with the typical architecture of an intraductal tubulopapillary neoplasm of the pancreas with tumor cells showing abundant clear cytoplasm and Di-PAS negativity. Immunohistochemistry revealed positivity for Pan-CK, CK7, CK8/18, MUC1, MUC6, carbonic anhydrase IX, CD10, EMA, β-catenin and e-cadherin. Sanger sequencing did not detect mutations for β-catenin, BRAF, KRAS, PIK3CA and GNAS. Altogether, histology, immunohistochemical expression profile (MUC1+, MUC6+, MUC2-, MUC5AC-, thrypsin-, chymotrypsin-, CDX2-) and sequencing results led to the diagnosis of intraductal tubulopapillary neoplasm. However, the neoplasm consisted of cells showing abundant clear cytoplasm, a morphological pattern not being described so far in the current classification of pancreatic intraductal neoplasms. Potential differential diagnosis and the molecular basis of clear cell morphology are discussed. In conclusion, we consider this tumor as intraductal tubulopapillary neoplasm of the pancreas with unique clear cell phenotype. After surgery and without adjuvant therapy, the patient’s clinical course has been uneventful for over two years now.

Accuracy of preoperative workup in a prospective series of surgically resected cystic pancreatic lesions

BACKGROUND

Magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS) are considered useful techniques in the evaluation of pancreatic cysts. Aim of this study was to prospectively compare the diagnostic value of these techniques.

METHODS

This study included consecutive patients who underwent MRI, EUS, and EUS-FNA for a pancreatic cyst that was eventually resected surgically. Observers scored for cyst characteristics, a distinction between mucinous and non-mucinous cysts and a suspicion of malignancy. The interobserver agreement between MRI and EUS was calculated.

RESULTS

A total of 32 patients were included. Sensitivity for diagnosing a mucinous cyst was 78% for EUS versus 91% for MRI. Sensitivity for detecting malignancy was 25% (1/4) and 50% (2/4) for EUS and MRI respectively. Sensitivity of EUS-FNA for diagnosing a mucinous cyst (positive cytology and/or CEA >192 ng/ml) was 61%. Sensitivity for detecting malignancy (positive cytology) was 1/4 (25%). Interobserver agreement between MRI and EUS for the features was poor to fair.

CONCLUSION

MRI and EUS are comparable techniques for the morphological characterization of pancreatic cysts. Combined sensitivity of EUS and MRI was higher than the sensitivity of one of the techniques alone. For diagnosing a mucinous cyst, FNA findings showed a low sensitivity, but a high specificity.

Epidemiology, diagnosis, and management of cystic lesions of the pancreas

Although little is known on the true prevalence of pancreatic cysts, physicians are currently more frequently confronted with pancreatic cysts because of the increasing use of sophisticated cross-sectional abdominal imaging. Cystic lesions of the pancreas comprise of a heterogeneous group of diagnostic entities, some of which are benign such as inflammatory pseudocysts or serous cystadenomas and do not require resection when asymptomatic. Others like mucinous cysts or intraductal papillary mucinous neoplasms (IPMN) have a malignant potential and in these cases surgical resection is often indicated. For this reason an adequate distinction between the various cysts is crucial to optimize management strategy. Different diagnostic methods that could be of value in the differentiation include radiologic imaging techniques such as CT, MR, and endosonography. In addition, fluid aspiration for cytopathology, tumormarkers or molecular analysis is widely used. Different guidelines are available but so far no optimal diagnostic algorithm exists. We summarize the epidemiology, classification, clinical presentation, diagnostics, management, and future perspectives.

Current role of imaging methods in the diagnosis of cystic solid pancreas neoplasms: part II

The authors address the value of endoscopic retrograde cholangiopancreatography, ultrasonography, computed tomography, magnetic resonance imaging and endoscopic ultrasound for the diagnosis of cystic and solid neoplasms of the pancreas, demonstrating that each of them is of great importance to undoubtedly increase the diagnostic accuracy of the biliopancreatic system diseases. The best method for each of several tumors is then determined.

Clinical features and natural history of serous cystic neoplasm of the pancreas

AIMS

To clarify the clinical features and the natural history of serous cystic neoplasm (SCN) of the pancreas.

METHODS

We retrospectively analyzed data from 30 patients affected by SCN. SCNs were classified as (1) microcystic type, (2) micro- and macrocystic type, and (3) macrocystic type according to the modified WHO classification. Eighteen patients who underwent serial radiographic imaging were identified, and tumor growth rate in these patients was evaluated.

RESULTS

The median age was 62 years, and the female:male ratio was 2:1. Twenty-five patients (83%) were asymptomatic and 5 (17%) were symptomatic. The median tumor size was 2.6 cm. Fifteen cases (50%) had the microcystic type, 7 (23%) the micro- and macrocystic type, and 8 (27%) the macrocystic type. Age, gender, symptoms, location or tumor size did not differ significantly among the three subtypes. Eighteen patients were followed up for a median of 58 months. Morphological changes were observed in 3 patients (17%) and enlargement of tumor size in 9 patients (50%) during the follow-up. The growth rate was 0.29 cm per year and doubling time was 3.5 years; these rates did not differ among morphological subtypes or size of tumors.

CONCLUSIONS

In asymptomatic patients with a clear imaging diagnosis of SCN, nonoperative management with a careful follow-up should be recommended. Surgery should be suggested in only symptomatic patients, those with giant tumors (>10 cm), rapid growing or when the presence of a potentially malignant tumor cannot be excluded. and IAP.

Role of endoscopic retrograde cholangiopancreatography in pancreatic diseases

Over the last 15 years, endoscopic retrograde cholangiopancreatography (ERCP) has evolved from a diagnostic tool to one that is primarily used to provide therapy. This development occurred first for biliary disorders and subsequently to a lesser extent for pancreatic diseases. Computed tomography, magnetic resonance imaging, magnetic resonance cholangiopancreatography and endoscopic ultrasonography suggest a diagnosis in the majority of patients with pancreatic diseases today and can help physicians and patients avoid unnecessary ERCP. However, a selected number of patients with pancreatic diseases may benefit from pancreatic endotherapy and avoid complex surgery and chronic use of medications. Pancreatic sphincterotomy, pancreatic stenting and pancreatic cyst drainage are some of the most effective and challenging endoscopic pancreatic interventions and should be performed with caution by expert therapeutic endoscopists. There has been a paucity of randomized studies investigating endoscopic techniques in comparison with surgery and medical therapy for the treatment of most benign and malignant pancreatic disorders due to the limited number of patients and the expertise required to attempt these procedures.

Diagnosis of pancreatic tumors by endoscopic ultrasonography

Pancreatic tumors are highly diverse, as they can be solid or cystic, and benign or malignant. Since their imaging features overlap considerably, it is often difficult to characterize these tumors. In addition, small pancreatic tumors, especially those less than 2 cm in diameter, are difficult to detect and diagnose. For characterizing pancreatic tumors and detecting small pancreatic tumors, endoscopic ultrasonography (EUS) is the most sensitive of the imaging procedures currently available. This technique also provides good results in terms of the preoperative staging of pancreatic tumors. EUS-guided fine needle aspiration (EUS-FNA) has also proved to be a safe and useful method for tissue sampling of pancreatic tumors. Despite these advantages, however, it is still difficult to differentiate between benign and malignant, solid or cystic pancreatic tumors, malignant neoplasms, and chronic pancreatitis using EUS, even when EUS-FNA is performed. Recently, contrast-enhanced EUS with Doppler mode (CE-EUS) employing ultrasound contrast agents, which indicate vascularization in pancreatic lesions, has been found to be useful in the differential diagnosis of pancreatic tumors, especially small pancreatic tumors. However, Doppler ultrasonography with contrast-enhancement has several limitations, including blooming artifacts, poor spatial resolution, and low sensitivity to slow flow. Consequently, an echoendoscope was developed recently that has a broad-band transducer and an imaging mode that was designed specifically for contrast-enhanced harmonic EUS (CEH-EUS) with a second-generation ultrasound contrast agent. The CEH-EUS technique is expected to improve the differential diagnosis of pancreatic disease in the future. This review describes the EUS appearances of common solid and cystic pancreatic masses, the diagnostic accuracy of EUS-FNA, and the relative efficacies and advantages of CE-EUS and CEH-EUS along with their relative advantages and their complementary roles in clinical practice.

Role of endoscopic ultrasound in the diagnosis and staging of pancreatic cancer

Early diagnosis of pancreatic cancer remains a difficult task, and multiple imaging tests have been proposed over the years. The aim of this review is to describe the current role of endoscopic ultrasound (EUS) for the diagnosis and staging of patients with pancreatic cancer. A detailed search of MEDLINE between 1980 and 2007 was performed using the following keywords: pancreatic cancer, endoscopic ultrasound, diagnosis, and staging. References of the selected articles were also browsed and consulted. Despite progress made with other imaging methods, EUS is still considered to be superior for the detection of clinically suspected lesions, especially if the results of other cross-sectional imaging modalities are equivocal. The major advantage of EUS is the high negative predictive value that approaches 100%, indicating that the absence of a focal mass reliably excludes pancreatic cancer. The introduction of EUS-guided fine needle aspiration allows a preoperative diagnosis in patients with resectable cancer, as well as a confirmation of diagnosis before chemoradiotherapy for those that are not. This comprehensive review highlighted the diagnostic capabilities of EUS including the newest refinements such as contrast-enhanced EUS, EUS elastography, and 3-dimensional EUS. The place of EUS-guided biopsy is also emphasized, including the addition of molecular marker techniques.

Growth process of small pancreatic carcinoma: A case report with imaging observation for 22 months

This report describes serial observations of the growth process of a small invasive ductal carcinoma (IDC) of the pancreas from imaging studies. Histopathological studies showed IDC with macroscopic retention cysts proximal to an intraductal papillary-mucinous adenoma with mild atypia of the branch duct type in the pancreatic body, with no relation between the two lesions. IDC was demonstrated as an extremely low-echoic mass resembling a cyst with an unclear margin on the initial endoscopic ultrasonography. We misinterpreted the low-echoic mass as a benign intraductal mucinous-papillary neoplasm (IPMN) based on findings of other imaging studies, and the patient was followed-up. The mass increased from 7 mm to 13 mm in diameter over 22 mo, and remained smaller than 10 mm in diameter for about 420 d. The tumor volume doubling time was 252 d. The Ki67 labeling index was 15.9%, similar to that described in previous reports. Hence, IDC may grow slowly while remaining small.

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.

[Intraductal papillary mucinous tumor: diagnostic and therapeutic approach]

Primary cystic pancreatic neoplasms are rare tumors, with an approximate prevalence of 10% of cystic pancreatic lesions. Most of these lesions correspond to mucinous cystic neoplasm, serous cystoadenoma and intraductal papillary mucinous tumor (IPMT). IPMT is characterized by diffuse dilatation of the main pancreatic duct and/or side branches with inner defects related to mucin or tumor, or mucin extrusion from a patent ampulla. IPMT has a low potential for malignancy, with a low growth rate, a low rate of metastatic spread and postsurgical recurrence. Over the last few years, major advances have been made in the diagnostic and therapeutic management of this tumor.

Histopathological study of invasive ductal carcinoma (IDC) of the pancreas without associated cancerous occlusion of the main pancreatic duct

BACKGROUND/PURPOSE

[corrected] Invasive ductal carcinoma (IDC) of the pancreas may be associated with cancerous occlusion of the main pancreatic duct (MPD) in its growth process, but at quite low a frequency; there are patients who do not develop this occlusion.

METHODS

This study examined the histological features of surgical specimens from 8 patients with IDC without MPD occlusion, in comparison to 32 patients with IDC with this occlusion (controls). The pancreatic duct was identified by confirming the presence of mural elastic fibers on the wall of the pancreatic duct. Immunohistochemical staining was done with Ki-67 antibody.

RESULTS

The frequency of IDC without MPD occlusion was very low (5.0% [2/40] patients at Kurume University and 3.1% [4/126] patients at Juntendo University). The number of intraductal carcinoma components was 1.5 +/- 1.1 per specimen in the IDCs without occlusion and 5.9 +/- 2.4 in the controls (P < 0.001). The Ki-67 labeling index was 18.0 +/- 11.7% in the IDCs without occlusion and 30.0 +/- 12.1% in the controls (P < 0.05). The number of intraductal carcinoma components and the Ki-67 labeling index were significantly lower in the IDCs without occlusion than in the controls.

CONCLUSIONS

Our findings suggested that these two types of IDC could have different biological features.

[Intraductal papillary mucinous tumors of the pancreas]

Reports of intraductal papillary mucinous tumors of the pancreas have become substantially more frequent in the literature in the past several years. This increased prevalence is due, among other things, to improved screening techniques, especially high-resolution spatial imaging. These tumors are characterized by proliferation of the intraductal epithelium, mucin production, and ductal dilatation. They grow slowly. Their potential for malignancy is high (although the precise risk remains difficult to assess), but their prognosis, when identified during the first stage of neoplastic transformation (before invasion), is far better than that of 'pancreatic ductal adenocarcinoma. Early diagnosis allows patients to be treated before carcinomatous degeneration. Specific diagnosis makes it possible to define an appropriate treatment strategy - either surgery or monitoring, especially when only the intralobular ducts are affected. In that case, the risk of malignant degeneration is much lower than with lesions in the pancreatic duct or in combined forms.

Nonoperative imaging techniques in suspected biliary tract obstruction

Evaluation of suspected biliary tract obstruction is a common clinical problem. Clinical data such as history, physical examination, and laboratory tests can accurately identify up to 90% of patients whose jaundice is caused by extrahepatic obstruction. However, complete assessment of extrahepatic obstruction often requires the use of various imaging modalities to confirm the presence, level, and cause of obstruction, and to aid in treatment plan. In the present summary, the literature on competing technologies including endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiopancreatography (PTC), endoscopic ultrasound (EUS), intraductal ultrasonography (IDUS), magnetic resonance cholangiopancreatography (MRCP), helical CT (hCT) and helical CT cholangiography (hCTC) with regards to diagnostic performance characteristics, technical success, safety, and cost-effectiveness is reviewed. Patients with obstructive jaundice secondary to choledocholithiasis or pancreaticobiliary malignancies are the primary focus of this review. Algorithms for the management of suspected obstructive jaundice are put forward based on current evidence. Published data suggest an increasing role for EUS and other noninvasive imaging techniques such as MRCP, and hCT following an initial transabdominal ultrasound in the assessment of patients with suspected biliary obstruction to select candidates for surgery or therapeutic ERCP. The management of patients with a suspected pancreaticobiliary condition ultimately is dependent on local expertise, availability, cost, and the multidisciplinary collaboration between radiologists, surgeons, and gastroenterologists.

Serous cystadenoma of the pancreas: tumor growth rates and recommendations for treatment

OBJECTIVE

To define the natural history and optimal management of serous cystadenoma of the pancreas.

SUMMARY BACKGROUND DATA

Serous cystadenoma of the pancreas is the most common benign pancreatic neoplasm. Diagnostic criteria, potential for growth or malignancy, and outcomes are not well defined. As a result, management for patients with serous cystadenomas varies widely in current practice.

METHODS

A total of 106 patients presenting with serous cystadenoma of the pancreas from 1976-2004 were identified. Hospital records were evaluated for patient and tumor characteristics, diagnostic workup, treatment, and outcome. Twenty-four patients with serial radiographic imaging were identified, and tumor growth curves calculated.

RESULTS

Mean age at presentation was 61.5 years and 75% of patients were female. The most common symptoms were abdominal pain (25%), fullness/mass (10%), and jaundice (7%); 47% were asymptomatic. Mean tumor diameter was 4.9 +/- 3.1 cm, which did not vary by location. Tumors <4 cm were less likely to be symptomatic than were tumors > or =4 cm (22% vs. 72%, P < 0.001). The median growth rate in the patients who had serial radiography was 0.60 cm/y. For tumors <4 cm at presentation (n = 15), the rate was 0.12 cm/y, whereas for tumors > or =4 cm (n = 9), the rate was 1.98 cm/y (P = 0.0002). Overall, 86 patients underwent surgery, with one perioperative death.

CONCLUSIONS

Large (>4 cm) serous cystadenomas are more likely to be symptomatic. Although the median growth rate for this neoplasm is only 0.6 cm/y, it is significantly greater in large tumors. Whereas expectant management is reasonable in small asymptomatic tumors, we recommend resection for large serous cystadenomas regardless of the presence or absence of symptoms.

Prospective evaluation of a jelly-like conducting medium for catheter US probe imaging of esophageal and duodenal lesions

BACKGROUND

The catheter probe EUS(C-EUS) relies on luminal water for acoustic coupling. However, in tubular structures, such as the esophagus and the duodenum, instilled water drains away rapidly. The use of water-filled balloons is limited by air artifact and other problems. This study evaluated the image quality, the penetration depth, the tumor staging accuracy, and the safety of C-EUS by using carboxymethylcellulose, an edible, nontoxic, transparent jelly-like substance (JC-EUS).

METHODS

Forty patients with an esophageal or a duodenal submucosal lesion or an esophageal carcinoma were evaluated prospectively in a crossover study with both C-EUS and JC-EUS when using a 12-MHz US catheter probe. Based on still images, depth of US penetration and image quality (by using a predefined 1 to 5 scale) were assessed by a blinded, independent endosonographer.

OBSERVATIONS

JC-EUS was superior in image quality compared with C-EUS overall (mean score: 4.9 vs. 2.6; p <0.001), as well as in each subgroup (esophageal carcinoma, esophageal submucosal lesion, duodenal submucosal lesion). Penetration depth was not significantly different (2.5 cm). Staging was 100% accurate in 14 patients with esophageal cancer who underwent surgery. There was no procedure-related complication.

CONCLUSIONS

JC-EUS is safe, provides superior image quality to C-EUS, and is accurate for local staging of esophageal cancer.

Pancreatic neoplasms

Patients who present with signs and symptoms suggesting a pancreatic neoplasm typically undergo initial imaging with transabdominal ultrasound or CT. When a pancreatic mass or fullness is identified, it may represent an inflammatory mass, benign process, or malignancy. Endoscopic ultrasound (EUS) is performed commonly to further characterize the lesion, obtain a tissue diagnosis, and for staging. This article reviews the role of EUS for the diagnosis and staging of pancreatic tumors.

Improved targeting of pancreatic cancer: experimental studies of a new bispecific antibody, pretargeting enhancement system for immunoscintigraphy

PURPOSE

The early detection and diagnosis of pancreatic cancer remains a major clinical challenge in which imaging procedures have a central role. The purpose of this study was to evaluate a pretargeting method with a bispecific PAM4 (bsPAM4; anti-MUC1) antibody for radioimmunoscintigraphy of experimental human pancreatic cancer.

EXPERIMENTAL DESIGN

A bispecific F(ab')(2) antibody was generated from chimeric PAM4 Fab' and murine 734 (anti-indium-diethylenetriaminepentaacetic acid) Fab' fragments and then used in conjunction with 2 peptide haptens ((111)In-IMP-156 and (99m)Tc-IMP-192). Biodistribution studies and radioimmunoscintigraphic imaging properties of the radiolabeled bsPAM4, and pretargeted, radiolabeled peptides were examined in the CaPan1 human pancreatic tumor grown as s.c. xenografts in athymic nude mice. Tumor uptake and tumor:nontumor ratios were compared with a nontargeting irrelevant anti-CD20, bispecific rituximab, radiolabeled peptides alone, and with directly labeled PAM4.

RESULTS

Biodistribution results indicated significantly greater tumor uptake of radiolabeled peptides at 3 h after injection when pretargeting was performed with bsPAM4 as compared with the bispecific rituximab [20.2 +/- 5.5 percentage of injected dose per gram of tissue (%ID/g) versus 0.9 +/- 0.1%ID/g, respectively, for (111)In-IMP-156, and 16.8 +/- 4.8%ID/g versus 1.1 +/- 0.2%ID/g, respectively, for (99m)Tc-IMP-192]. Similar results were obtained at the 24-h time point. Tumor:nontumor ratios were >30 for all of the tissues except the kidneys, where a ratio of 7.8 +/- 2.8 was observed. By immunoscintigraphy, tumors could be visualized as early as 30 min after injection of the radiolabeled peptide.

CONCLUSIONS

These studies demonstrate the feasibility of using the pretargeted, bispecific antibody technology for nuclear imaging of pancreatic cancer. The advantage of pretargeted bsPAM4 antibody as an imaging platform is the high specificity for pancreatic cancer as compared with the physicochemical parameters identified by current imaging technologies.

Imaging and Percutaneous Management of Acute Complicated Pancreatitis

Acute pancreatitis varies from a mild, self-limited disease to one with significant morbidity and mortality in its most severe forms. While clinical criteria abound, imaging has become indispensable to diagnose the extent of the disease and its complications, as well as to guide and monitor therapy. Percutaneous interventional techniques offer options that can be life-saving, surgery-sparing or important adjuncts to operation. Close cooperation and communication between the surgeon, gastroenterologist and interventional radiologist enhance the likelihood of successful patient care.

Evaluation and management of cystic pancreatic tumors: emphasis on the role of EUS FNA

Cystic lesions of the pancreas are increasingly recognized and usually represent pseudocysts or cystic pancreatic tumors (CPTs), but also include congenital cysts, acquired cysts, extrapancreatic cysts, or cystic degeneration of solid tumors. It is important to distinguish CPT lesions given their varied prognosis and therapy. Mucinous varieties of CPTs (mucinous cystic neoplasms and intraductal papillary mucinous tumors) are premalignant or malignant, and surgical resection is generally recommended in good operative candidates. In contrast, nonmucinous CPTs include serous cystadenomas with a very low malignant potential, or pseudocysts, which are always benign. As a result, nonmucinous CPTs are generally resected only when inducing symptoms or complications. Review of the clinical, imaging, laboratory, and pathology information may clarify the specific tumor type. The relatively limited accuracy of any one modality requires that we consider the combined results when making management decisions.

EUS in the evaluation of pancreatic cystic lesions

BACKGROUND

The differential diagnosis in pancreatic cystic lesions is often difficult despite the availability of various modern imaging modalities. This study assessed the role of EUS in the following: (1) discrimination of pseudocysts from pancreatic cystic tumors, (2) differential diagnosis between serous cystadenoma and mucinous cystic tumor, and (3) prediction of accompanying malignancy in intraductal papillary mucinous tumor.

METHODS

EUS findings in 75 patients with pancreatic cystic lesions (58 cystic tumors, 17 pseudocysts) were evaluated. In the comparison of pseudocysts and cystic tumors, the latter included intraductal papillary mucinous tumor, mucinous cystic tumors, and serous cystadenomas, but not solid-pseudopapillary tumors.

RESULTS

In univariate analysis, pseudocysts exhibited echogenic debris and parenchymal changes more often than cystic tumors did (respectively, 29% vs. 6%, p < 0.05; and 65% vs. 4%, p < 0.001). In contrast, septa and mural nodules were found more frequently in cystic tumors than pseudocysts (respectively, 69% vs. 12%, p < 0.001; 56% vs. 12%, p < 0.01). Multivariate analysis revealed that parenchymal changes (odds ratio [OR] = 83.59; p < 0.01); septa (OR = 30.75; p < 0.05); and mural nodules (OR = 21.38; p < 0.05) were independent predictors of differentiation between pseudocysts and cystic tumors. Serous cystadenoma exhibited diverse EUS features, as well as a honeycomb appearance. Mural nodules were found more often in mucinous cystic tumors than in serous cystadenomas (p < 0.05). There were no factors that predicted malignancy in intraductal papillary mucinous tumor.

CONCLUSIONS

EUS is a useful complementary imaging method for differentiation of pancreatic cystic lesions.

The role of ultrasound in biliary and pancreatic diseases

The possibilities and the limits of transabdominal ultrasonography (US) in the diagnosis of bilio-pancreatic diseases are reviewed here in the light of the last 10 years' research. US remains the method of choice for the diagnosis of gallstones and is generally accepted as an initial imaging technique in gallstone complications, such as acute cholecystitis. Moreover the method can be useful for the detection of the biliary complications after laparoscopic cholecystectomy and after liver transplantation. US is still considered the first diagnostic procedure when stones are suspected in the common bile duct. The use of color Doppler can provide a differential diagnosis of gallbladder cancer with respect to other benign inflammatory or polypoid lesions. Color Doppler US allows to detect vascular complications of acute pancreatitis such as pseudoaneurysms. US is still considered useful for the initial screening of the pancreatic cancer. However, for staging other imaging techniques must be employed. With US useful informations are obtained in the diagnosis of cystic tumors of the pancreas and of pancreatic metastases. US is generally of little use for the diagnosis of endocrine tumors.

Pancreatic carcinomas smaller than 3.0 cm: endosonography (EUS) in diagnosis, staging and prediction of resectability

BACKGROUND

The size of a pancreatic carcinoma determines prognosis and resection. The aim of this study was to review our clinical experience with endoscopic ultrasound (EUS) in diagnosing and staging pancreatic tumours <3.0 in diameter.

METHODS

From February 1997 to October 2000 medical records and results of abdominal ultrasound (US), spiral computed tomography (CT) and EUS with fine-needle aspiration biopsy (FNA) were reviewed in 17 patients operated for histologically proven pancreatic adenocarcinoma measuring <or= 3.0 cm in diameter. The mean age of the patients was 64 years (range 42-76 years).

RESULTS

US identified a pancreatic lesion in 11/17 (65%) patients. Spiral CT showed a total of 16/17 (94%) patients with a lesion. EUS identified pancreatic tumour in all patients (100%), and tissue was obtained from 15/17 patients (88%). Mean tumour size was 2.5 cm (range 0.8-3.0 cm). EUS accuracy in evaluating the portal vessels was 78%, superior mesenteric artery 100%, tumour stage (T) 88%, isolated node stage (N) 65% and combined TN staging was 53%. Regarding resectability, EUS sensitivity was 88%, specificity 89%, negative predictive value 89%, positive predictive value 88% and accuracy 88%. Besides cytological material, EUS-FNA histological diagnosis was possible in 12/17 patients (71%). There was only one case of mild post-procedure acute pancreatitis.

CONCLUSION

EUS-FNA is safe and has high diagnostic (100%) and local staging (88%) accuracy in pancreatic cancers <3.0 cm in diameter.

Diagnosis of cystic neoplasms with endoscopic ultrasound

From the data that are currently available, it appears that EUS can help to reliably distinguish between the majority of benign and neoplastic cystic lesions. In equivocal cases, or cases where a high suspicion for malignancy exists, the use of EUS-guided FNA for obtaining cytology and cystic fluid for analysis of various tumor markers, gives the best diagnostic yield. Occasionally, despite a complete evaluation of a cystic mass, the cyst type may not be determined. The decision regarding further management of these lesions should be based on a combination of factors including symptoms, cyst size, EUS morphology and the patient's overall medical condition. In the case of symptomatic, large, or suspicious lesions where the patient is a good surgical candidate, surgical resection should be performed. However, it becomes more difficult in the case of asymptomatic, small cystic lesions where the patient is not an optimal surgical candidate. In the latter scenario, applying EUS criteria for follow-up of small pancreatic cystic lesions as reported by Ikeda et al can help in the decision-making process. In this study, Ikeda et al reported on 31 patients with pancreatic cystic lesions of unknown etiology that were followed-up with semi-annual EUS exams over a 3-year period. In 87.1% of these lesions, the size was less than 2 cm. Their criteria included 1) a clear thin wall, 2) smooth contour, 3) round or oval shape, 4) no septum or nodules, 5) asymptomatic clinical presentation, and 6) no findings of chronic pancreatitis. The cystic lesions remained stable in 30/31 patients, and only one lesion increased in size. This lesion was resected and was found to be a retention cyst. We are optimistic that the role of EUS in the management of cystic neoplasms will continue to evolve and expand as future studies evaluate the clinical utility of imaging modalities for the optimal practice algorithm for managing these neoplasms.

Timing and extent of surgical intervention in patients from hereditary pancreatic cancer kindreds

Our knowledge of the molecular and genetic etiology of hereditary pancreatic cancer has expanded considerably and is steadily increasing. However, there are only a few hard data available regarding the clinical and surgical management of these patients. Surgery is currently performed when we detect dysplastic changes in the pancreas or when cancer is suspected. Of the available diagnostic modalities, endoscopic ultrasonography has proven so far to be the most useful for detecting dysplastic changes in the pancreases of patients from hereditary pancreatic cancer kindreds. It seems reasonable, once dysplasia has been diagnosed in a high-risk patient, to proceed to total pancreatectomy. The multifocal nature of dysplastic lesions precludes any type of operation that would leave behind pancreatic tissue. Currently, prophylactic whole-organ resection in the absence of premalignant lesions cannot be recommended since we do not know the exact risk for the development of cancer.

Early detection of pancreatic carcinoma

The poor prognosis and late presentation of pancreatic cancer patients emphasize the importance of an effective early detection strategy for patients at risk of developing pancreatic cancer. In current practice, the use of CA 19-9 levels and imaging techniques is not optimal for detecting small pancreatic lesions. It is hoped that the understanding of genetic alterations in combination with the development of high-throughput sensitive techniques will lead to the rapid discovery of a panel of biomarkers that will save lives by enabling aggressive therapy at the time when tumors are curable.

Pancreas: imaging diagnosis with color/power Doppler ultrasonography, endoscopic ultrasonography, and intraductal ultrasonography

Recent advances of ultrasound imaging have made possible to depict various diseases and conditions of the pancreas. Color/power Doppler ultrasonography, endoscopic ultrasonography, and intraductal ultrasonography are feasible to show vascular abnormalities, differentiate the solid and cystic tumors, decide tumor extent, and help to perform interventional treatments of the pancreatic diseases. Those techniques will contribute to the more precise and easier diagnosis and to prompt decision of the treatments of the pancreatic disorders. Radiologists should recognize the diagnostic feasibility and limitations of those techniques in order to avoid unnecessary examinations on the patients, and obtain precise diagnostic images.

Imaging of esophageal tumors with a water-filled condom and a catheter US probe

BACKGROUND

High-frequency catheter ultrasound (C-EUS) probes provide high resolution images of the gastrointestinal tract. Their use in the esophagus is limited by the requirement for a water-filled lumen for good acoustical coupling. We have developed a system using a condom that provides a continuous column of water for high resolution C-EUS imaging of the esophagus.

METHODS

Nine patients underwent condom C-EUS for evaluation of esophageal mucosal and submucosal tumors. A standard latex condom was attached to a 2-channel endoscope and filled with water after esophageal intubation. A 20 MHz C-EUS probe placed within the water-filled condom was used to characterize all lesions.

RESULTS

The condom C-EUS system provided a 360 degree, high resolution image throughout the length of the esophagus without air artifact and without the risk of aspiration associated with filling the esophageal lumen with water. Complete imaging of the tumor was obtained in all cases, and no additional C-EUS procedures were required. The condom C-EUS was subjectively rated superior overall in comparison to standard C-EUS by 4 independent endosonographers.

CONCLUSIONS

Condom C-EUS is a new method of high resolution imaging of the esophagus. This method provides a contained column of water within the esophagus that improves image quality and ease of use and may reduce the risk of aspiration.

Endoscopic ultrasound characteristics of mucinous cystic neoplasms of the pancreas

OBJECTIVE

Mucinous cystic neoplasms of the pancreas have a more favorable prognosis than ductal adenocarcinoma. Management of a subgroup, intraductal papillary-mucinous neoplasms, is controversial. Endoscopic ultrasound (EUS) with fine-needle aspiration biopsy may emerge as the imaging modality of choice. There are few studies describing the EUS features of these tumors.

METHODS

A total of 35 consecutive cases of cystic tumors of the pancreas with an established pathological diagnosis were analyzed for characteristic EUS features.

RESULTS

Mucinous cystadenocarcinomas (n = 14) were more likely to be characterized by hypoechoic cystic/solid mass or complex cyst and were frequently associated with a dilated main pancreatic duct. Benign mucinous duct ectasia (n = 6) were characterized by a dilated main pancreatic duct in conjunction with hyperechoic thickening of the duct wall. The two cases of intraductal mucinous hyperplasia additionally showed a hypoechoic mass. Intraductal papillary carcinoma (n = 11) had features in common with mucinous cystadenocarcinoma but also had echogenic foci in the mass and intraductal hyperechoic lesions. The two cases of microcystic cystadenoma showed either a mixed hypoechoic solid/cystic mass or a complex cyst without the additional features seen in mucinous cystadenocarcinoma.

CONCLUSIONS

EUS features seem to exist that may help to differentiate cystic neoplasms from adenocarcinoma of the pancreas and, thus, to establish the preoperative diagnosis of cystic tumors of the pancreas.

Pancreatic imaging. New modalities

This article discusses the techniques and applications of the newest pancreatic cross-sectional imaging modalities. The specific modalities that are discussed include helical computed tomography with dual phase imaging and three-dimensional computer rendering techniques, magnetic resonance imaging and magnetic resonance cholangiopancreatography, endoscopic and intraductal pancreatic sonography, and radionuclide scintigraphy using positron emission scanning and somatostatin-receptor imaging.