Cystic tumors of the pancreas: evaluation by ultrasonography and computed tomography

Pancreatic mesothelial cyst

A 60-year-old woman was investigated for abdominal pain and increasing asthenia. Abdominal CT revealed a 25 mm hypodense cystic lesion in the tail of the pancreas. MRI showed a multiloculated cystic lesion, T1-hypointense and T2-hyperintense lesion, without wall enhancement. Endoscopic ultrasound detected a 25 mm multi-loculated cystic lesion, with regular margin and without pancreatic duct communication. Diagnosis of pancreatic mucinous cystadenoma was discussed and the patient was referred to surgery. She underwent distal pancreatectomy with spleen preservation. Pathological examination revealed the diagnosis of pancreatic mesothelial cyst. Histologically, the cyst was multiloculated, lined by cuboidal epithelium, ovoid nuclei and amphophilic cytoplasm, without mucin deposition or cytological atypia. Immunohistochemistry examination revealed positive staining for cytokeratin 5/6, vimentin and calretinin. At 1-year follow-up, she is in her usual health, without any symptoms.

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.

Radiology of pancreatic neoplasms: An update

Diagnostic imaging is an important tool to evaluate pancreatic neoplasms. We describe the imaging features of pancreatic malignancies and their benign mimics. Accurate detection and staging are essential for ensuring appropriate selection of patients who will benefit from surgery and for preventing unnecessary surgeries in patients with unresectable disease. Ultrasound, multidetector computed tomography with multiplanar reconstruction and magnetic resonance imaging can help to do a correct diagnosis. Radiologists should be aware of the wide variety of anatomic variants and pathologic conditions that may mimic pancreatic neoplasms. The knowledge of the most important characteristic key findings may facilitate the right diagnosis.

[Pancreatic ultrasonography]

Despite the recent technological advances in imaging, abdominal ultrasonography continues to be the first diagnostic test indicated in patients with a suspicion of pancreatic disease, due to its safety, accessibility and low cost. It is an essential technique in the study of inflammatory processes, since it not only assesses changes in pancreatic parenchyma, but also gives an indication of the origin (bile or alcoholic). It is also essential in the detection and tracing of possible complications as well as being used as a guide in diagnostic and therapeutic punctures. It is also the first technique used in the study of pancreatic tumors, detecting them with a sensitivity of around 70% and a specificity of 90%.

Cystic pancreatic lesions: current evidence for diagnosis and treatment

Pancreatic cystic neoplasms are detected at an increasing frequency due to an increased use and quality of abdominal imaging. There are well known differential diagnostic difficulties concerning these lesions. The aim is to review current literature on the diagnostic options and the following treatment for cystic lesions in the pancreas focusing on serous cystadenomas, primary mucinous neoplasm of the pancreas and mucinous cystadenocarcinomas, as well as intraductal papillary mucinous neoplasms, starting with excluding pseudocysts. A conservative approach is feasible in patients with a clinical presentation suggestive of an asymptomatic serous cystadenoma. Surgical management, as well as follow-up, is discussed for each of the types of neoplastic lesions, including an uncharacterized cyst, based on patient data, symptoms, serum analysis, cyst fluid analysis and morphological features. Aspects for future diagnostics and management of these neoplasia are commented upon.

The application value of contrast-enhanced ultrasound in the differential diagnosis of pancreatic solid-cystic lesions

OBJECTIVE

To retrospectively determine the accuracy of baseline ultrasound (BUS) and of contrast-enhanced ultrasound (CEUS) in the differential diagnosis of pancreatic solid-cystic lesions.

METHODS

Fifty-four pancreatic solid-cystic lesions in 52 patients were examined with BUS and CEUS, two different seniority radiologists read the images independently, Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic value of BUS and CEUS in the diagnosis of benign or malignant pancreatic solid-cystic lesions, the diagnostic consistency between different seniority radiologists was evaluated by Kappa statistics.

RESULTS

Among the 54 lesions, there were pancreatic cyst five cases, pancreatic pseudocyst twenty cases, pancreatic cystadenoma eight cases, pancreatic cystadenocarcinoma seven cases, intraductal papillary mucinous neoplasm of pancreas (IPMN) three cases, pancreatic carcinoma combined liquefied six cases, solid-pseudopallary tumor of pancreas (SPTP) three cases, pancreatic myopericytoma one case, pancreatic lymphangioma one case. After ROC analysis, the areas under the ROC curve (Az) were 0.752 by BUS, 0.928 by CEUS to resident radiologist, and 0.896 by BUS, 0.954 by CEUS to staff radiologist. The correct diagnosis rate of specific disease was 42.6% by BUS, 64.8% by CEUS to staff radiologist (P<0.05), and 33.3% by BUS, 53.7% by CEUS to resident radiologist (P<0.05). The interobserver agreement in CEUS is higher than that in BUS, the Kappa value was 0.889 ± 0.062 and 0.428 ± 0.126 respectively.

CONCLUSION

Compared with BUS, CEUS can significantly enhance the diagnostic rate of pancreatic solid-cystic lesions.

Transabdominal contrast-enhanced ultrasonography of pancreatic cancer

Since its introduction, contrast-enhanced ultrasonography (CEUS) has significantly extended the value of ultrasonography (US). CEUS can be used to more accurately determine pancreatic lesions compared to conventional US or to characterize lesions already detectable by US. Thus, CEUS can aid in the differential diagnosis of pancreatic tumors. Using US contrast media, it is possible to visually detect microvessels in the majority of pancreatic ductal adenocarcinomas. Thus, the use of quantitatively evaluated transabdominal CEUS can help in the differentiation of patients with mass-forming pancreatitis from patients with pancreatic adenocarcinomas. In neuroendocrine pancreatic tumors, different enhancement patterns can be observed in relation to the tumor mass: larger ones show a rapid early enhancement sometimes combined with necrotic central structures, and smaller ones disclose a capillary-blush enhancement. Pseudocysts, the most widespread cystic lesions of the pancreas, are not vascularized. They do not show any signal in CEUS and remain entirely anechoic in all phases, while true cystic pancreatic tumors usually have vascularized septa and parietal nodules. In summary, CEUS is effective for differentiating solid pancreatic tumors in most cases. CEUS is safe and cost effective and can better discriminate solid from cystic pancreatic lesions, thereby directing further imaging modalities.

Contrast-enhanced ultrasound of the pancreas

The introduction of contrast-enhanced ultrasonography (CEUS) has led to major improvements in the diagnostic capabilities of ultrasound (US). The innovative use of CEUS for study of the pancreas has created the need for a definition of the most frequent dynamic features of solid and cystic masses. CEUS is less expensive compared to computed tomography and magnetic resonance imaging and is able to significantly improve the accuracy of US, allowing better characterization and staging of pancreatic pathologies.

Contrast-enhanced ultrasonograpic findings in pancreatic tumors

OBJECTIVE

The purpose of this article is to present the potentials and limits of contrast-enhanced ultrasonography (CEUS) in the characterization of pancreatic tumors, usually hypoechoic or cystic at B-mode ultrasound.

CONCLUSION

As regards hypoechoic lesions at B-mode ultrasound, CEUS often can distinguish among adenocarcinoma, islet cell tumor and serous microcystic adenoma. As regards cystic lesions, CEUS in most cases doesn't add significative diagnostic information; therefore CT, MR or endoscopic US are almost always necessary for their proper characterization.

Ultrasonography of the pancreas. 4. Contrast-enhanced imaging

The introduction of contrast-enhanced ultrasonography (CEUS) has lead to great developments in the diagnostic capabilities of ultrasound. Second generation contrast media, characterized by harmonic responses at low mechanical index of the ultrasound beam, have already proven usefulness in the study of the liver but other abdominal organs can take advantage from the dynamic study during continuous ultrasonographic scans. The dynamic observation of the enhancement allows the perfect evaluation of the abdominal organs perfusion. The perfusion of the pancreas is well correlated to the semeiology of the gland parenchymography at CEUS. The study of the pancreas is a new and promising application of CEUS. CEUS can be used to better identify pancreatic lesions respect to conventional Ultrasound (US) or to characterize pancreatic lesions already visible at US. Moreover the staging of some pancreatic lesions can be improved by the use of contrast media. This article will review the clinical application of CEUS in the different pancreatic pathologies.

Mesothelial cyst of the pancreas

Cystic lesions of the pancreas are increasingly identified because of advances in imaging techniques. The cystic lesions are of different types and are classified as neoplastic, nonneoplastic, and developmental types. Identification of the nature of these cystic lesions is very important because the course and treatment of disparate types of cysts are different. Here, we describe, for the first time, mesothelial cyst involving the pancreas in a 36-year-old man. Distal pancreatectomy showed a 3-cm unilocular cyst containing clear fluid. The cyst was lined by flat to cuboidal epithelium surrounded by fibrous tissue. The lining epithelial cells were positive for vimentin, thrombomodulin, cytokeratin 5/6, and calretinin, thus confirming the mesothelial nature of the cells.

Cystic tumors of the pancreas

Cystic tumors of the pancreas are less frequent than solid lesions and are often detected incidentally, as many of these lesions are small and asymptomatic. However, they may be associated with pancreatitis or have malignant potential. With advancements in diagnostic imaging, cystic lesions of the pancreas are being detected with increasing frequency. Many lesions can cause a pancreatic cyst, most being non-neoplastic while approximately 10% are cystic tumors, ranging from benign to highly malignant tumors. With increasing experience it is becoming clear that the prevalence of pseudocyst among cystic lesions of the pancreas is lower than usually presumed. A presumptive diagnosis of pseudocyst based on imaging appearance alone can cause a diagnostic error, and neoplastic cysts of the pancreas are particularly susceptible to this misdiagnosis, which can result in inappropriate treatment. Cystic tumors of the pancreas are formed by serous or mucinous structures showing all stages of cellular differentiation. According to the WHO classification, they can be subdivided on the basis of their histological type and biological behavior into benign tumors, borderline tumors, and malignant tumors. Cystic pancreatic tumors can be subdivided into peripheral (serous cystadenomas, mucinous cystic tumors, solid and papillary epithelial neoplasms, cystic islet cell tumors), which do not communicate with the main pancreatic duct, and ductal tumors (mucinous tumor), according to their site of origin. On the basis of imaging criteria alone, it can be very difficult to differentiate non-tumoral cystic lesions from neoplastic ones. The management of these patients is complex, and it is important to correlate imaging findings with knowledge of the patient’s symptoms and of the natural history and predictors of malignancy in pancreatic cysts.

Echo-enhanced ultrasound with pulse inversion imaging: A new imaging modality for the differentiation of cystic pancreatic tumours

AIM: To describe and discuss echo-enhanced sonography in the differential diagnosis of cystic pancreatic lesions.

METHODS: The pulse inversion technique (with intravenous injection of 2.4 mL SonoVue^®) or the power-Doppler mode under the conditions of the 2^nd harmonic imaging (with intravenous injection of 4 g Levovist^®) was used for echo-enhanced sonography.

RESULTS: Cystadenomas frequently showed many vessels along fibrotic strands. On the other hand, cystadenocarcinomas were poorly and chaotically vascularized. ”Young pseudocysts” were frequently found to have a highly vascularised wall. However, the wall of the ”old pseudocysts” was poorly vascularized. Data from prospective studies demonstrated that based on these imaging criteria the sensitivities and specificities of echo-enhanced sonography in the differentiation of cystic pancreatic masses were > 90%.

CONCLUSION: Cystic pancreatic masses have a different vascularization pattern at echo-enhanced sonography. These characteristics are useful for their differential diagnosis, but histology is still the gold standard.

Differentiation of cystic pancreatic neoplasms and pseudocysts by conventional and echo-enhanced ultrasound

BACKGROUND AND AIMS

Echo-enhanced sonography is a non-invasive and increasingly used procedure for the differentiation of pancreatic tumors. However, the diagnostic accuracy of this procedure compared to conventional ultrasound for the differential diagnosis of cystic pancreatic neoplasms from pseudocysts has never been investigated in a prospective study.

METHODS

Thirty-one patients with a cystic pancreatic lesion at the conventional ultrasound (mean age 57 years, range 36-82 years) were included in the study. Sonography was performed by an experienced examiner who was unaware of the patients' clinical diagnosis. The exact diagnosis was based on histological evidence from biopsy examination (surgical or transabdominal fine needle biopsy for all cystic neoplasms and five pseudocysts), or a follow-up of at least 18 months (four pseudocysts).

RESULTS

Of the 31 patients, 19 had cystadenomas, three had cystadenocarcinomas, and nine had pseudocysts. Only 27% of the cystadenomas and 67% of the pseudocysts could be correctly classified by conventional ultrasound. Conversely, 95% of the cystadenomas (P = 0.0001) and all pseudocysts were diagnosed correctly by echo-enhanced sonography. The sensitivity of echo-enhanced sonography with respect to diagnosing cystadenoma was 95% and its specificity was 92%. The corresponding values for pseudocysts were both 100%.

CONCLUSION

Echo-enhanced sonography has a high sensitivity and specificity in the differential diagnosis of cystic pancreatic tumors. With this procedure the differentiation of cystadenomas and pseudocysts can be improved. However, histology is the standard of reference.

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.

Imaging of cystic diseases of the pancreas

Although the majority of cystic lesions of the pancreas seen in clinical practice represent postinflammatory pseudocysts, it is important for the radiologist to be knowledgeable of the wide spectrum of cystic masses of the pancreas and the variable prognoses they possess. As a result of similarities in the imaging features of these lesions, a definitive diagnosis is often not possible. By combining imaging features with clinical history, a reasonable differential diagnosis can be offered to the referring physician. In some cases, biopsy or fluid aspiration may be required prior to surgery. In a patient without the appropriate history of pancreatitis and the presence of a cystic pancreatic mass, it is incumbent upon the radiologist to offer alternative diagnoses of cystic neoplasms of the pancreas.

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.

Pancreatic ultrasonography

Pancreatic abnormalities usually are detected on US when it is used for screening patients with abdominal pain and for assessment of the gallbladder and bile ducts. Pancreatic visualization is limited by bowel gas, but with experienced sonographers and newer techniques, including harmonic imaging and oral contrast US, diagnosis of pancreatic abnormalities has significantly improved compared with earlier reports. Appropriate initial diagnosis by US can tailor further investigation, and US-guided biopsy may establish definitive diagnosis.

Characterization of cystic tumors of the pancreas: CT accuracy

PURPOSE

The purpose of this work was to evaluate the capabilities of CT to accurately characterize cystic tumors of the pancreas.

METHOD

Two observers retrospectively evaluated the CT exams of 100 cystic masses of the pancreas, with pathological confirmation. The two observers, blinded about clinical information and the final diagnosis, tried to categorize the lesions according to well established morphologic features. Statistical analysis was performed to measure the agreement between each radiologist and the consensus diagnosis and to evaluate the usefulness of certain CT findings in differentiating one type of cystic pancreatic neoplasm from another.

RESULTS

Serous cystadenoma was better diagnosed by CT [Youden misclassification index (Ymi) = 0.72] than mucinous cystic tumor (Ymi = 0.44) and solid pseudopapillary tumor (cystic variant) (Ymi = 0.47).

CONCLUSION

As patients with previous history of pancreatitis were excluded from the study, CT findings allowed correct characterization of only 60% of cystic pancreatic masses. Among the remaining 40%, 15-20% of the wrong diagnoses could not be corrected by means of CT, given the patterns shown by the tumors. In 20-25% of the cases, a nonspecific diagnosis of cystic mass was made.

CT and US of the pancreas

The diagnostic capabilities of pancreatic imaging continue to improve with technological advancements in computed tomography (CT), ultrasound (US), and magnetic resonance imaging (MRI). To update the practicing radiologist, this article summarizes the current literature on pancreatic imaging, with particular emphasis on CT and US. Pertinent clinical considerations of the disease entities are included, along with illustrative material from the authors' experience.

Serous cystadenoma of the pancreas: report of 30 cases with emphasis on the imaging findings

PURPOSE

Our goal was to evaluate retrospectively 30 cases of serous cystadenoma (SCA) to determine its main imaging features as well as to discuss the differential diagnosis problems versus the other cystic lesions of the pancreas.

METHOD

Thirty SCAs were analyzed; they were all benign lesions, proven at surgery. Twenty-three tumors were evaluated with US, 26 with CT, and 5 with MRI.

RESULTS

Three different morphostructural patterns were identified: microlacunar (n = 19), mixed (n = 6), and macrolacunar (n = 5). The diagnosis of SCA, possible in either the microlacunar or the mixed patterns, was achieved in 74% of cases with US (17/23) and in 61.5% with CT (16/26). Among the 19 patients evaluated with both modalities, the joint information allowed a correct diagnosis in 16 cases (84%). The five macrolacunar tumors were undistinguishable from other cystic masses of the pancreas.

CONCLUSION

The diagnosis of SCA can be considered certain in the microlacunar, likely in the mixed, and not possible in the macrolacunar type.

Solitary cystic tumor of the pancreas: EUS-pathologic correlation

BACKGROUND

It is clinically important to distinguish neoplastic from non-neoplastic pancreatic cysts.

METHODS

Retrospective correlations were made between pathologic and EUS data from 52 pancreatic solitary cystic tumors: mucinous cystadenoma (10), mucinous cystadenocarcinoma (7), serous cystadenoma (5), ductectatic mucinous cystic tumor (10), solid and papillary epithelial neoplasm (5), and non-neoplastic cyst (15). The mean tumor size was 3.5 cm (range, 1.2 cm to 6.0 cm).

RESULTS

Six classifications of the internal structures of these cysts were developed: thick wall type, tumor protruding type, thick septal type, microcystic type, thin septal type, and simple type. Although all neoplastic cysts belonged to the first four types, all non-neoplastic cysts belonged to the last two types. The accuracy of EUS for differentiating tumors was estimated at 96% and 92%, respectively, by two observers.

CONCLUSIONS

EUS may become a mandatory modality for differentiating pancreatic solitary cystic tumors and choosing an optimal treatment.

CT of pancreatic neoplasms. Part II: The unusual tumors

The pancreas gives rise to a remarkable variety of neoplasms other than ductal adenocarcinoma. Although no individual type of tumor in this category is prevalent enough to qualify as common, most types are currently encountered with a frequency far greater than that in decades of the recent past. This change is largely the result of the expanded use of contemporary abdominal imaging. The unusual tumors of the pancreas vary greatly in their biologic behavior and, accordingly, in their clinical consequences and therapeutic requirements. Accurate diagnosis, therefore, can be of considerable clinical relevance. Not only is it worthwhile to distinguish one type of unusual pancreatic tumors from another, it is perhaps of even greater consequence to distinguish the unusual tumors from ordinary pancreatic adenocarcinomas. The goals of this discussion are to expand radiologic awareness of these uncommon but interesting pancreatic neoplasms and to increase familiarity with their diagnostically salient features.

Lymphoepithelial cyst of the pancreas. Report of two cases and review of the literature

CONCLUSION

Lymphoepithelial cyst of the pancreas (LC) is a very rare benign lesion and preoperative diagnosis is difficult. Conservative surgery seems to be the appropriate therapy in symptomatic patients or when a precise preoperative diagnosis is not achieved. The benign behavior of all reported cases suggests that the asymptomatic patients with a certain morphological preoperative diagnosis might be clinically followed up. The histogenesis of LC remains to be elucidated.

BACKGROUND

LC of the pancreas is a cyst that is histologically characterized by a fibrous tissue, a lymphoid component and a lining squamous epithelium.

METHODS

Clinical and pathological findings of two personal cases are reported with review of the literature.

RESULTS

A 56-yr-old man, complaining of epigastric pain, and a 47-yr-old man, with a history of alcohol abuse, were admitted to hospital. In both cases the lesion was detected with abdominal ultrasound but a certain diagnosis was obtained only after histological examination of the resected cysts.

Preoperative cyst fluid analysis is useful for the differential diagnosis of cystic lesions of the pancreas

BACKGROUND/AIMS

It has been suggested that activity of pancreatic enzymes and concentrations of tumoral markers in cyst fluid may help to distinguish pseudocyst, serous, and mucinous cystadenomas. The aim of this study was to prospectively assess the reliability of preoperative biochemical and tumor marker analysis in cyst fluids obtained by fine-needle aspiration for pathological diagnosis.

METHODS

Cyst fluid was obtained preoperatively by fine-needle aspiration, and biochemical and tumoral marker values were measured. The diagnosis of cystic tumors (7 serous cystadenomas and 12 mucinous tumors) was established by surgical specimen analysis. Thirty-one pancreatic pseudocysts complicating well-documented chronic pancreatitis were also studied.

RESULTS

Carbohydrate antigen 19.9 levels of > 50,000 U/mL had a 75% sensitivity and a 90% specificity for distinguishing mucinous tumors from other cystic lesions. Carcinoembryonic antigen levels of < 5 ng/mL had a 100% sensitivity and an 86% specificity for distinguishing serous cystadenomas from other cystic lesions. Amylase levels of > 5000 U/mL had a 94% sensitivity and a 74% specificity for distinguishing pseudocysts from other cystic lesions.

CONCLUSIONS

High carbohydrate antigen 19.9, low carcinoembryonic antigen, and high amylase levels in cyst fluid are very indicative of mucinous tumors, serous cystadenomas, and pseudocysts, respectively.

Dermoid cyst of the head of the pancreas area

We report a case of dermoid cyst of the head of the pancreas area in a 26-yr-old woman radically treated with pancreatoduodenectomy and alive with no recurrence at 6-yr follow-up. The diagnostic and surgical procedures are described, and the literature is reviewed.

Computed tomography and fine-needle aspiration cytology for preoperative evaluation of cystic tumours of the pancreas

Cystic neoplasms of the pancreas are rare. They may present as a mucinous (malignant or potentially malignant) tumour or as benign serous cystadenoma. Accurate preoperative diagnosis is therefore essential, as an asymptomatic serous tumour may safely be followed clinically for years, whereas mucinous tumours require aggressive surgery. Thirteen patients with cystadenoma and cystadenocarcinoma of the pancreas were reviewed and how best to improve the rate of preoperative diagnosis was considered. Fine-needle aspiration cytology and computed tomography enable accurate preoperative distinction between mucinous and serous cystic tumours of the pancreas.

Case report: massive biliary dilatation mimicking cystic retroperitoneal masses on computed tomography

An unusual case is presented in which a massively dilated common bile duct produced a confusing CT image of multiple cystic areas within the abdominal cavity. Cholangiography and CT-cholangiography were useful in establishing the correct diagnosis. The differential diagnosis of cystic retroperitoneal masses is discussed.

Cystic islet cell tumors of the pancreas. A clinico-pathological report of two nonfunctioning cases and review of the literature

Cystic islet cell tumors of the pancreas are extremely rare. The authors report their personal experience with two cases of nonfunctioning cystic endocrine neoplasms. The tumor was diagnosed preoperatively in one case by ultrasonography (US)-guided fine-needle aspiration cytology, while in the other it was identified only in the surgical specimen after a clinical-radiologic diagnosis of pancreatic mucinous cystic tumor. Immunohistochemical assay showed positivity for the generic neuroendocrine markers (neuron specific enolase, or NSE, synaptophysin, and chromogranin A) in both cases and also for glucagon in one case. The neoplasms were resected by distal pancreatectomy with splenectomy and intermediate pancreatectomy respectively. Both patients are alive and recurrence-free 6 mo and 2.5 yr, respectively, after surgery. The authors also review the existing literature, discussing the pathogenesis of such tumors and the imaging techniques and surgical strategies adopted in their management.