Cystic pancreatic lesions,the endless dilemma

Cystic pancreatic lesions involve a wide variety of pathological entities that include neoplastic and non-neoplastic lesions.The proper diagnosis,differentiation,and staging of these cystic lesions are considered a crucial issue in planning further management.There are great challenges for their diagnostic models.In our time,new emerging methods for this diagnosis have been discovered.Endoscopic ultrasonography-guided fine-needle aspiration cytology with chemical and molecular analysis of cyst fluid and EUS-guided fine needlebased confocal laser endomicroscopy,through the needle microforceps biopsy,and single-operator cho-langioscopy/pancreatoscopy are promising methods that have been used in the diagnosis of cystic pancreatic lesions.Hereby we discuss the diagnosis of cystic pancreatic lesions and the benefits of various diagnostic models.

Pancreatic pseudocyst:The past,the present,and the future

A pancreatic pseudocyst is defined as an encapsulated fluid collection with a welldefined inflammatory wall with minimal or no necrosis.The diagnosis cannot be made prior to 4 wk after the onset of pancreatitis.The clinical presentation is often nonspecific,with abdominal pain being the most common symptom.If a diagnosis is suspected,contrast-enhanced computed tomography and/or magnetic resonance imaging are performed to confirm the diagnosis and assess the characteristics of the pseudocyst.Endoscopic ultrasound with cyst fluid analysis can be performed in cases of diagnostic uncertainty.Pseudocyst of the pancreas can lead to complications such as hemorrhage,infection,and rupture.The management of pancreatic pseudocysts depends on the presence of symptoms and the development of complications,such as biliary or gastric outlet obstruction.Management options include endoscopic or surgical drainage.The aim of this review was to summarize the current literature on pancreatic pseudocysts and discuss the evolution of the definitions,diagnosis,and management of this condition.

Recent advances in the diagnostic evaluation of pancreatic cystic lesions

Pancreatic cystic lesions(PCLs)are becoming more prevalent due to more frequent abdominal imaging and the increasing age of the general population.It has become crucial to identify these PCLs and subsequently risk stratify them to guide management.Given the high morbidity associated with pancreatic surgery,only those PCLs at high risk for malignancy should undergo such treatment.However,current diagnostic testing is suboptimal at accurately diagnosing and risk stratifying PCLs.Therefore,research has focused on developing new techniques for differentiating mucinous from non-mucinous PCLs and identifying high risk lesions for malignancy.Cross sectional imaging radiomics can potentially improve the predictive accuracy of primary risk stratification of PCLs at the time of detection to guide invasive testing.While cyst fluid glucose has reemerged as a potential biomarker,cyst fluid molecular markers have improved accuracy for identifying specific types of PCLs.Endoscopic ultrasound guided approaches such as confocal laser endomicroscopy and through the needle microforceps biopsy have shown a good correlation with histopathological findings and are evolving techniques for identifying and risk stratifying PCLs.While most of these recent diagnostics are only practiced at selective tertiary care centers,they hold a promise that management of PCLs will only get better in the future.

Utility of endoscopic ultrasound, cytology and fluid carcinoembryonic antigen and CA 19-9 levels in pancreatic cystic lesions

AIM: To assess the diagnostic accuracy of endoscopic ultrasound (EUS), fluid tumor markers and cytology in distinguishing benign from (pre)malignant pancreatic cystic lesions. METHODS: 46 consecutive patients, referred to a gastroenterologist and surgeon for a symptomatic or incidental pancreatic cyst, were reviewed. EUS, cytology, and carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9) levels were compared with the final diagnosis, based on surgical pathology and/or imaging follow-up of at least 12 mo. Cysts were classified as benign (pseudocyst, serous cystadenoma) or malignant/ pre-malignant (mucinous cystic neoplasm). Receiver- operator characteristics (ROC) curve analysis was performed. RESULTS: The mean age was 56 years; 29% were male and median cyst diameter was 3 cm. Final outcome was obtained in 41 (89%) patients. Twenty-three (56%) of these 41 had surgical pathology. Twenty-three (56%) had benign lesions and 18 (44%) had malignant/pre- malignant lesions. Sensitivity, specificity and positive and negative predictive value of EUS alone to distinguish benign from malignant/premalignant pancreatic cystic lesions were 50%, 56%, 36% and 54% and for cytology were 71%, 96%, 92% and 85%, respectively. The corresponding values for the ROC-derived ideal cutoffswere 75%, 90%, 75%, 90% for CA 19-9 (> 37 U/mL) and 70%, 85%, 79% and 78% for CEA (> 3.1 ng/mL). Subgroup analysis of those with surgical pathology yielded almost identical performance and cutoffs. CONCLUSION: Cytology and cyst fluid tumor marker analysis is a very useful tool in distinguishing benign from (pre)malignant pancreatic cystic lesions.

Incidents and adverse events of endoscopic ultrasoundguided fine-needle aspiration for pancreatic cystic lesions

AIM To evaluate the diagnostic value and safety mainly regarding incidents of endoscopic ultrasound-guided fine-needle aspiration(EUS-FNA) for pancreatic cystic lesions(PCLs).METHODS A total of 150 consecutive patients with suspected PCLs were prospectively enrolled from April 2015 to November 2016. We finally enrolled 140 patients undergoing EUS-FNA. We compared the diagnostic accuracy of EUS-FNA and pathological diagnosis, which is regarded as the gold standard, for PCLs. Patients undergoing EUS-FNA at least 1 wk preoperatively were monitored for incidents and adverse events to evaluate its safety.RESULTS There were 88(62.9%) women and 52(37.1%) men among 140 patients, with a mean age of 50.1(± 15.4) years. There were 67 cysts located in the head/uncinate of the pancreas and 67 in the body/tail, and 6 patients had at least 1 cyst in the pancreas. There were 75 patients undergoing surgery and 55 undergoing EUS-FNA with interval at least 1 wk before other operations, with 3 patients undergoing the procedure twice. The accuracy of EUS-FNA in differentiating benign and malignant lesions was 97.3%(73/75), while the accuracy of characterizing PCL subtype was 84.0%(63/75). The incident rate was 37.9%(22/58), whereas only 1 AE was observed in 58 cases.CONCLUSION EUS-FNA is effective and safe for diagnosis of PCLs, however procedure-related incidents are common. Caution should be taken in patients undergoing EUSFNA.

Needle-based confocal endomicroscopy in the discrimination of mucinous from non-mucinous pancreatic cystic lesions

BACKGROUND Pancreatic cystic lesions(PCLs)are considered a precursor of pancreatic cancer.Needle-based confocal endomicroscopy(nCLE)is an imaging technique that enables visualization of the mucosal layer to a micron resolution.Its application has demonstrated promising results in the distinction of PCLs.This study evaluated the utility of nCLE in patients with indeterminate PCLs undergoing endoscopic ultrasound fine-needle aspiration(EUS-FNA)to distinguish mucinous from non-mucinous lesions.AIM To evaluate the accuracy of nCLE in indeterminate PCLs undergoing EUS-FNA to distinguish mucinous from non-mucinous lesions.METHODS Patients who required EUS-FNA between 2015 and 2017 were enrolled prospectively.During EUS-FNA,confocal imaging,analyses of the tumor markers carcinoembryonic antigen and amylase,and cytologic examination were conducted.All patients were followed for at least 12 mo and underwent laboratory testing and computed tomography scanning or magnetic resonance imaging.nCLE videos were independently reviewed by 6 observers to reach a final diagnosis(mucinous vs non-mucinous)based on criteria derived from previous studies;if there was disagreement>20%,a final diagnosis was discussed after consensus re-evaluation.The sensitivity,specificity,and accuracy of nCLE were calculated.Adverse events were recorded.RESULTS Fifty-nine patients were included in this study.Final diagnoses were derived from surgery in 10 patients,cytology in 13,and imaging and multidisciplinary team review in 36.Three patients were excluded from final diagnosis due to problems with nCLE acquisition.Fifty-six patients were included in the final analysis.The sensitivity,specificity,and accuracy of nCLE were 80%[95%confidence interval(CI):65-90],100%(95%CI:72-100),and 84%(95%CI:72-93),respectively.Postprocedure acute pancreatitis occurred in 5%.CONCLUSION EUS-nCLE performs better than standard EUS-FNA for the diagnosis of indeterminate PCL.

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 echoenhanced 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.

Asymptomatic pancreatic lesions: New insights and clinical implications

Despite great efforts in experimental and clinical research, the prognosis of pancreatic cancer (PC) has not changed significantly for decades. Detection of pre-invasive lesions or early-stage PC with small resectable cancers in asymptomatic individuals remains one of the most promising approaches to substantially improve the overall outcome of PC. Therefore, screening programs have been proposed to identify curable lesions especially in individuals with a familial or genetic predisposition for PC. In this regard, Canto et al recently contributed an important article comparing computed tomography, magnetic resonance imaging, and endoscopic ultrasound for the screening of 216 asymptomatic high-risk individuals (HRI). Pancreatic lesions were detected in 92 of 216 asymptomatic HRI (42.6%). The high diagnostic yield in this study raises several questions that need to be answered of which two will be discussed in detail in this commentary: First: which imaging test should be performed? Second and most importantly: what are we doing with incidentally detected pancreatic lesions? Which ones can be observed and which ones need to be resected?

The Hong Kong consensus recommendations on the diagnosis and management of pancreatic cystic lesions

Background:The finding of pancreatic cystic lesions(PCL)on incidental imaging is becoming increasingly common.International studies report a prevalence of 2.2-44.7%depending on the population,imaging modality and indication for imaging,and the prevalence increases with age.Patients with PCL are at risk of developing pancreatic cancer,a disease with a poor prognosis.This publication summarizes recommendations for the diagnosis and management of PCL and post-operative pancreatic exocrine insufficiency(PEI)from a group of local specialists.Methods:Clinical evidence was consolidated from narrative reviews and consensus statements formulated during two online meetings in March 2022.The expert panel included gastroenterologists,hepatobiliary surgeons,oncologists,radiologists,and endocrinologists.Results:Patients with PCL require careful investigation and follow-up due to the risk of malignant transformation of these lesions.They should undergo clinical investigation and pancreas-specific imaging to classify lesions and understand the risk profile of the patient.Where indicated,patients should undergo pancreatectomy to excise PCL.Following pancreatectomy,patients are at risk of PEI,leading to gastrointestinal dysfunction and malnutrition.Therefore,such patients should be monitored for symptoms of PEI,and promptly treated with pancreatic enzyme replacement therapy(PERT).Patients with poor response to PERT may require increases in dose,addition of a proton pump inhibitor,and/or further investigation,including tests for pancreatic function.Patients are also at risk of new-onset diabetes mellitus after pancreatectomy;they should be screened and treated with insulin if indicated.Conclusions:These statements are an accurate summary of our approach to the diagnosis and management of patients with PCL and will be of assistance to clinicians treating these patients in a similar clinical landscape.

Machine learning in endoscopic ultrasonography and the pancreas:The new frontier?

Pancreatic diseases have a substantial burden on society which is predicted to increase further over the next decades.Endoscopic ultrasonography(EUS)remains the best available diagnostic method to assess the pancreas,however,there remains room for improvement.Artificial intelligence(AI)approaches have been adopted to assess pancreatic diseases for over a decade,but this methodology has recently reached a new era with the innovative machine learning algorithms which can process,recognize,and label endosonographic images.Our review provides a targeted summary of AI in EUS for pancreatic diseases.Included studies cover a wide spectrum of pancreatic diseases from pancreatic cystic lesions to pancreatic masses and diagnosis of pancreatic cancer,chronic pancreatitis,and autoimmune pancreatitis.For these,AI models seemed highly successful,although the results should be evaluated carefully as the tasks,datasets and models were greatly heterogenous.In addition to use in diagnostics,AI was also tested as a procedural real-time assistant for EUS-guided biopsy as well as recognition of standard pancreatic stations and labeling anatomical landmarks during routine examination.Studies thus far have suggested that the adoption of AI in pancreatic EUS is highly promising and further opportunities should be explored in the field.