Diagnostic and therapeutic strategies in pancreatic adenosquamous carcinoma: Molecular and clinical insights in managing metastatic disease.

Adenosquamous carcinoma of the pancreas (ASCP) is a rare and aggressive variant of pancreatic cancer, characterized by both adenocarcinoma and squamous cell carcinoma components. It presents significant diagnostic and therapeutic challenges due to its atypical histology and poor prognosis. A 72-year-old male presented with abdominal pain, lighter-colored stools, and intermittent nausea. Initial imaging revealed a complex mass in the distal pancreatic body and tail. Elevated lipase levels and subsequent endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) suggested an atypical pancreatic lesion with keratinizing squamous cells. Further investigation through fiberoptic bronchoscopy and EBUS-guided transbronchial needle aspiration (TBNA) confirmed carcinoma with squamous differentiation. Genetic testing identified KRAS G12D and PIK3CA mutations. The multidisciplinary tumor board recommended systemic chemotherapy with mFOLFIRINOX and G-CSF support. The patient underwent twelve cycles of mFOLFIRINOX with dose adjustments for thrombocytopenia and effective management of chemotherapy-related side effects. Restaging CT scans showed a decrease in tumor size and stable metastatic nodes. The patient showed a partial biochemical response with decreasing CA 19-9 levels and disease stabilization on imaging. This case demonstrates the critical role of a multidisciplinary approach in managing rare pancreatic malignancies. ASCP requires a comprehensive diagnostic and therapeutic strategy involving advanced imaging, histopathological confirmation, and personalized chemotherapy. Integrating advanced diagnostic techniques, molecular profiling, and a multidisciplinary approach is essential for improving patient outcomes and providing comprehensive care for this challenging malignancy. Addressing the psychological aspects and offering compassionate care are vital for supporting patients through their treatment journey.

Comparing the diagnostic adequacy of 25-Gauge fork-tip versus franseen versus reverse-bevel-type needles in EUS-guided tissue acquisition: A prospective randomized study with a retrospective control.

Background and Objectives: EUS-guided fine-needle biopsy (FNB) is an established technique for the acquisition of tissue to diagnose lesions of the gastrointestinal tract and surrounding organs. Recently, newer-generation FNB needles have been introduced, including a second-generation reverse-bevel and the third-generation fork-tip and Franseen needles. We aimed to determine if there was any difference between these needles in terms of cytopathological diagnostic yield, sample cellularity, or sample bloodiness. Methods: One hundred twenty-seven consecutive patients undergoing EUS-guided FNB of any solid lesion were randomized to use either a Franseen or fork-tip needle in a 1:1 ratio and were compared with 60 consecutive historical cases performed with reverse-bevel needles. Patient and procedure characteristics were recorded. Cases were reviewed by a blinded cytopathologist and graded based on cellularity and bloodiness. Overall diagnostic yield was calculated for each study arm. Results: One hundred seventy-six cases were eligible for analysis, including 109 pancreatic masses, 24 lymphoid lesions, 17 subepithelial lesions, and 26 other lesions. The final diagnosis was malignancy in 127 cases (72%). EUS-guided FNB was diagnostic in 141 cases (80%) overall and in 89% of cases where malignancy was the final diagnosis. There was no difference in diagnostic yield, sample cellularity, or sample bloodiness between the different needle types. There was no difference in adverse events between groups. Conclusions: EUS-guided FNB performed using 25-gauge Franseen, fork-tip, and reverse-bevel needles resulted in similar diagnostic yield, sample cellularity, and sample bloodiness. Our results may not be extrapolated to larger-caliber needles of the same design.

A Humanized Patient-Derived Xenograft Model for Pancreatic Cancer.

Pancreatic cancer is associated with a high mortality rate, and there are still very few effective treatment options. Patient-derived xenografts have proven to be invaluable preclinical disease models to study cancer biology and facilitate testing of novel therapeutics. However, the severely immune-deficient mice used to generate standard models lack any functional immune system, thereby limiting their utility as a tool to investigate the tumor-immune cell interface. This chapter will outline a method for establishment of "humanized" patient-derived xenografts, which are reconstituted with human immune cells to imitate the immune-rich microenvironment of pancreatic cancer.

Echoendoscopic ultrasound pancreatic adenocarcinoma diagnosis and theranostic approach: should KRAS mutation research be recommended in everyday practice?

Background: The impact of KRAS mutation testing on pancreatic ductal adenocarcinoma (PDAC) samples by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for reducing the need to repeat EUS-FNA has been demonstrated. Such testing however is not part of standard practice for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB). Objectives: We aim to analyse the proportion of non-contributive samples by EUS-FNB and to evaluate the impact of KRAS mutation testing on the diagnosis, theranostics and survival. Design: In this retrospective study, the impact on diagnosis and survival of KRAS testing for contributive and non-contributive samples by EUS-FNB was analysed. Methods: The EUS-FNB samples, combined with KRAS testing using the Idylla® technique on liquid-based cytology from patients with PDAC between February 2019 and May 2023, were retrospectively reviewed. The cytology results were classified according to the guidelines of the World Health Organization System for Reporting Pancreaticobiliary Cytopathology (WHOSRPC). Results: A total of 85 EUS-FNB specimens were reviewed. In all, 25 EUS-FNB samples did not lead to a formal diagnosis of PDAC according to the WHOSRPC (30.2%). Out of these 25, 11 (44%) could have been considered positive for a PDAC diagnosis thanks to the KRAS mutation test without carrying out further diagnosis procedures. The sensitivity of KRAS mutation testing using the Idylla technique was 98.6%. According to the available data, survival rates were not statistically different depending on the type of mutation. Conclusion: KRAS mutation testing on liquid-based cytology using the Idylla or equivalent technique, combined with the PDAC EUS-FNB sample, should become a standard for diagnosis to avoid delaying treatment by doing another biopsy. Furthermore, knowledge of the KRAS status from treatment initiation could be used to isolate mutations requiring targeted treatments or inclusion in clinical research trials, especially for wild-type KRAS PDAC.

Diagnostic and theranostic interest of searching for a KRAS mutation in echoendoscopic ultrasound biopsies of pancreatic adenocarcinomas The echoendoscopic ultrasound diagnostic of pancreatic adenocarcinomas sometimes remains difficult due to the nature of these tumors with a particular microenvironment. For more than 30 years, several authors have underlined the importance of searching for a KRAS mutation on samples taken by echoendoscopic ultrasound to improve diagnostic performance. However, this research is not common practice. Our retrospective study made it possible to review the files of 85 patients with pancreatic adenocarcinoma in whom an echoendoscopic ultrasound biopsy was performed with a search for the KRAS mutation (with second-generation fine needle biopsy). Forty-four percent could have been considered positive for the diagnosis of PDAC thanks to the search for the KRAS mutation without repeating new samples. Furthermore, knowledge of the KRAS mutation type from diagnosis would make it possible to isolate mutations justifying possible targeted treatments.

K-ras gene mutation analysis to diagnosis pancreatic adenocarcinoma from endoscopic ultrasound-guided tissue acquisition; a systematic review and meta-analysis.

BACKGROUND: Endoscopic ultrasound-guided tissue acquisition (EUS-TA) has high sensitivity for the pathological diagnosis of pancreatic masses, but also a high false-negative rate. K-ras gene mutations occur in over 75 % of pancreatic ductal adenocarcinomas (PDAC), and this meta-analysis evaluated the utility of detecting K-ras gene mutations from EUS-TA specimens for the diagnosis of PDAC. METHODS: Relevant studies in PubMed, the Cochrane Library, and Web of Science were systematically searched. Meta-analysis was performed on data from the selected studies using a bivariate model to provide pooled values of sensitivity, specificity, and their 95 % confidence intervals (CIs). RESULTS: This meta-analysis included 1521 patients (from 10 eligible studies) who underwent EUS-TA with K-ras gene mutation analysis for diagnosis of pancreatic solid masses. The pooled estimates of sensitivity and specificity were 76.6 % (95 % CI, 70.9-81.5 %) and 97.0 % (95 % CI, 94.0-98.5 %), respectively, for pathological diagnosis, 75.9 % (95 % CI 69.5-81.4 %) and 95.3 % (95 % CI, 92.3-97.2 %) for K-ras gene mutation analysis, and 88.7 % (95 % CI 87.1-91.7 %) and 94.9 % (95 % CI, 91.5-97.0 %) for pathological diagnosis in combination with K-ras gene mutation analysis. The sensitivity for diagnosis of PDAC was significantly higher for pathological diagnosis in combination with K-ras gene mutation analysis than for pathological diagnosis or K-ras gene mutation analysis alone (both, p < 0.001). There was no difference in specificity between pathological diagnosis in combination with K-ras gene mutation analysis and both either (p = 0.234, 0.945, respectively). CONCLUSIONS: K-ras gene mutation analysis in combination with to pathological diagnosis of EUS-TA increases the accuracy of differential diagnosis of PDAC.

Dry suction versus wet suction technique of endoscopic ultrasound-guided fine-needle biopsy for diagnosis of solid pancreatic lesions: study protocol of a multicenter randomized controlled non-inferiority trial.

BACKGROUND: Studies have shown that the wet suction technique in endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) generates better histological diagnostic accuracy and specimen quality than the dry suction technique. However, conclusions of wet suction on the diagnostic accuracy of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) are still controversial. Besides, the optimal number of passes for EUS-FNB has not been determined. We aimed to design a large multicenter randomized trial to compare the diagnostic accuracy of dry suction versus wet suction technique in solid pancreatic lesions (SPLs) using 22G Franseen needles and determine the optimal number of passes required for EUS-FNB. METHODS: This is a multi-center open-label, randomized controlled non-inferiority trial with two parallel groups. Two hundred patients with SPLs will undergo EUS-FNB using 22G Franseen needles in 4 tertiary hospitals in China and will be randomly assigned to the dry suction group and wet suction group in a ratio of 1:1. The primary endpoint is diagnostic accuracy. Secondary endpoints include the optimal number of needle passes, sensitivity, specificity, specimen quality, cytological diagnoses, time of the procedure, and incidence of complications. DISCUSSION: This study has been designed to determine (i) whether EUS-FNB using 22G Franseen needle with dry suction is non-inferior to wet suction in terms of diagnostic accuracy and (ii) the optimal number of passes during EUS-FNB of SPLs using 22G Franseen needle. TRIAL REGISTRATION: ClinicalTrials.gov NCT05549856. Registered on September 22, 2022.

Pancreatic Neuroendocrine Tumor (Pan-NET) Presented by Abdominal Pain: A Case Report and Literature Review.

A pancreatic neuroendocrine tumor (Pan-NET) is a rare neoplasm originating in the neuroendocrine system. Carcinoid syndrome occurs in approximately 19% of patients with functional Pan-NETs, typically when liver metastases occur. In this paper, we describe the case of a patient with a low-grade non-functional Pan-NET, but with a typical clinical presentation of carcinoid syndrome. An 81-year-old male was admitted to our Department of Internal Medicine at Cannizzaro Hospital (Catania, Italy) because of the onset of abdominal pain with nausea, loose stools, and episodic flushing. Firstly, an abdominal contrast-enhanced CT scan showed a small pancreatic hyper-vascular mass; then, a gallium-68 DOTATOC integrated PET/CT revealed an elevated expression of SSTR receptors. Serum chromogranin A and urinary 5-HIAA measurements were negative. We performed an endoscopic ultrasonography (EUS) by a fine-needle biopsy (EUS-FNB), allowing the immunostaining of a small mass (0.8 cm) and the diagnosis of a low-grade (G1) non-functional Pan-NET (NF-Pan-NET). Surgery was waived, while a follow-up strategy was chosen. The early recognition of Pan-NETs, although rare, is necessary to improve the patient's survival. Although helpful to allow for immunostaining, EUS-FNB needs to be warranted in future studies comparing EUS-FNB to EUS-FNA (fine-needle aspiration), which is, to date, reported as the tool of choice to diagnose Pan-NETs.

Safety and Diagnostic Yield of Endoscopic Ultrasound-Guided Fine-Needle Biopsy for Hypervascular Pancreatic Lesions.

Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is a common technique for diagnosing pancreatic lesions with high accuracy and a low incidence of procedural adverse events. However, occasional adverse events, particularly bleeding, may occur. Procedures for hypervascular lesions are considered important, but their risks are unknown. We aimed to evaluate the safety and diagnostic yield of EUS-FNB for hypervascular pancreatic solid lesions. This study included 301 patients with 308 solid pancreatic lesions who underwent EUS-FNB between May 2011 and December 2018. We performed propensity-score matching to balance clinical differences between hypervascular and hypovascular lesions and analyzed 52 lesions. We compared the safety and diagnostic performance of propensity score-matched cohorts. The sensitivity, specificity, and accuracy rates of EUS-FNB for hypervascular lesions were 94.7%, 100%, and 96.2%, and those for hypovascular lesions were 80.0%, 100%, and 84.6%, respectively. There was no difference in diagnostic performance between hypervascular and hypovascular lesions. Furthermore, adverse events occurred in only one patient (pancreatitis) in the hypovascular group. There were no significant differences in the occurrence of adverse events between hypervascular and hypovascular lesions (0% vs. 3.8%, p = 1.000). Therefore, EUS-FNB may be safe with a high diagnostic yield, even for hypervascular solid pancreatic lesions.

Validation of a Novel EUS-FNB-Derived Organoid Co-Culture System for Drug Screening in Patients with Pancreatic Cancer.

Cancer-associated fibroblasts (CAFs) have been shown to impact the chemosensitivity of patient-derived tumor organoids (PDTOs). However, the published literature comparing PDTO response to clinical outcome does not include CAFs in the models. Here, a co-culture model was created using PDTOs and CAFs derived from endoscopic ultrasound-guided fine-needle biopsies (EUS-FNBs) for potential use in drug screening applications. Co-cultures were established, and growth was compared to monocultures using image metrics and a commercially available assay. We were able to establish and expand validated malignant PDTOs from 19.2% of adenocarcinomas from EUS-FNBs. CAFs could be established from 25% of the samples. The viability of PDTOs in the mixed cell co-culture could be isolated using image metrics. The addition of CAFs promoted PDTO growth in half of the established co-cultures. These results show that co-cultures can be established from tiny amounts of tissue provided by EUS-FNB. An increased growth of PDTOs was shown in co-cultures, suggesting that the present setup successfully models CAF-PDTO interaction. Furthermore, we demonstrated that standard validation techniques may be insufficient to detect contamination with normal cells in PDTO cultures established from primary tumor core biopsies.

Diagnostic Yield of Repeat Endoscopic Ultrasound-Guided Fine Needle Biopsy for Solid Pancreatic Lesions.

PATIENTS AND METHODS: we performed a retrospective case-control study, including cases with repeat EUS FNB for a solid pancreatic lesion, matched on a 1:2 ratio on age, sex, tumor location and presence of chronic pancreatitis with cases diagnosed on the first EUS FNB. RESULTS: thirty-four cases and 68 controls were included in the analysis. Diagnostic accuracies were 80% and 88% in the repeat and single EUS FNB groups, respectively (p = 0.824). The second EUS FNB had a sensitivity of 80%, a specificity of 75%, a positive predictive value of 96%, and a negative predictive value of 33%. Of the 34 patients in the repeat EUS FNB group, 25 (74%) had a positive diagnosis with the second EUS FNB, 4 (12%) after surgery due to a second negative EUS FNB, 4 (12%) during clinical follow-up, and 1 (3%) after a third EUS FNB. Of the 25 patients diagnosed on the repeat EUS FNB, 17 (68%) had pancreatic adenocarcinomas, 2 (8%) neuroendocrine tumors, 2 (8%) other autoimmune pancreatitis, 2 (8%) chronic pancreatitis nodules, 1 (4%) renal cancer metastasis, and 1 (4%) other malignant diagnostic. There were no complications reported after the second EUS FNB in this study. CONCLUSION: repeat EUS FNB made a diagnosis in three fourths of patients with solid pancreatic lesions and a first negative EUS FNB, with 26% of benign lesions. This supports the repetition of EUS FNB sampling in this clinical situation.

Advances in the Early Diagnosis of Pancreatic Ductal Adenocarcinoma and Premalignant Pancreatic Lesions.

Pancreatic cancer is one of the most lethal human malignancies, in part because it is often diagnosed at late stages when surgery and systemic therapies are either unfeasible or ineffective. Therefore, diagnosing pancreatic cancer in earlier stages is important for effective treatment. However, because the signs and symptoms may be nonspecific and not apparent until the disease is at a late stage, the timely diagnoses of pancreatic cancer can be difficult to achieve. Recent studies have shown that selective screening and increased usage of biomarkers could improve the early diagnosis of pancreatic cancer. In this review, we discuss recent advancements in the early detection of pancreatic ductal carcinoma and precancerous lesions. These include innovations in imaging modalities, the diagnostic utility of various biomarkers, biopsy techniques, and population-based surveillance approaches. Additionally, we discuss how machine learning methods are being applied to develop integrated methods of identifying individuals at high risk of developing pancreatic disease. In the future, the overall survival of pancreatic cancer patients could be improved by the development and adoption of these new methods and techniques.

Endoscopic Ultrasound-Guided Fine-Needle Biopsies to Generate Preclinical Disease Models to Study Inflammation in Pancreatic Ductal Adenocarcinoma.

Patient-derived xenografts (PDXs) are valuable models to study cancer biology, behavior, and response to therapies in vivo. Pancreatic cancer is an aggressive and treatment-resistant disease, and typical biopsies are often of low cellular yield and therefore present challenges for the creation of PDXs. This chapter will describe a method to establish PDX models from tissue biopsies obtained via endoscopic ultrasound-guided fine-needle aspiration, a relatively noninvasive technique which compared to surgery is available to pancreatic cancer patients at all stages of disease. Furthermore, we also describe methods to incorporate "humanization" of PDXs via reconstitution with human immune cells, thus mimicking the immune cell-rich microenvironment of pancreatic tumors.

Endoscopic ultrasound-guided tissue acquisition with or without rapid on-site evaluation for solid pancreatic lesions: five years of experience from a single center.

BACKGROUND: Endoscopic ultrasound (EUS)-guided tissue acquisition (TA) by EUS-guided fine needle aspiration (FNA) or fine needle biopsy (FNB) is a standard diagnostic procedure for solid pancreatic lesions. Whether rapid on-site evaluation (ROSE) should be used to support EUS-TA remains controversial. Here we assessed the diagnostic performance of EUS-TA with or without self-ROSE for solid pancreatic masses. METHODS: Three hundred and seventy EUS-TA cases with self-ROSE and 244 cases without ROSE were retrospectively enrolled between August 2018 and June 2022. All procedures including ROSE were performed by the attending endoscopist. Clinical data, EUS characteristics, and diagnostic performance for distinguishing benign from malignant solid pancreatic masses including accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were compared between groups. RESULTS: Self-ROSE improved the diagnostic accuracy of solid pancreatic lesions by 16.7% in the EUS-TA group (p < 0.001) and by 18.9% in the EUS-FNA alone group (p < 0.001). Self-ROSE also improved the diagnostic sensitivity by 18.6% in the EUS-TA group (p < 0.001) and by 21.2% in the EUS-FNA alone group (p < 0.001). Improvements in the diagnostic accuracy by self-ROSE in the EUS-FNB group were not significant. 2.2 ± 0.7, 2.4 ± 0.9, 2.3 ± 0.7, 2.5 ± 0.9, 2.1 ± 0.6, and 2.1 ± 0.7 needle passes were required in the EUS-TA, EUS-FNA, and EUS-FNB with or without self-ROSE groups, respectively. CONCLUSIONS: Self-ROSE significantly improved the accuracy and sensitivity of EUS-FNA alone and EUS-TA diagnosis of solid pancreatic lesions and helped to reduce needle passes during the procedure. Whether self-ROSE benefits EUS-FNB and whether EUS-FNB alone is comparable to EUS-FNA with self-ROSE require further clarification.

Usefulness of cytological diagnosis in pancreatic endoscopic ultrasound-guided fine needle aspiration or biopsy: Comparison with histological diagnosis and relationship with puncture route and sample acquisition method.

BACKGROUND: The purpose of this study was to clarify the role of cytology when using endoscopic ultrasound-guided fine needle aspiration or biopsy (EUS-FNA/FNB) for pancreatic lesions by comparison with histology, and also to examine differences in diagnostic accuracy depending on the puncture route and sample acquisition method. METHODS: We studied 146 cases in which cytology and histology were performed when undertaking pancreatic EUS-FNA/FNB and the final histological diagnosis was obtained from surgically resected samples. Cytological, histological, and combined diagnoses with cytology and histology (combined diagnosis) detected malignant including suspected malignancy, indeterminate, and benign lesions. RESULTS: The accuracy of both cytology and histology in pancreatic EUS-FNA/FNB was 80.1%, with the combined diagnosis having an improved accuracy of 88.4%. The accuracy obtained with cytology was 80.0% for trans-duodenal puncture samples and 80.3% for trans-gastric puncture samples, with no difference between them. By contrast, the accuracy obtained with histology was 76.5% for trans-duodenal samples and 85.2% for trans-gastric samples, and they differed depending on the puncture route. The cytology accuracy was 80.9% for FNA and 79.8% for FNB, while the histology accuracy was 72.3% for FNA and 83.8% for FNB. CONCLUSIONS: Combining cytological diagnosis with histological diagnosis improved the diagnostic accuracy of EUS-FNA/FNB. Compared with histological diagnosis, cytological diagnosis showed stable diagnostic accuracy without being affected by differences in the puncture route or sample acquisition method.

Fluorescence confocal microscopy for rapid evaluation of EUS fine-needle biopsy in pancreatic solid lesions.

Video 1EUS fine-needle biopsy of a pancreatic solid lesion evaluated with fluorescence confocal microscopy.

New digital confocal laser microscopy may boost real-time evaluation of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) from solid pancreatic lesions: Data from an international multicenter study.

BACKGROUND: Pancreatic cancer is an aggressive malignancy and a leading cause of cancer death worldwide; its lethality is partly linked to the difficulty of early diagnosis. Modern devices for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) were recently developed to improve targeting and sampling of small lesions, but innovative technologies for microscopic assessment are still lacking. Ex vivo fluorescence confocal laser microscopy (FCM) is a new digital tool for real-time microscopic assessment of fresh unfixed biological specimens, avoiding conventional histological slide preparation and potentially being highly appealing for EUS-FNB specimens. METHODS: This study evaluated the possible role of FCM for immediate evaluation of pancreatic specimens from EUS-FNB. It involved comparison of the interobserver agreement between the new method and standard histological analysis during international multicenter sharing of digital images. Digital images from 25 cases of EUS-FNB obtained with real-time FCM technology and 25 paired digital whole-slide images from permanent conventional paraffin sections were observed by 10 pathologists from different Institutions in Europe, Japan, and the United States, in a blinded manner. The study evaluated 500 observations regarding adequacy, morphological clues, diagnostic categories, and final diagnosis. FINDINGS: Statistical analysis showed substantial equivalence in the interobserver agreement among pathologists using the two techniques. There was also good inter-test agreement in determining sample adequacy and when assigning a diagnostic category. Among morphological features, nuclear enlargement was the most reproducible clue, with very good inter-test agreement. INTERPRETATION: Findings in this study are from international multicenter digital sharing and are published here for the first time. Considering the advantages of FCM digital diagnostics in terms of reduced time and unaltered sample maintenance, the ex vivo confocal laser microscopy may effectively improve traditional EUS-FNB diagnostics, with significant implications for planning modern diagnostic workflow for pancreatic tumors. FUNDING: This study was not supported by any funding source.

EUS-guided biopsy of an intraventricular mass in a patient with ventricular tachycardia.

Video 1Endoscopic ultrasound-guided fine-needle biopsy of an intraventricular mass in a patient with ventricular tachycardia.

Standardized Methods Using EUS-guided Fine-needle Biopsy and a Minimal Medium Creates Three Pancreatic Cancer Organoids.

BACKGROUND/AIM: Recently, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) has been conducted for diagnosing pancreatic ductal adenocarcinoma (PDAC), after which obtained samples were used in organoid cultures. However, no standardized method for PDAC organoid cultures exists. Therefore, to standardize or simplify sample collection and culture methods for PDAC organoids, we performed a floating culture using non-minced specimens obtained by EUS-FNB in a minimal medium, lacking growth factors or inhibitors for pancreatic organoids. PATIENTS AND METHODS: A total of 38 patients with clinically diagnosed PDAC were enrolled in the study. First, EUS-FNB was conducted using a 22- or 25-gauge biopsy needle. Then, a surplus of samples was collected for organoid formation after rapid on-site cytological evaluations of sample adequacy. Subsequently, the established organoids were compared with clinical data and pathological diagnosis, following periodic observations and evaluations for morphology. RESULTS: PDAC organoids were successfully created in 24 of the 38 cases (63.2%), including four cases with pathologically inconclusive EUS-FNB results. Afterward, PDAC organoid morphology was classified into ductal, dormant, and adhesive small cluster (ASC) types. Although the ductal and ASC types were seen separately, they were also seen together in other cases, which we named "mixed type". CONCLUSION: We propose a feasible and straightforward method for establishing organoids, especially for diagnosing PDAC, particularly when the result of EUS-FNB is pathologically inconclusive. Furthermore, PDAC organoids are morphologically classified into three types reported for the first time.

Accuracy and clinical outcomes of pancreatic EUS-guided fine-needle biopsy in a consecutive series of 852 specimens.

Background and Objectives: Pancreatic EUS-guided fine needle biopsy (EUS-FNB) is increasingly used. Accuracy of EUS-FNB, particularly for benign diseases, utility of additional EUS-FNB if malignancy is suspected but initial diagnosis is inconclusive, and complication rate are not fully elucidated. We evaluated operating characteristics of EUS-FNB overall and for different diagnostic categories, value of additional EUS-FNB if malignancy is suspected but initial diagnosis is inconclusive, and frequency and type of complications. Methods: A retrospective tertiary single-center study including 852 consecutive pancreatic SharkCore EUS-FNBs from 723 patients between 2015 and 2020. EUS-FNB diagnoses were applied according to Papanicolaou Society's system and each category was further subcategorized. Results: Sufficient tissue cylinders for a histologic diagnosis were obtained in 93.4% (796/852). Accuracy was overall, for malignant, and benign entities 85.6% (confidence interval [CI]: 83.2%-87.9%), 88.3% (CI: 85.9%-90.4%), and 94% (CI: 92.2%-95.5%). Sensitivity and accuracy of EUS-FNB for autoimmune pancreatitis (AIP) (n = 15) was 83.3% (CI: 58.6%-96.4%) and 99.2% (CI: 98.3%-99.7%). Of patients in whom malignancy was suspected but initial EUS-FNB diagnosis was inconclusive, 7.3% (53/723) underwent one or two additional EUS-FNBs, and in 54.7% (29/53) of these, a malignant diagnosis was established. The frequency of hospitalization following EUS-FNB was 4.7%, with 0.2% (n = 2) incidents needing active intervention. Conclusions: We found a high accuracy of pancreatic EUS-FNB across all diagnostic categories including rare entities, such as AIP. In patients with a clinical suspicion of malignancy, additional EUS-FNB resulted in a conclusive diagnosis in more than half of cases. Complications necessitate hospitalization in almost 5%, but the majority are self-limiting.

The Diagnosis of Small Gastrointestinal Subepithelial Lesions by Endoscopic Ultrasound-Guided Fine Needle Aspiration and Biopsy.

Endoscopic ultrasonography (EUS) has been widely accepted in the diagnosis of all types of tumors, especially pancreatic tumors, lymph nodes, and subepithelial lesions (SELs). One reason is that the examination can provide a detailed observation, with tissue samples being immediately obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). Many SELs are detected incidentally during endoscopic examinations without symptoms. Most SELs are mesenchymal tumors originating from the fourth layer, such as gastrointestinal stromal tumors (GISTs), leiomyomas, and schwannomas. GISTs are potentially malignant. Surgical treatment is recommended for localized GISTs of ≥20 mm. However, the indications for the diagnosis and follow-up of GISTs of <20 mm in size are controversial. There are several reports on the rapid progression or metastasis of small GISTs. Therefore, it is important to determine whether a SEL is a GIST or not. The main diagnostic method is EUS-FNA. Recently, endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) using a new biopsy needle has been reported to obtain larger tissue samples. Additionally, various biopsy methods have been reported to have a high diagnostic rate for small GISTs. In local gastric SELs, regardless of the tumor size, EUS can be performed first; then, EUS-FNA/B or various biopsy methods can be used to obtain tissue samples for decision-making in relation to therapy and the follow-up period.