Publications by authors named "Masayoshi Tadehara"

Background And Aim: No prospective studies have verified the incidence of cholecystitis in patients using the covered self-expandable metallic stent. In this study, we aimed to investigate the incidence of cholecystitis and its risk factors after low axial force covered self-expandable metallic stent placement for malignant distal biliary obstruction.

Methods: This multicenter prospective study included patients diagnosed with unresectable distal biliary obstruction between November 2019 and October 2022 who underwent low axial force covered self-expandable metallic stent placement.

View Article and Find Full Text PDF

Objectives: Recently, artificial intelligence (AI) has been applied to clinical diagnosis. Although AI has already been developed for gastrointestinal (GI) tract endoscopy, few studies have applied AI to endoscopic ultrasound (EUS) images. In this study, we used a computer-assisted diagnosis (CAD) system with deep learning analysis of EUS images (EUS-CAD) and assessed its ability to differentiate GI stromal tumors (GISTs) from other mesenchymal tumors and their risk classification performance.

View Article and Find Full Text PDF
Article Synopsis
  • - The study aimed to validate the use of endoscopic ultrasound-guided tissue acquisition (EUS-TA) combined with stereomicroscopic on-site evaluation (SOSE) as a diagnostic tool for identifying resectable pancreatic cancer (R-PC) and borderline resectable pancreatic cancer (BR-PC).
  • - A total of 78 patients undergoing EUS-TA were analyzed, with a focus on achieving a specific sensitivity based on a stereomicroscopic measurement called the white core cutoff value; results showed a high sensitivity of 90.4% for diagnosing malignancies.
  • - The study concluded that EUS-TA with SOSE is a reliable method for diagnosing malignant lesions, demonstrating high overall sensitivity (90.8%), specificity
View Article and Find Full Text PDF

REV7 is a multifunctional protein implicated in various biological processes, including DNA damage response. REV7 expression in human cancer cells affects their sensitivity to DNA-damaging agents. In the present study, we investigated the significance of REV7 in pancreatic ductal adenocarcinoma (PDAC).

View Article and Find Full Text PDF

Objective: The concept of BRCAness has been proposed as a homologous recombination repair dysfunction triggered by a genetic defect in the BRCA pathway including the BRCA1/2 mutations. A certain number of pancreatic ductal adenocarcinoma (PDAC) patients have BRCAness. However, a large-scale analysis of BRCAness in PDAC has not been performed.

View Article and Find Full Text PDF
Article Synopsis
  • A new method called Automated Multiband Imaging System (AMUS) was tested for estimating the necessary tissue amount in biopsy samples from patients with subepithelial lesions (SELs).
  • The study involved 20 patients and showed that the whitish core amounts calculated by AMUS correlated well with the manually measured sizes and the samples' suitability for pathology.
  • AMUS proved to be an accurate and simpler alternative to the more complex Sample Isolation Processing by Stereomicroscopy (SIPS) for ensuring proper tissue sampling.
View Article and Find Full Text PDF

Objectives: We evaluated the usefulness of a newly developed system with which the total amount of whitish cores in endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) samples is automatically calculated (automated multiband imaging system [AMUS]).

Methods: From 30 prospectively enrolled patients suspected of having pancreatic cancer, four EUS-FNAB specimens per patient were obtained. Following AMUS calculations, two specimens were prepared after stereomicroscopy-guided manual division into whitish and reddish sections (isolation group), and the other two were prepared without such division (no-isolation group).

View Article and Find Full Text PDF

CD109 is a glycosylphosphatidylinositol-anchored glycoprotein, whose expression is upregulated in some types of malignant tumors. High levels of CD109 in tumor cells have been reported to correlate with poor prognosis; however, significance of CD109 stromal expression in human malignancy has not been elucidated. In this study, we investigated the tumorigenic properties of CD109 in pancreatic ductal adenocarcinoma (PDAC).

View Article and Find Full Text PDF
Article Synopsis
  • A 76-year-old man with a month-long history of epigastric pain was diagnosed with pancreatic neuroendocrine carcinoma (PanNEC) after imaging revealed a mass in the pancreatic head and liver nodules, along with signs of jaundice and hepatic dysfunction.
  • Initial treatments included platinum-based chemotherapy and streptozotocin, but the patient showed progressive disease, leading to the addition of pembrolizumab, specifically targeting his high microsatellite instability (MSI-high) status.
  • Despite a temporary improvement in his condition, the patient ultimately experienced disease progression and passed away 1 year and 7 months after diagnosis, highlighting the need to routinely check MSI status in PanNEC cases for better treatment responses.
View Article and Find Full Text PDF
Article Synopsis
  • - The study investigates whether fine-needle biopsy (FNB) needles provide better specimen quality and tissue collection than fine-needle aspiration (FNA) needles during endoscopic ultrasound-guided tissue acquisition for subepithelial lesions (SELs).
  • - In a retrospective analysis involving 56 SEL cases, the FNB group showed a significantly higher median adequacy score for histopathological specimens compared to the FNA group, with both methods achieving a 100% technical success rate.
  • - Ultimately, FNB needles are more effective at collecting core tissue and enhancing specimen quality, but the diagnostic accuracy remains similar for both FNB and FNA when paired with sample isolation processing techniques.
View Article and Find Full Text PDF

Background: Endoscopic retrograde cholangiopancreatography (ERCP) is associated with complications such as post-ERCP pancreatitis (PEP). Protease inhibitors, including nafamostat mesylate (NM), have been evaluated for prophylaxis against PEP.

Aim: We describe the first multicenter randomized controlled trial assessing the prophylactic efficacy of NM against PEP.

View Article and Find Full Text PDF

We herein report the first case of metastatic pancreatic leiomyosarcoma derived from the urinary bladder diagnosed by an endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) in a 65-year-old woman. The patient had undergone total cystectomy for bladder leiomyosarcoma. Four years thereafter, a nodule was observed in her left lung on chest computed tomography.

View Article and Find Full Text PDF

A schwannoma is a tumor originating from Schwann cells. It is occasionally observed in the abdominal viscera in the form of a submucosal tumor derived from the gastric or duodenal muscularis propria. To date, only a few studies have reported on pancreatic schwannomas.

View Article and Find Full Text PDF

Objectives: The aim of this study is to estimate the cutoff length for stereomicroscopically visible white core (SVWC) required for the pathological diagnosis of subepithelial lesions (SELs) from samples obtained using a novel 22-G Franseen biopsy needle and determine the sensitivity using the SVWC cutoff length.

Patients And Methods: Thirty patients with SELs requiring pathological diagnoses were included. EUS-guided fine-needle biopsies (EUS-FNBs) were performed using a novel 22G Franseen biopsy needle.

View Article and Find Full Text PDF

Background: Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) is new onset acute pancreatitis after ERCP. This complication is sometimes fatal. As such, PEP should be diagnosed early so that therapeutic interventions can be carried out.

View Article and Find Full Text PDF

Background: Balloon dilation (BD) is a simple, effective procedure for postoperative benign bilioenteric strictures (BBESs). Factors associated with BBES recurrence after endoscopic BD have not been studied adequately. This study examined the outcomes and 1-year recurrence factors in patients with BBES who underwent endoscopic BD.

View Article and Find Full Text PDF

Background/objectives: Stent-induced pancreatic duct stricture (SI-PDS) is a complication associated with pancreatic stent placement. However, symptomatic SI-PDS associated with prophylactic pancreatic duct stents has not been sufficiently investigated.

Methods: We examined the incidence and characteristics of symptomatic SI-PDS in patients who underwent pancreatic duct stent placement to prevent post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) between April 2007 and March 2017.

View Article and Find Full Text PDF

Background/objectives: A breakthrough in chemotherapy for pancreatic ductal adenocarcinoma (PDAC) may be achieved using precision medicine, which involves identifying cases that are highly likely to respond to a certain treatment and then performing that treatment. BRCAness has been receiving attention as a novel predictor of anticancer drug sensitivity in PDAC, making the screening of BRCAness paramount.

Methods: We conducted the first-ever examination of the feasibility of analyzing BRCAness using multiplex ligation-dependent probe amplification (MLPA).

View Article and Find Full Text PDF

Background: Biliary cannulation failure is a major problem during endoscopic retrograde cholangiopancreatography. It remains unclear how duodenal papilla morphology affects biliary cannulation. Therefore, we proposed a new classification system for the duodenal papilla based on oral protrusion pattern (ratio of the length of the oral protrusion to the transverse diameter of the papilla) and papilla pattern.

View Article and Find Full Text PDF

Pancreatic granular cell tumors (GCTs) are rare and making an imaging diagnosis of pancreatic GCT is difficult because it has no definite characteristics on contrast-enhanced computed tomography (CE-CT) or magnetic resonance imaging (MRI) owing to varying findings. We report about a 32-year-old woman who presented with an incidental finding of a pancreatic tumor with a past history of excision of a right forearm GCT nodule 12 years ago. CE-CT revealed a 23-mm-sized homogeneous low enhancement tumor in the arterial phase in the pancreatic body.

View Article and Find Full Text PDF

Background: Endoscopic transmural drainage is performed for symptomatic peripancreatic fluid collections (PPFCs). Long-term transmural double-pigtail stent (DPS) placement is useful in preventing recurrences. There are few reports on the long-term safety of DPS placement.

View Article and Find Full Text PDF