Yuichi Suzuki

Purpose: NRG1 fusions drive oncogenic HER2/HER3 signaling and define a rare, clinically actionable subset of pancreatic cancer (PC). Zenocutuzumab, a bispecific HER2/HER3-targeting antibody, has shown antitumor activity in NRG1 fusion–positive PC. However, real-world detection of NRG1 fusions may vary according to assay design, target coverage, and the incorporation of RNA sequencing. Materials and Methods: We evaluated the observed frequencies and clinicogenomic features of reported NRG1 fusions across the Japanese national Comprehensive genomic profiling (CGP) database and international public CGP data sets spanning five CGP platforms (total N = 12,647). We additionally describe an illustrative PC case in which an NRG1 fusion was confirmed only after RNA-based reanalysis. Results: NRG1 fusions were identified in 7 of 12,647 cases (0.055%; 0%–0.339% across platforms), and most were KRAS wild-type (6/7). The index case, a 41-year-old man with invasive adenocarcinoma associated with intraductal tubulopapillary neoplasm, showed no definitive pathogenic alterations on the initial CGP report. Targeted reanalysis prompted by an 8p copy-number abnormality identified an in-frame APP::NRG1 fusion by RNA sequencing, which was subsequently confirmed by fusion-specific reverse-transcription polymerase chain reaction. Conclusion: NRG1 fusions in PC are rare yet clinically actionable. RNA-inclusive workflows should be considered in selected cases, particularly those without a canonical KRAS alteration.

Background/Objectives: The role of peroral pancreatoscopy (POPS) in patients with main-duct and mixed-type intraductal papillary mucinous neoplasm (MD/mixed-IPMN) remains unclear. This retrospective multicenter case series aimed to evaluate the feasibility and safety of POPS using the 9-Fr eyeMAX and to describe additional intraductal findings, potential surgical impact, and biopsy–surgery concordance. Methods: Consecutive patients with MD/mixed-IPMN in whom POPS was attempted between May 2023 and September 2025 were retrospectively analyzed. Pre-POPS imaging findings, POPS findings, procedural outcomes, adverse events, surgical outcomes, and concordance between POPS-guided biopsy and surgical pathology were evaluated. Results: Among the 20 patients, 14 were men, and the median age was 74.5 years (range, 46–83 years). IPMNs were classified as main-duct type in five patients (25%) and mixed type in 15 (75%). On endoscopic ultrasonography, mural nodules were identified in 14 patients (70%), with a median diameter of 11 mm (range, 3–25 mm). Endoscopic papillary intervention was performed in 6 patients (30%). The technical success rate of POPS insertion was 95% (19/20). Mural nodules were detected by POPS in 17 patients (85%), and biopsy under POPS guidance was performed a median of 5 times (range, 1–10). The adequate tissue sampling rate was 86% (88/102). Mild post-ERCP pancreatitis occurred in 1 patient (5%). Twelve patients (60%) underwent surgery. The concordance rate between POPS-targeted biopsy and surgical pathology was 45% (5/11); however, R0 resection was achieved in 11 patients (92%). Conclusions: In this small retrospective case series, POPS using the 9-Fr eyeMAX was feasible and provided additional intraductal information in selected patients. However, its diagnostic role remains adjunctive because POPS-guided biopsy showed limited reliability.

Background/Objectives: Transabdominal ultrasonography (TUS) is widely used for the detection of gallbladder lesions (GBLs), but differentiating malignant lesions from non-malignant lesions remains challenging. Microvascular flow imaging (MVFI), including superb microvascular imaging, detective flow imaging, and B-flow, enables visualization of low-flow vessels without contrast agents. This study aimed to characterize MVFI vascular features of GBLs and evaluate their reproducibility. Methods: We retrospectively analyzed 42 patients with GBLs who underwent TUS between March 2022 and December 2025. Two blinded readers independently assessed B-mode and MVFI findings. The evaluated MVFI findings included vascular flow detection, number of basal vessels, vessel shape, vessel thickness, and vessel irregularity. Interobserver agreement was assessed using Cohen’s kappa coefficient, and imaging findings were compared between invasive malignant and non-malignant lesions. Results: Of the 42 lesions, 10 were invasive malignant and 32 were non-malignant. Vascular signals were detected in all invasive malignant lesions and in 21 of 32 non-malignant lesions. Multiple basal vessels and vessel dilation were more frequently observed in invasive malignant lesions. Interobserver agreement was excellent for the number of basal vessels (κ = 0.91) and good for vessel thickness (κ = 0.72), indicating that these findings were more reproducible than other MVFI features. Conclusions: MVFI enables visualization of intralesional vascular features in GBLs. Multiple basal vessels and vessel dilation were associated with invasive malignancy and showed favorable reproducibility. These findings may serve as candidate imaging markers for future prospective validation.

Biliary drainage after hepaticojejunostomy can be challenging, particularly when recurrent tumor results in isolation of segmental intrahepatic bile ducts. Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) has been increasingly used as an alternative drainage approach in such patients.[1] [2] However, the antegrade deployment of multiple stents through endosonographically created routes (ESCRs) has not been standardized.[3] [4] [5] A 60-year-old man who had undergone right hepatectomy with hepaticojejunostomy for bile duct cancer was admitted with cholangitis due to a hepaticojejunostomy stricture ([Fig. 1]). EUS-HGS was initially performed via B2, and a 7-Fr dedicated plastic stent was placed. Because cholangitis subsequently developed in the isolated B3, an additional EUS-HGS was performed; however, recurrent cholangitis persisted. Biopsy from the B2 ESCR revealed adenocarcinoma, confirming local recurrence ([Fig. 2]). To control refractory cholangitis and allow systemic chemotherapy, antegrade partial stent-in-stent deployment via dual ESCRs was attempted ([Fig. 3]). First, a landmark guidewire was advanced alongside the B2 plastic stent into the jejunal limb and left in place. After reinsertion of the duodenoscope, a guidewire was placed alongside the B3 plastic stent. An 8-mm, 8-cm uncovered self-expandable metal stent (Niti-S Large Cell SR Slim Delivery, Taewoong Medical, Seoul, Korea) was deployed in an antegrade manner from B3 to the jejunal limb. A 7-Fr plastic stent (Through & Pass Type IT, Gadelius Medical, Tokyo, Japan) was placed in the B3 ESCR. The guidewire was then introduced through the B2 ESCR alongside the landmark guidewire and advanced through a mesh cell of the first metal stent. A second identical uncovered metal stent was then deployed in a partial stent-in-stent fashion. Finally, a 7-Fr plastic stent was left in the B2 ESCR ([Fig. 4], [Video 1]). Transient fever resolved conservatively, and systemic chemotherapy was initiated. Video 1 Antegrade partial stent-in-stent deployment is performed through dual ESCRs for disconnected B2 and B3 ducts after right hepatectomy with hepaticojejunostomy. To the best of our knowledge, this is the first report of antegrade partial stent-in-stent deployment through dual ESCRs for disconnected B2 and B3 ducts after right hepatectomy with hepaticojejunostomy. Endoscopy_UCTN_Code_TTT_1AS_2AH Received: 05 May 2026 Accepted after revision: 26 May 2026 Article published online: 12 June 2026 © 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/). Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

A 79‐year‐old man presented with fever and jaundice. Laboratory tests revealed elevated inflammatory markers and hepatobiliary enzymes. Magnetic resonance imaging revealed a 20 × 16 cm giant hepatic cyst compressing the intrahepatic bile ducts. Emergency endoscopic retrograde cholangiopancreatography revealed intrahepatic bile duct dilatation secondary to cystic compression. An endoscopic nasobiliary drainage tube was inserted. After the cholangitis improved, the tube was replaced with a plastic stent. The patient was discharged but was readmitted 11 days later with recurrent fever and loss of appetite. Computed tomography revealed thickening of the cyst wall and internal debris, consistent with an infected hepatic cyst. Given the patient's poor general condition and presence of compressed vessels and bile ducts along the percutaneous puncture route, endoscopic ultrasound‐guided cyst drainage (EUS‐CD) with nasocystic drainage was performed. After clinical improvement, surgical fenestration was attempted but aborted due to inflammation and friability with bleeding around the endosonographically/EUS‐guided created route (ESCR). On day 25 after EUS‐CD, conversion to internal trans‐ESCR drainage was performed using a 7‐Fr, 15‐cm double‐pigtail stent, and the transpapillary stent was removed because bile duct compression had resolved. The infection recurred 22 days later owing to stent occlusion, requiring stent exchange and additional drainage via ESCR. Finally, three plastic stents were placed, and the patient had no further infection recurrence. After infection control with nasocystic drainage using EUS‐CD, multiple stent placements via ESCR can provide safe, effective, and durable treatment for giant infected hepatic cysts that are unsuitable for percutaneous drainage or surgery.

Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) using a 22-gauge needle and a 0.018-inch guidewire is well suited for bile duct puncture and initial guidewire insertion [1] [2]; however, subsequent tract dilation and stent delivery remain technically challenging. Although dilation devices compatible with a 0.018-inch guidewire have been reported [3] [4], tract dilation carries a potential risk of bile leakage. Furthermore, because no catheter specifically designed for a 0.018-inch guidewire has been available, switching to a stiff guidewire generally requires multiple device exchanges. This additional step may prolong the procedure and increase the risk of bile leakage [5]. A novel uneven double-lumen cannula (UDLC; PIOLAX, Tokyo, Japan) features an ultra-tapered tip designed for a 0.018-inch guidewire and a side lumen for a 0.035-inch guidewire, with a maximum diameter of 6-Fr ([Fig. 1]). This design enables effective bile aspiration while allowing one-step insertion of an additional stiff guidewire without device exchange, thereby improving procedural safety and stability while minimizing tract dilation. In the present case of EUS-HGS performed in a patient with hilar biliary obstruction and previously placed fully covered multi-hole metallic stents ([Fig. 2] and [Fig. 3]), a 0.018-inch guidewire (J-wire Premier Non-marker, J-Mit Co., Ltd, Kyoto, Japan) could not be advanced across the stents. Because of the short insertion length, a 0.018-inch guidewire alone was insufficient to provide adequate stability for stent delivery. Consequently, the novel UDLC was inserted over the 0.018-inch guidewire, enabling bile aspiration followed by insertion of an additional 0.035-inch stiff guidewire. Finally, a dedicated plastic stent (7-Fr, 10 cm, Through & Pass Type IT, Gadelius Medical, Tokyo, Japan) was successfully deployed without additional tract dilation ([Fig. 4]; [Video 1]). To the best of our knowledge, this is the first report of EUS-HGS using the novel UDLC designed for a 0.018-inch guidewire. This device addresses the limitation associated with 22-gauge needle access during EUS-HGS. Endoscopy_UCTN_Code_TTT_1AR_2AZ Endoscopy_UCTN_Code_CCL_1AZ_2AC Article published online: 13 February 2026 © 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/). Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

Selective biliary cannulation during balloon enteroscopy-assisted endoscopic retrograde cholangiopancreatography (BE-ERCP) after total gastrectomy can be extremely challenging, particularly when the papilla is located in an anatomically unusual position [1]. Placing a traction-band clip (SureClip Traction Band, Micro-Tech, Nanjing, China) can stabilize the papilla and facilitate successful cannulation [2] [3]; however, this technique has not been reported during BE-ERCP. Herein, we describe a case in which traction-band clip deployment enabled the successful biliary cannulation for a papilla located in the horizontal limb after total gastrectomy ([Fig. 1], [Video 1]). A 78-year-old man who underwent total gastrectomy with Roux-en-Y reconstruction was referred for evaluation of an extrahepatic bile duct tumor. On the computed tomographic image, enhanced tumor was shown in the common bile duct ([Fig. 2]); therefore, BE-ERCP was planned. When the single-balloon enteroscope (SIF-H290S; Olympus Medical Systems, Tokyo, Japan) was inserted, the papilla was located in the horizontal limb. Despite using a rotatable papillotome, selective biliary cannulation was extremely difficult because of its marked mobility. Therefore, traction-band clip-assisted cannulation was attempted. A SureClip Traction Band was deployed on the anal side of the papilla. The second SureClip was rotated to engage the band, and the enteroscope was gently withdrawn. The clip was then applied to the duodenal wall. Finally, a third clip was deployed to provide stronger counter-traction. After deployment of the traction-band system, the papilla became sufficiently stabilized. A flexible guidewire (Fielder Flex; Asahi Intech, Aichi, Japan) was advanced into the main pancreatic duct. Using the double-guidewire technique, selective biliary cannulation was finally achieved. Biopsy of the bile duct tumor with a sheath device revealed adenocarcinoma ([Fig. 3] and [Fig. 4]). To the best of our knowledge, this is the first report of selective biliary cannulation using a traction-band clip during BE-ERCP after total gastrectomy. This novel technique may facilitate biliary cannulation in cases where the papilla is located in the horizontal limb. Endoscopy_UCTN_Code_TTT_1AR_2AB Article published online: 03 February 2026 © 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/). Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany