Norihisa Kimura

Background: Endoscopic treatment of postoperative biliary strictures in patients with surgically altered anatomy can be technically challenging. The Drill Dilator advances by rotational torque with minimal forward pushing, potentially facilitating dilation while maintaining endoscope stability. This study evaluated the feasibility and safety of the Drill Dilator as an initial dilation device for postoperative biliary strictures in patients with surgically altered anatomy. Methods: We retrospectively reviewed 46 endoscopic sessions for postoperative biliary strictures performed between December 2016 and April 2026. Among these, 18 initial treatment sessions were included in the comparative analysis. Six sessions in which the Drill Dilator was used as the initial dilation device were evaluated and compared with 12 sessions using conventional dilation devices. Results: The Drill Dilator successfully passed and dilated the stricture in all sessions (100%). Additional dilation with another device was required in 50% of sessions (3/6). Technical success was achieved in all sessions (100%). Mild post-ERCP cholangitis (PEC) occurred in two patients (33.3%), with no severe procedure-related adverse events. In the conventional dilation group, device passage and technical success rates were 100% (12/12) and 91.7% (11/12), respectively. Conclusions: The Drill Dilator was feasible as an initial dilation device for postoperative biliary strictures in patients with surgically altered anatomy. Its use may facilitate subsequent endoscopic dilation, particularly in situations where alignment between the dilation device and the bile duct is challenging.

Background: The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for distal cholangiocarcinoma (dCCA) uses depth of invasion (DOI) for T classification; however, it does not consider invasion into adjacent organs such as the pancreas. We investigated the prognostic significance of DOI and pancreatic invasion in patients with dCCA. Methods: We retrospectively analyzed 130 patients with dCCA who underwent pancreatoduodenectomy between 2003 and 2016. The optimal DOI cutoff for predicting overall survival (OS) was determined using time‐dependent receiver operating characteristic analysis. Associations between clinicopathological factors, pancreatic invasion, and prognosis were evaluated using Kaplan–Meier survival analysis and Cox proportional hazards models. Results: The optimal DOI cutoff for OS was 4 mm. Patients with DOI > 4 mm had significantly poorer survival than those with DOI ≤ 4 mm ( p < 0.0001). Pancreatic invasion was associated with worse prognosis ( p < 0.001) and was more prevalent in tumors with greater DOI. Among patients with DOI > 4 mm, pancreatic invasion significantly worsened OS ( p < 0.05), whereas no prognostic impact was observed in patients with DOI ≤ 4 mm. Multivariate analysis identified the combination of DOI > 4 mm and pancreatic invasion, lymph node metastasis, histological type, and positive resection margin as independent adverse prognostic factors. A novel classification incorporating DOI, pancreatic invasion, and lymph node status provided improved prognostic stratification. Conclusion: The combination of DOI > 4 mm and pancreatic invasion is an independent predictor of poor prognosis in dCCA. Incorporating pancreatic invasion into DOI‐based classification may improve prognostic assessment beyond the current AJCC staging system.

Background: Despite advancements in pancreatic surgery, new-onset diabetes mellitus following pancreatectomy (NODMP), persists, affecting patients’ quality of life. Predicting NODMP before surgery could significantly enhance postoperative care. Methods: This study included 220 patients who underwent pancreatoduodenectomy or distal pancreatectomy at Hirosaki University Hospital between January 2008 and December 2020. Patients with preoperative diabetes or 5.7%, remP/S ratio 3. Multivariate analysis confirmed that a remP/S ratio 5.7% were independent predictors of NODMP. The risk scoring system indicated that patients with both risk factors have a fivefold higher risk of developing NODMP within 2 years compared with those without either risk factor. Conclusions: Preoperative remP/S ratio and HbA1c were significant predictors of NODMP, enabling the effective stratification of NODMP risk and facilitating the early treatment of the disease.

Pancreatic stellate cells (PSCs) are the origin of cancer-associated fibroblasts. Type 2 diabetes mellitus (T2D) may promote pancreatic ductal adenocarcinoma (PDAC), eliciting changes in the quiescent PSC (qPSC) population from the precancerous stage. However, the details are unknown. We evaluated the subpopulations of qPSCs and the impact of T2D. PSCs isolated from 8-week-old C57BL/6J mice and diabetic db/db mice were analyzed by single-cell RNA-seq. Sorted qPSCs and PDAC cells were transplanted into allogenic mice. The isolated qPSCs were broadly classified into mesothelial cell and pancreatic fibroblast (Paf) populations by single-cell RNA-seq. Pafs were subclassified into inflammatory Pafs, myofibroblastic Pafs (myPafs) and a small population named tumor immunity- and angiogenesis-promoting Pafs (tapPafs), expressing Cxcl13 . In the subcutaneous transplantation model, the tumors transplanted with myPafs were significantly larger than the tumors transplanted with tapPafs. An increase in myPafs and a decrease in tapPafs were observed from the precancerous stage in human T2D, indicating the effects of tumor progression. This study revealed the subpopulation changes in qPSCs in T2D. A therapy that increases the number of tapPafs could be a therapeutic option for patients with PDAC and T2D and even those in a precancerous stage of T2D.

Lymphatic fluid drains from the liver via the periportal lymphatic, hepatic venous lymphatic, and superficial lymphatic systems. We performed a postmortem study to clarify the three-dimensional structure and flow dynamics of the human hepatic venous lymphatic system, as it still remains unclear. Livers were excised whole from three human cadavers, injected with India ink, and sliced into 1-cm sections from which veins were harvested. The distribution of lymphatic vessels was observed in 5 μm sections immunostained for lymphatic and vascular markers (podoplanin and CD31, respectively) using light microscopy. Continuity and density of lymphatic vessel distribution were assessed in en-face whole-mount preparations of veins using stereomicroscopy. The structure of the external hepatic vein wall was assessed with scanning electron microscopy (SEM). The lymphatic dynamics study suggested that lymphatic fluid flows through an extravascular pathway around the central and sublobular veins. A lymphatic vessel network originates in the wall of sublobular veins, with a diameter greater than 110 μm, and the peripheral portions of hepatic veins and continues to the inferior vena cava. The density distribution of lymphatic vessels is smallest in the peripheral portion of the hepatic vein (0.03%) and increases to the proximal portion (0.22%, p = 0.012) and the main trunk (1.01%, p < 0.001), correlating positively with increasing hepatic vein diameter (Rs = 0.67, p < 0.001). We revealed the three-dimensional structure of the human hepatic venous lymphatic system. The results could improve the understanding of lymphatic physiology and liver pathology.

Background: Emphysematous pancreatitis is acute pancreatitis associated with emphysema based on imaging studies and has been considered a subtype of necrotizing pancreatitis. Although some recent studies have reported the successful use of conservative treatment, it is still considered a serious condition. Computed tomography (CT) scan is useful in identifying emphysema associated with acute pancreatitis; however, whether the presence of emphysema correlates with the severity of pancreatitis remains controversial. In this study, we managed two cases of severe acute pancreatitis complicated with retroperitoneal emphysema successfully by treatment with lavage and drainage. Case presentation: Case 1: A 76-year-old man was referred to our hospital after being diagnosed with acute pancreatitis. At post-admission, his abdominal symptoms worsened, and a repeat CT scan revealed increased retroperitoneal gas. Due to the high risk for gastrointestinal tract perforation, emergent laparotomy was performed. Fat necrosis was observed on the anterior surface of the pancreas, and a diagnosis of acute necrotizing pancreatitis with retroperitoneal emphysema was made. Thus, retroperitoneal drainage was performed. Case 2: A 50-year-old woman developed anaphylactic shock during the induction of general anesthesia for lumbar spine surgery, and peritoneal irritation symptoms and hypotension occurred on the same day. Contrast-enhanced CT scan showed necrotic changes in the pancreatic body and emphysema surrounding the pancreas. Therefore, she was diagnosed with acute necrotizing pancreatitis with retroperitoneal emphysema, and retroperitoneal cavity lavage and drainage were performed. In the second case, the intraperitoneal abscess occurred postoperatively, requiring time for drainage treatment. Both patients showed no significant postoperative course problems and were discharged on postoperative days 18 and 108, respectively. Conclusion: Acute pancreatitis with emphysema from the acute phase highly indicates severe necrotizing pancreatitis. Surgical drainage should be chosen without hesitation in necrotizing pancreatitis with emphysema from early onset.

Background: The differential diagnosis between gallbladder cancer (GBC) and xanthogranulomatous cholecystitis (XGC) remains quite challenging, and can possibly lead to improper surgery. This study aimed to distinguish between XGC and GBC by combining computed tomography (CT) images and deep learning (DL) to maximize the therapeutic success of surgery.Methods: We collected a dataset, including preoperative CT images, from 28 cases of GBC and 21 XGC patients undergoing surgery at our facility. It was subdivided into training and validation (n = 40), and test (n = 9) datasets. We built a CT patch‐based discriminating model using a residual convolutional neural network and employed 5‐fold cross‐validation. The discriminating performance of the model was analyzed in the test dataset.Results: Of the 40 patients in the training dataset, GBC and XGC were observed in 21 (52.5%), and 19 (47.5%) patients, respectively. A total of 61 126 patches were extracted from the 40 patients. In the validation dataset, the average sensitivity, specificity, and accuracy were 98.8%, 98.0%, and 98.5%, respectively. Furthermore, the area under the receiver operating characteristic curve (AUC) was 0.9985. In the test dataset, which included 11 738 patches, the discriminating accuracy for GBC patients after neoadjuvant chemotherapy (NAC) (n = 3) was insufficient (61.8%). However, the discriminating model demonstrated high accuracy (98.2%) and AUC (0.9893) for cases other than those receiving NAC.Conclusion: Our CT‐based DL model exhibited high discriminating performance in patients with GBC and XGC. Our study proposes a novel concept for selecting the appropriate procedure and avoiding unnecessary invasive measures.

症例は60歳，女性．広範囲門脈浸潤を伴う局所進行切除可能境界膵癌であったが門脈再建困難とされ，gemcitabine+nab-paclitaxel療法12コースおよびgemcitabine療法23コースが施行された．治療開始後，早期に腫瘍マーカーは正常化し，原発巣の著明な縮小が認められた．以後，原発巣は不明瞭化し，腫瘍マーカーは正常範囲内を長期間維持したため，根治手術として亜全胃温存膵頭十二指腸切除術を施行した．病理組織像は広範囲に線維化が認められ，腫瘍細胞は認められず，病理学的完全奏効と判定された．術後，S-1単剤による補助化学療法を6カ月間施行し，術後8カ月経過し無再発生存中である．