Clostridioides difficile infection (CDI) remains a leading cause of healthcare-associated diarrhea worldwide, with high morbidity, recurrence, and healthcare burden. Timely and accurate diagnosis, effective treatment, and preventive strategies are critical in improving patient outcomes. This review presents a comprehensive overview of CDI and focuses on diagnostic criteria, severity classifications, recurrence risk prediction, and therapeutic approaches, emphasizing both international and Japanese perspectives. The use of the Bristol Stool Scale and appropriate stool testing protocols helps ensure diagnostic accuracy and avoid overtreatment. Japan's adoption of the MN severity criteria, which incorporate clinical, laboratory, and imaging findings, contrasts with laboratory-based classifications in international guidelines. While both structured diagnostic algorithms and evidence-based treatment guidelines offer prognostic value, MN criteria may better reflect real-world clinical decision-making in Japan. CDI recurrence remains a significant clinical challenge. This review highlights two predictive models-CHIEF score and the novel Days of Antibiotic Spectrum Coverage (DASC) metric-developed in Japanese cohorts. Both tools enable early identification of high-risk patients and support decisions on prophylactic or tailored therapy. Therapeutic options include fidaxomicin (FDX), vancomycin, and metronidazole (MTZ). Recent international guidelines favor FDX due to its superior microbiota-sparing properties and reduced recurrence rates. However, MTZ remains an option for mild cases in Japan because of cost considerations and differences in CDI strain prevalence. By comparing local and global practices, this review underscores the importance of region-specific data in optimizing CDI management and encourages further integration of emerging risk stratification tools and treatment strategies to improve care across diverse clinical settings.

Background: Zonular apparatus capsular bag (ZACB) insufficiency causes late postoperative spontaneous in-the-bag intraocular lens (IOL) dislocation, a serious complication of cataract surgery. Spontaneous posterior capsule rupture (SPCR) with IOL dislocation is a rare complication. This study reports and discusses clinical features and outcomes of ZACB insufficiency with SPCR. Methods: We retrospectively reviewed 7 cases of SPCR that developed after cataract surgery at Nippon Medical School Musashi Kosugi Hospital between March 2021 and February 2025. Clinical records and surgical videos were examined to collect data on patient age, sex, associated systemic and ocular conditions, medications, dates of IOL implantation and explantation, signs and symptoms prompting explantation, and surgical outcomes. The stage of capsular rupture and location of intraocular lens dislocation were classified on the basis of intraoperative findings. Results: The anterior capsule rim and zonule were intact in 5 SPCR cases, with the exchanged IOL fixated in the sulcus. Two cases of SPCR exhibited both anterior and posterior capsule dislocation requiring intrascleral IOL fixation. The average age of the patients was 52 years (range: 29-83 years; 6 men, 1 woman), and 5 (4 men, 1 woman) had atopic dermatitis. Time since the initial cataract surgery ranged from 10 to 20 years (mean, 13.8 years). Conclusions: Most SPCR cases were associated with atopic dermatitis, with minor trauma possibly contributing to ZACB insufficiency. Capsule morphology was preserved in most SPCR cases, with the exception of posterior capsule rupture.

Background: The incidence of diabetic gangrene is increasing because patients are living longer with diabetes. Methods: Data from 27 Japanese adults with diabetic foot gangrene were analyzed. All affected sites, including bones, were surgically excised. Amputation was performed at the toe or metatarsal bones, and bone marrow was adequately exposed. This retrospective review investigated the results of this therapy. Results: Healing was satisfactory for 26 of the 27 (96.3%) patients. Recurrence was noted in 4 (14.8%) of the 27 patients, the median number of operations was 1 (range, 1-3), and 1 (3.7%) patient required reconstructive surgery. White blood cell (WBC) count and C-reactive protein (CRP) level were significantly higher in recurrent cases than in non-recurrent cases (p = 0.009 and p = 0.001, respectively; Wilcoxon rank sum test). The cutoff values for WBC count and CRP level were 17,300/μL (specificity 100%; sensitivity 75%) and 10.23 mg/dL (specificity 81.8%; sensitivity 100%), respectively, using the Youden index. WBC count and CRP level also significantly positively associated with the number of operations (p = 0.018 and p = 0.018, respectively; Jonckheere-Terpstra trend test). Conclusions: A higher WBC count and CRP level may predict recurrence and number of operations. Therapy using bone marrow exposure is simple and useful for diabetic foot gangrene. Thus, minor amputation with bone marrow exposure may be an effective treatment for diabetic foot gangrene.

Background: Public engagement in medical education, including the participation of simulated patients, has a favorable influence on students. In Objective Structured Clinical Examinations (OSCE) scenarios, the psychological and social aspects in the biopsychosocial model of the patient do not seem to have been adequately considered. The objective of this study was to identify a series of strategies to explore the concerns of the general public and reflect these concerns in the background characteristics of simulated patients. To enhance understanding, we will also discuss specific examples from studies. Methods: This study used qualitative document analysis of newspaper articles submitted by the general public. We searched for frequently occurring words in 1,127 articles, and 455 frequent words were selected as potential targets for this study. In this pilot study, the word "caregiving" was selected for analysis, and 43 articles containing this word were included in the database. Extracted texts were qualitatively analyzed using steps for coding and theorizing to generate emergent themes. Results: A storyline was obtained to establish the simulated patient background for the OSCE. We were able to integrate patient background, such as, "a company employee who regrets not being able to provide the care he had envisioned while balancing work and caregiving." Conclusions: The background of simulated patients in medical education can be formulated through document analysis of newspaper articles. Future studies should attempt to verify the validity of this strategy.

Background: Cancer patients of working age often face multiple social challenges that remain unrecognized and unmet. The current study aimed to examine the adequacy of social support and unexpressed support needs for social problems among working-age cancer patients in Japan. Methods: A web-based cross-sectional survey was conducted among 683 cancer patients aged 20-64 years. Using the Social Problem Checklist for Working-age Cancer Patients, we assessed the severity of social problems, the sources of support consulted, and the adequacy of support received. We analyzed differences in the adequacy of support by source and identified social problems associated with unexpressed and unmet support needs using dot diagrams. Results: Although many participants experienced severe social problems, a substantial proportion reported either not perceiving a need for support or not expressing their support needs. Unexpressed needs were most common in domains related to loneliness, intimate relationships, and sexuality. Adequate support was more frequently reported when non-family sources were consulted, particularly when patients accessed both family and non-family support. Patients who relied solely on family reported support adequacy levels that were similar to those who consulted no one. Conclusions: Many working-age cancer patients in Japan experience significant social distress but do not voice their support needs, particularly regarding sensitive topics. Support from non-family sources plays a key role in addressing unmet and unexpressed needs. These findings highlight the importance of multidisciplinary psychosocial care and proactive efforts to identify hidden distress and diversify support networks for working-age cancer patients.

Background: The accuracy and safety of sentinel lymph node (SLN) dissection (SLND) have not been established for women with invasive breast cancer (BC) who underwent neoadjuvant chemotherapy (NAC). The purpose of this study was to identify factors that predict pathologically negative axillary lymph node (ALN) status and recurrence-free survival (RFS) in women with invasive BC and clinically negative ALN after NAC followed by SLND. Methods: The analysis included patients with BC (T1-4, N0-1, M0) treated with NAC who had clinically negative ALNs after NAC followed by SLND between January 2018 and May 2022. Age, clinical tumor size, clinical ALN status, estrogen receptor (ER), progesterone receptor, human epidermal growth factor receptor 2 (HER2), molecular subtype, histological grade, Ki67, all at baseline, and pathologic tumor size after NAC were analyzed for correlations with pathological ALN metastasis and RFS. Results: SLND identified at least one SLN (blue or radioactive node) in all of 112 consecutive patients. Multivariable analysis showed that age >50 years, clinically negative ALN, histologic grade II or III, ER negativity, triple negative subtype (all at baseline), and pathologically invasive tumor size of ≤2.0 cm after NAC showed a significant correlation with pathologically negative ALN. HER2 positivity and pathological complete response of the primary tumor were significantly correlated with favorable RFS. Conclusions: These predictors of pathologically negative ALN and RFS after NAC are useful for planning appropriate surgical and adjuvant treatment for BC patients.

Background: Laparoscopic hepatectomy (Lap-H) is increasingly being performed in Japan, but the high cost and handling complexity of laparoscopic ultrasonographic (US) probes remain a barrier to its wider adoption. Intraoperative ultrasonography is essential for safe liver resection; however, specialized laparoscopic probes are expensive, have a limited field of view, and are difficult to manipulate. Methods: To overcome these limitations, we developed a practical technique using an open-surgery-type microconvex US probe in Lap-H. The probe is inserted via an umbilical incision using a Lap Protector mini™ and EZ Access™, and probe manipulation is achieved through a cord-based control system. We applied this method in over 150 Lap-H cases before the introduction of a dedicated laparoscopic US system. Results: This technique enabled the acquisition of axial and sagittal images with a wide and deep field of view, enhancing anatomical orientation and lesion visualization. There were no complications such as air leaks or equipment failure. The method allowed for the use of contrast-enhanced ultrasound and minimized interference with the operative field. Conclusions: The use of open-surgery-type US probes in Lap-H offers a cost-effective, safe, and practical alternative to expensive laparoscopic US systems. This innovation may lower the barrier for institutions initiating Lap-H programs and promote the broader adoption of high-quality intraoperative ultrasonography in minimally invasive liver surgery.

Background: Sentinel lymph node biopsy (SLNB) is the standard procedure for axillary staging in early breast cancer. Although the radioisotope (RI) method is highly accurate, it requires nuclear medicine facilities and exposes patients to radiation. Superparamagnetic iron oxide (SPIO) tracers were shown to be noninferior to RI in trials outside Japan but are not approved in Japan. Resovist (ferucarbotran), an MRI contrast agent containing SPIO, may be an alternative. This study compared the feasibility and diagnostic performance of Resovist-based magnetic SLNB with the RI method. Methods: This paired study analyzed 27 breast cancer cases treated with both RI-based and Resovist-based magnetic SLNB. Resovist 0.8 mL was injected subcutaneously above the tumor or into the periareolar region, and the site was gently massaged. The injection-site skin and subcutaneous tissue were excised to prevent pigmentation. Identification rates were assessed at the patient and node levels, and subgroup analysis of patients stratified by body mass index (BMI <25 vs. ≥25) was performed. McNemar's and Fisher's exact tests were used. Results: SLN identification was 100% (27/27 patients) for RI and 88.9% (24/27) for the magnetic method. Among 49 nodes, the results were RI+/Mag+ for 34, RI+/Mag− for 6, and RI−/Mag+ for 9, yielding detection rates of 81.6% (RI) and 87.8% (magnetic). No allergic reactions, pigmentation, or injection site complications occurred. BMI had no significant effect (p > 0.05). Conclusions: Resovist-based magnetic SLNB was feasible and safe, and had detection rates comparable to those of RI. Optimization of injection conditions may further improve accuracy.

Background: Epithelial ovarian cancer (EOC) is increasingly affecting women of reproductive age. Fertility-sparing surgery (FSS) is an option for patients with early EOC who want to preserve their fertility, but the oncologic safety of FSS requires rigorous evaluation. This study retrospectively compared the oncologic outcomes of FSS with those of radical surgery (non-FSS) for patients with FIGO 2014 Stage I EOC at our institution. Methods: We retrospectively reviewed the medical records of patients younger than 45 years diagnosed with FIGO 2014 Stage I EOC (April 2010-June 2024). Patients were categorized into FSS (n=11) and non-FSS (n=9) groups. Baseline characteristics, recurrence rates, progression-free survival (PFS), and overall survival (OS) were compared. Results: Twenty patients were included. The FSS group was significantly younger (median age 29.2 vs 40.8 years, p=0.043). Recurrence was more frequent in the FSS group (36.4% vs 11.1%), although this difference was not significant (p=0.077). Kaplan-Meier analysis showed no significant difference in PFS (HR 3.24, 95% CI: 0.56-18.74, p=0.19) or OS (HR 1.78, 95% CI: 0.18-16.9, p=0.63). Conclusion: In this small cohort, FSS for Stage I EOC yielded a higher recurrence rate, but no significant difference in survival, as compared with radical surgery. Because of the small size and inherent stage-migration bias from incomplete surgical staging in the FSS group, these findings should be interpreted with extreme caution. Careful patient selection, thorough staging, and strict surveillance are crucial when implementing FSS.

Background: The global increase in endometrial cancer, including in Japan, and a shortage of pathologists and cytotechnologists have increased the diagnostic burden, emphasizing the need for an AI-based diagnostic support model that uses deep learning. We evaluated the clinical application of an improved AI-supported endometrial cytology model. Methods: Using YOLOv5x and YOLOv7 models evaluated by mean average precision (mAP), we compared two datasets-one annotated for both benign and malignant cell clusters, and one for malignant only. In addition, using the Two One-Sided Tests (TOST) procedure, we assessed the correlation between AI diagnostic accuracy and the level of difficulty perceived by human diagnosticians. Finally, we used Gradient-weighted Class Activation Mapping (Grad-CAM) to visualize and enhance the interpretability of the AI model's decision-making process. Results: The YOLOv5x model with both benign and malignant annotations had the highest malignant mAP, 0.798, as compared with YOLOv7. The TOST analysis showed no significant difference in perceived diagnostic difficulty between cases that were correctly and incorrectly diagnosed by the AI model, indicating consistent AI accuracy regardless of case difficulty. Grad-CAM visualizations clarified the AI model's decision-making basis; in some cases, the model appeared to focus on regions that differed from those typically attended to by human diagnosticians. Conclusion: The AI support model showed high and consistent accuracy in endometrial cytological analysis, regardless of diagnostic difficulty as perceived by human diagnosticians. Grad-CAM visualizations revealed diagnostic patterns, and the AI occasionally focused on regions different from those emphasized by human diagnosticians. This study advanced a real-time microscope-integrated AI system toward clinical application.

Allergic reactions during chemotherapy can lead to a rare condition known as Kounis syndrome, characterized by the simultaneous occurrence of coronary ischemia and allergic manifestations. Herein, we present a case of a 75-year-old woman who developed carboplatin-induced coronary vasospasm, highlighting the importance of comprehensive clinical and immunological evaluations for an accurate diagnosis. During carboplatin infusion, the patient exhibited typical symptoms, including chest pain and electrocardiographic changes. Subsequent investigations revealed elevated serum tryptase and total immunoglobulin E levels along with normal-looking coronary arteries, confirming a diagnosis of Type I Kounis syndrome. Following a safe recovery from the acute anaphylactic episode, the patient's treatment plan was adjusted accordingly based on this definitive diagnosis. Our findings emphasize the significance of recognizing and documenting immune responses in the diagnosis of Kounis syndrome; this can inform therapeutic strategies and improve patient outcomes.

Metastatic breast tumors are rare and often misdiagnosed as primary breast cancer. Herein, we present a case of breast metastasis from malignant melanoma. A 46-year-old woman presented to our department with a lump in her left breast. Examination revealed a relatively soft mass measuring 4 cm in diameter in the left breast. A needle biopsy was performed, and immunostaining for S-100, human melanoma black-45, CD56/neural cell adhesion molecule, and Melan-A confirmed a diagnosis of malignant melanoma. The metastasis was confined to the breast and was thus treated by surgery to excise the tumor. Malignant melanoma is a rare disease in the Japanese population and is associated with a poor prognosis because of the risk of early metastasis to multiple organs and lymph nodes. However, when complete resection of distant metastases is feasible, curative resection may be indicated. Herein, we report a case of breast metastasis from malignant melanoma and review previously published case reports on this rare condition.

Although lipoma is the most common soft tissue tumor, lipoma in the infrapatellar fat pad (IFP) is rare. Herein, we report three cases of lipoma in the IFP that penetrated the joint capsule and extended subcutaneously. All patients presented with unusual MRI findings. Patients 1, 2, and 3 were 63, 74, and 64 years old, respectively, and all were female. Their chief complaint was a knee mass; however, they did not experience pain or limitations in range of motion. The interval from initial awareness of the mass to first consultation was long (3, 8, and 13 years, respectively). MRI revealed that the mass had extended subcutaneously from the IFP through the lateral, medial, and bilateral joint capsules of the patellar tendon, respectively. On MRI, the masses appeared as lipomatous tumors with scattered low signal areas on T1-weighted imaging. The tumors excised after biopsy had long axes of approximately 6, 7, and 7 cm, respectively. Histological examination revealed lipomas with partial fibrosis in all three tumors and cartilage metaplasia in the tumor from patient 3. Lipomas in IFPs often exhibit secondary changes, such as fibrosis and cartilage metaplasia, resulting in MRI findings that differ from those of typical lipomas. In the present cases, biopsy was necessary to differentiate them from atypical lipomatous tumors or Hoffa disease.