Breast cancer is the most common cancer among women worldwide. Breast cancer often metastasizes to the regional lymph nodes, bone, brain, liver, and lungs, whereas gastrointestinal tract metastases are rare. Herein, we present a rare case of rectal metastasis from breast cancer that occurred during palliative chemotherapy. A 69-year-old female with a history of invasive ductal carcinoma, negative for hormonal receptors and positive for human epidermal growth factor receptor 2 (HER2) receptor, underwent various treatments, including neoadjuvant chemotherapy, breast-conserving surgery, and adjuvant therapy. Eight months postoperatively, the patient experienced axillary lymph node recurrence, requiring palliative chemotherapy. Despite ongoing treatment, metastatic lesions were confirmed in the lungs and pleura. During palliative chemotherapy, the patient developed anal pain, and subsequent examination revealed an infiltrating rectal lesion. Despite histological confirmation of metastatic breast carcinoma and tubular adenoma, a multidisciplinary decision was made regarding palliative chemotherapy over surgical intervention. Eribulin was administered, but due to the patient’s inability to tolerate the treatment, she passed away 3 months after rectal lesion diagnosis. Although breast cancer metastasis to the rectum is rare, clinicians should consider the possibility of rectal involvement and perform a digital rectal examination if anal symptoms are present.

Subclinical hypothyroidism (SCH), characterized by elevated serum thyroid-stimulating hormone (TSH) levels and normal free thyroxine levels, usually presents without symptoms, and is often discovered incidentally during routine blood test. The Task Force of the Korean Thyroid Association Committee of Clinical Practice Guidelines has established a guideline to evaluate and manage SCH; the guideline emphasizes the implementation of diagnostic criteria based on the TSH reference range for Koreans and focuses on the proven health benefits of levothyroxine (LT4) treatment. Based on the Korea National Health and Nutrition Examination Survey (2013-2015), serum TSH level of 6.8 mIU/L is considered the reference value for SCH. SCH can be categorized as mild (TSH 6.8-10.0 mIU/L) or severe (TSH ＞10.0 mIU/L), and patients are classified as adults (age ＜70 years) or elderly patients (age ≥70years) depending on the health effects of LT4 treatment. An initial increase in serum TSH levels should be reassessed with a subsequent measurement, along with the thyroid peroxidase antibody test, preferably 2-3 months after the initial evaluation. Usually, LT4 treatment is not recommended for mild SCH in adults; however, treatment is necessary for severe SCH in patients with underlying coronary artery disease or heart failure and can be considered for coexisting dyslipidemia. LT4 treatment is not recommended for mild or even severe SCH in elderly patients, in general. Patients with SCH who receive LT4 treatment, the LT4 dosage should be personalized, and serum TSH levels should be monitored to ensure optimal LT4 dosage (dosage that is neither excessive nor insufficient). Patients with SCH who do not receive LT4 treatment require periodic follow-up at appropriate testing intervals determined by disease severity. The guideline also provides several educational points applicable in clinical settings.

Purpose: We aimed to investigate manifestations and patterns of care for patients with brain metastasis (BM) from breast cancer (BC) and compared their overall survival (OS) from 2005 through 2014 in Korea. Materials and Methods: We retrospectively reviewed 600 BC patients with BM diagnosed between 2005 and 2014. The median follow-up duration was 12.5 months. We categorized the patients into three groups according to the year when BM was initially diagnosed (group I [2005-2008], 98 patients; group II [2009-2011], 200 patients; and group III [2012-2014], 302 patients). Results: Over time, the median age at BM diagnosis increased by 2.2 years (group I, 49.0 years; group II, 48.3 years; and group III, 51.2 years; p=0.008). The percentage of patients with extracranial metastasis was 73.5%, 83.5%, and 86.4% for group I, II, and III, respectively (p=0.011). The time interval between BC and BM was prolonged in patients with stage III primary BC (median, 2.4 to 3 years; p=0.029). As an initial brain-directed treatment, whole-brain radiotherapy alone decreased from 80.0% in 2005 to 41.1% in 2014. Meanwhile, stereotactic radiosurgery or fractionated stereotactic radiotherapy alone increased from 13.3% to 34.7% during the same period (p=0.005). The median OS for group I, II, and III was 15.6, 17.9, and 15.0 months, respectively, with no statistical significance. Conclusion The manifestations of BM from BC and the pattern of care have changed from 2005 to 2014 in Korea. However, the OS has remained relatively unchanged over the 10 years.

Background: Since image-based fracture prediction models using deep learning are lacking, we aimed to develop an X-ray-based fracture prediction model using deep learning with longitudinal data. Methods: This study included 1,595 participants aged 50 to 75 years with at least two lumbosacral radiographs without baseline fractures from 2010 to 2015 at Seoul National University Hospital. Positive and negative cases were defined according to whether vertebral fractures developed during follow-up. The cases were divided into training (n=1,416) and test (n=179) sets. A convolutional neural network (CNN)-based prediction algorithm, DeepSurv, was trained with images and baseline clinical information (age, sex, body mass index, glucocorticoid use, and secondary osteoporosis). The concordance index (C-index) was used to compare performance between DeepSurv and the Fracture Risk Assessment Tool (FRAX) and Cox proportional hazard (CoxPH) models. Results: Of the total participants, 1,188 (74.4%) were women, and the mean age was 60.5 years. During a mean follow-up period of 40.7 months, vertebral fractures occurred in 7.5% (120/1,595) of participants. In the test set, when DeepSurv learned with images and clinical features, it showed higher performance than FRAX and CoxPH in terms of C-index values (DeepSurv, 0.612; 95% confidence interval [CI], 0.571 to 0.653; FRAX, 0.547; CoxPH, 0.594; 95% CI, 0.552 to 0.555). Notably, the DeepSurv method without clinical features had a higher C-index (0.614; 95% CI, 0.572 to 0.656) than that of FRAX in women. Conclusion DeepSurv, a CNN-based prediction algorithm using baseline image and clinical information, outperformed the FRAX and CoxPH models in predicting osteoporotic fracture from spine radiographs in a longitudinal cohort.

Salmonella enterica serotype Choleraesuis causes swine paratyphoid, with clinical findings of enterocolitis and septicemia. However, the clinicopathological features of S. Choleraesuis infections in pigs have not been reported in Korea. We describe the pathological findings of two weaned pigs with S. Choleraesuis infections, presenting with diarrhea, cough, and sudden death. Pathological examination indicated severe necrotic colitis in pig 1 and septicemic lesions in pig 2. Multidrug-resistant S. Choleraesuis was isolated from the pigs’ lungs and intestinal contents. Further research is required for the surveillance of S. Choleraesuis infections in pigs and the virulence estimation in the S. Choleraesuis isolates.

Objective: The purpose of this study was to investigate the differences in the characteristics between rental car crashes and non-rental car crashes on Jeju Island, and to investigate the association between rental car crashes and the severity of injuries. Methods: This study analyzed data on traffic accidents that occurred on Jeju Island, South Korea from January 2010 to December 2019. The data on traffic accident-related factors were collected using the Traffic Accident Analysis System operated by the Road Traffic Authority. The primary outcome was a fatal injury and secondary outcomes were severe and minor injuries. We analyzed the differences in the characteristics of each factor between rental car crashes and nonrental crashes. We also analyzed the correlation between rental car accidents and the outcome variables. Results: A total of 40,713 traffic accidents occurred during the study period, of which 4,601 (11.3%) were rental car crashes and 36,112 (88.7%) were non-rental crashes. In the rental car crash group, the proportions of the 20-30s age group and female drivers were higher; however, the proportion of the risky driving behaviors was lower. Also, the incidence rate in summer and daytime was higher, and the proportions of vehicle-to-vehicle crashes, single vehicle crashes, and head-on collisions were higher. According to the results of the Poisson regression test, the rental car crash group showed a higher risk of severe injuries (adjusted incidence rate ratio, 1.07; 95% confidence interval, 1.01-1.14), but there was no significant difference in their risk of fatal injuries. Conclusion Our results suggest the need for traffic accident prevention programs considering the characteristics of rental car crashes on Jeju Island, South Korea.

Background/Aims: Acute kidney injury (AKI) is an underestimated yet important risk factor for the development of chronic kidney disease (CKD), characterized by tubulointerstitial fibrosis and tubular dedifferentiation. Tubular dedifferentiation, which is associated with the loss of epithelial markers and the gain of mesenchymal features, is thought to be involved in tubulointerstitial fibrosis. As protein kinase B/Akt is involved in the development of CKD, we investigated the role of Akt1, one of the three Akt isoforms, in a murine model of AKI-to-CKD progression. Methods: We subjected C57BL/6 male mice to unilateral ischemia-reperfusion injury (UIRI) and harvested their kidneys after 6 weeks. Mice were divided into four groups, namely, wild-type (WT) UIRI, Akt1−/− UIRI, WT sham, and Akt1−/− sham. Results: Akt1 (but not Akt2 or Akt3) was markedly activated in WT UIRI mice than in WT sham mice. Tubulointerstitial fibrosis and tubular dedifferentiation significantly increased in WT UIRI mice, but were attenuated in Akt1−/− UIRI mice. Both WT UIRI and Akt1−/− UIRI mice showed markedly upregulated transforming growth factor-β1 (TGF-β1)/Smad signaling compared with WT sham mice. However, TGF-β1/Smad expression did not differ between the two groups. The levels of phosphorylated GSK-3β, β-catenin, and Snail were attenuated in Akt1−/− UIRI mice compared with those in WT UIRI mice. Conclusions Deletion of Akt1 results in the attenuation of renal fibrosis and tubular dedifferentiation, independent of TGF-β1/Smad signaling, during AKI-to-CKD progression in a UIRI without contralateral nephrectomy model. Thus, Akt1 may serve as a therapeutic target in AKI-to-CKD progression.

Objective: This study aimed to determine whether there is a difference in mortality and medical resource utilization between geriatric (aged ≥65 years) and super-geriatric patients (aged ≥80 years) with traumatic brain injury (TBI). Methods: We obtained comprehensive data (demographics, injury characteristics, injury severities, and outcomes) of geriatric and super-geriatric TBI patients from an emergency department-based injury surveillance system database from 2011 to 2016. Multivariate logistic regression analysis was performed to compare the mortality and nonroutine discharge (NRDC) status between both groups. Results: Among 442,533 TBI patients, 48,624 were older than 65 years. A total of 48,446 patients (37,140 geriatric and 11,306 super-geriatric) without exclusion criteria were included in the final analysis. Both overall in-hospital mortality (adjusted odds ratio, 1.88; 95% confidence interval [CI], 1.28 to 2.74; P=0.001) and NRDC (adjusted odds ratio, 1.35; 95% CI, 1.07 to 1.71; P=0.011) were significantly higher in the super-geriatric group. In the stratified analysis, there were no significant differences in NRDC rate for all stratifications of treatment timing (emergency department vs. ward admission), but mortality remained to be significant for all stratifications. Conclusion Super-geriatric TBI patients showed a significantly higher risk-adjusted overall mortality and more inadequate medical resource utilization than did geriatric TBI patients. However, super-geriatric patients were more likely to undergo NRDC after admission; thus, further research about age-related health inequalities is needed in the treatment of super-geriatric patients.

Arachnoid web is a very rare disease that occurs when the normal flow of cerebrospinal fluid is disturbed due to abnormal formation of the arachnoid membrane in the arachnoid space. Consequently, symptoms appear in the form of various myelopathies, such as loss of strength and sensation in the upper and lower extremities, or bladder control disorders. In general, surgical treatment can be considered if symptoms are exhibited. Arachnoid web requires a high consideration of appropriate diagnosis and treatment methods. However, due to its extremely rare occurrence in actual clinical practice, it is difficult to differentiate from other diseases such as herniated intervertebral disc or subdural tumor causing spinal myelopathy. This would effectively lead to a completely different direction of treatment. To date, there have been no case reports of Arachnoid web in Korea, except for collecting and reporting the focal anterior displacement of the thoracic spine, which is a similar lesion in the spinal cord. This article therefore provides information through case reports and literature review.