Simple renal cysts are commonly acquired benign lesions of the kidney. Requiring management only when it causes pain, obstruction, or gross hematuria, endoscopic marsupialization of simple renal cysts is a new method for the management of renal cysts. Herein, we present a rare case of a 44-year-old female with a simple renal cyst that was managed for the first time in Saudi Arabia by endoscopic marsupialization and discuss its efficacy and outcome compared to other methods of management.

Renal vein thrombosis (RVT) is not an uncommon condition in patients occurring nephrotic syndrome. Renal cyst by bacterial infection is also rare. Only one case for RVT complicated with infected renal cyst is reported in the English literature. A 78-year-old female was admitted for fever and drowsy mentality for 4 days. Contrast-enhanced computed tomography (CECT) of the abdomen showed 3.7 cm sized irregular shaped exophytic cyst well enhanced in left kidney upper pole and the left RVT. The culture of cystic fluid revealed Klebsiella pneumoniae. Our patient was effectively treated with antibiotics for 8 weeks and anticoagulant for 12 weeks. At 12-week follow-up, CECT of the kidney showed decreased cyst and nearly disappeared RVT. The possibility of RVT in patients with renal cyst infection by bacteria warrants consideration.

BACKGROUND: Renal Osseous Metaplasia (OM) is a rare condition in which mature bone forms within the renal parenchyma, typically as focal cortical lesions. Although it is usually considered a spontaneous and less pathologically significant lesion, it has been observed in damaged renal allografts and other urinary tract sites. The case we present involves a native kidney with a simple renal cyst, where histopathological examination post-tumor enucleation revealed OM, emphasizing its noteworthy presence in clinical settings.
METHODS: A 37-year-old female with a history of cesarean delivery and recent emergency surgery presented with abdominal and left flank pain. Initial ultrasound revealed a 4.2 cm anechoic cyst in the lower pole of the left kidney, which was confirmed by abdominal computed tomography (CT-scan as a well-defined fluid density cyst with a thick calcified wall. Surgical enucleoresection identified a Stoney hard mass with a unilocular cyst, histopathologically diagnosed as a simple renal cyst with metaplastic bone and hematopoietic elements. The patient had an uneventful postoperative course and remained well during the follow-up.
CONCLUSIONS: Osseous metaplasia (OM) involves extraskeletal bone formation and is associated with factors such as chronic ischemia and inflammation. While rare in renal pathology, it occurs in native kidneys, damaged renal allografts, and the urinary tract, posing radiological challenges in differentiating it from calcification. Accurate diagnosis requires histopathological examination because of the difficulties in distinguishing OM from calcification on imaging studies.
CONCLUSIONS: This case revealed Osseous Metaplasia in a simple cyst of the native kidney, urging vigilance in the diagnosis. While generally benign, its occurrence in damaged renal areas emphasizes its clinical significance, prompting further research. Heightened awareness and thorough examination are crucial for accurate diagnosis and patient management.

Juvenile nephronophthisis is an inherited renal ciliopathy with cystic kidney disease, renal fibrosis, and end-stage renal failure in children and young adults. Mutations in the NPHP1 gene encoding nephrocystin-1 protein have been identified as the most frequently responsible gene and cause the formation of cysts in the renal medulla. The molecular pathogenesis of juvenile nephronophthisis remains elusive, and no effective medicines to prevent end-stage renal failure exist even today. No human cellular models have been available yet. Here, we report a first disease model of juvenile nephronophthisis using patient-derived and gene-edited human induced pluripotent stem cells (hiPSCs) and kidney organoids derived from these hiPSCs. We established NPHP1-overexpressing hiPSCs from patient-derived hiPSCs and NPHP1-deficient hiPSCs from healthy donor hiPSCs. Comparing these series of hiPSCs, we found abnormalities in primary cilia associated with NPHP1 deficiency in hiPSCs. Kidney organoids generated from the hiPSCs lacking NPHP1 formed renal cysts frequently in suspension culture with constant rotation. This cyst formation in patient-derived kidney organoids was rescued by overexpression of NPHP1. Transcriptome analysis on these kidney organoids revealed that loss of NPHP1 caused lower expression of genes related to primary cilia in epithelial cells and higher expression of genes related to the cell cycle. These findings suggested the relationship between abnormality in primary cilia induced by NPHP1 loss and abnormal proliferative characteristics in the formation of renal cysts. These findings demonstrated that hiPSC-based systematic disease modeling of juvenile nephronophthisis contributed to elucidating the molecular pathogenesis and developing new therapies.

UNASSIGNED: There is lack of discrimination as to traditional imaging diagnostic methods of cystic renal lesions (CRLs). This study aimed to evaluate the value of machine learning models based on clinical data and contrast-enhanced computed tomography (CECT) radiomics features in the differential diagnosis of benign and malignant CRL.
UNASSIGNED: There were 192 patients with CRL (Bosniak class ≥ II) enrolled through histopathological examination, including 144 benign cystic renal lesions (BCRLs) and 48 malignant cystic renal lesions (MCRLs). Radiomics features were extracted from CECT images taken during the medullary phase. Using the light gradient boosting machine (LightGBM) algorithm, the clinical, radiomics and combined models were constructed. A comprehensive nomogram was developed by integrating the radiomics score (Rad-score) with independent clinical factors. Receiver operating characteristic (ROC) curves were plotted. The corresponding area under the curve (AUC) value was worked out to quantify the discrimination performance of the three models in training and validation cohorts. Calibration curves were worked out to assess the accuracy of the probability values predicted by the models. Decision curve analysis (DCA) was worked out to assess the performance of models at different thresholds.
UNASSIGNED: Maximum diameter and Bosniak class were independent risk factors of patients with MCRL in the clinical model. Twenty-one radiomics features were extracted to work out a Rad-score. The performance of the clinical model in the training cohort was AUC =0.948, 95% confidence interval (CI): 0.917-0.980, and the performance in the validation cohort was AUC =0.936, 95% CI: 0.859-1.000 (P<0.05). The performance of the radiomics model in the training cohort was AUC =0.990, 95% CI: 0.979-1.000, and the performance in the validation cohort was AUC =0.959, 95% CI: 0.903-1.000 (P<0.05). Compared with the above models, the combined radiomics nomogram had an AUC of 0.989 (95% CI: 0.977-1.000) in the training cohort and an AUC of 0.962 (95% CI: 0.905-1.000) in the validation cohort (P<0.05), showing the best diagnostic efficacy.
UNASSIGNED: The radiomics nomogram integrating clinical independent risk factors and radiomics signature improved the diagnostic accuracy in differentiating between BCRL and MCRL, which can provide a reference for clinical decision-making and help clinicians develop individualized treatment strategies for patients.

BACKGROUND: Incidental findings are unrelated to a patient\'s complaint, found on diagnostic imaging, such as point-of-care ultrasound (POCUS). Incidental findings represent potential harms to patients and may lead to increased patient anxiety and health care costs related to downstream testing and surveillance.
OBJECTIVE: In this study, we aimed to calculate the rate of incidental renal cysts found by POCUS. Further, we hoped to describe how emergency physicians relay the findings to patients. Lastly, we hoped to examine if patients suffered harms in the 12 months following identification of an incidental renal cyst.
METHODS: From our single-center, academic emergency department (ED), we reviewed renal POCUS images from 1000 consecutive adult ED patients to determine if there was a renal cyst. Next, we performed manual chart review to determine if patients were informed of the incidental renal cyst or suffered any patient harms.
RESULTS: We found the prevalence of renal cysts to be 6.5% (95% confidence interval: 4.9%-8.4%). Those with cysts were more likely to be older compared to those without (63 ± 14 vs. 49 ± 15 years of age). Only 8% of patients had evidence that they were informed of their incidental renal cyst. No patients received a biopsy or were diagnosed with renal cell carcinoma or polycystic kidney disease.
CONCLUSIONS: Incidental renal cysts are common and are more likely to be found in older adults. In our study, physicians infrequently informed patients of their incidental finding.

Standard ultrasound (US) finds wide use in renal diseases as a screening procedure, but it is not always able to characterize lesions, especially in differential diagnosis between benign and malignant lesions. In contrast, contrast-enhanced ultrasonography (CEUS) is appropriate in differentiating between solid and cystic lesions as well as between tumors and pseudotumors. We show the case of a nephropathic patient who showed a complex, large, growing renal mass, characterized through a CEUS. This seventy-five-year-old diabetic heart patient showed a 6 cm-complex and plurisected cyst on ultrasound of left kidney. Laboratory data showed the presence of stage IIIb chronic renal failure with GFR 30 ml/min, creatinine 2.33 mg/dl, azotemia 88 mg/dl. The patient performed abdominal CT without contrast medium, showing at the level of the left upper pole, a roundish formation with the dimensions of approximately 70x53x50 mm. At the semiannual checkup, the nephrology examination showed a slight rise in creatinine and, therefore, after six months, it was decided to perform a CT scan without contrast medium again. CT showed a slight increase in the size of the mass located at the left kidney (74x56x57 mm). Given the increased size of the left mass, albeit modest, a CEUS was performed to reach a diriment diagnosis. CEUS concluded for complex cystic formation with presence of intraluminal solid-corpuscular material, with thrombotic-hemorrhagic etiology, in progressive phase of organization, classifiable as Bosniak type II cyst. CEUS in the kidneys is a cost-effective and valuable imaging technique; it is accurate in the characterization of indeterminate lesions and complex cysts.

Syncope is a commonly encountered symptom that accounts for up to 3% of all emergency department visits in the United States [1]. The differential diagnosis for patients presenting with syncope is often broad and can involve multiple distinct organ systems. This case details the hospital course of an 83-year-old male with a complicated past medical history who initially presented for syncope. Following an extensive work up it was eventually elicited that this patient had an unusual etiology of syncope, a 19 cm x 24 cm renal cyst that was compressing the inferior vena cava (IVC).

BACKGROUND: The aim of this study was to explore the safety and feasibility of single-port nephroscopy combined with a needle electrode technique to unroof single dorsal simple renal cysts (SRCs).
METHODS: This was a retrospective analysis of the clinical data for 18 patients with single dorsal SRCs treated with single-port nephroscopy and a needle electrode technique at Zhongshan City People\'s Hospital from August 2021 to August 2022. The basic information included the cyst condition, surgical methods and recurrence rate, and follow-up was conducted with CT imaging.
RESULTS: The surgery was successful in all 18 patients. The duration of surgery ranged from 24 to 46 min, with an average of 35.83 ± 1.62 min; the intraoperative bleeding volume ranged from 2 to 20 mL, with an average of 9.0 ± 1.3 mL; and the visual analog scale (VAS) score within 24 h after surgery ranged from 1 to 6 points, with an average of 2.72 ± 0.36 points. There were no significant postoperative complications, such as bleeding, urinary fistula, or infection. All drainage tubes were removed on the first day after surgery. After 1 year of postoperative follow-up, 1 patient experienced recurrence, for a recurrence rate of 5.6%.
CONCLUSIONS: Single-port nephroscopy combined with a needle electrode technique is a safe, feasible, and effective minimally invasive surgical approach for treating single dorsal SRCs.

This report describes the diagnosis and treatment of a benign renal cyst in an adult, female golden eagle (Aquila chrysaetos) presented for unilateral leg lameness. A cyst at the cranial division of the left kidney was diagnosed by computed tomography and was suspected of compressing the lumbosacral nerve plexus, resulting in limb lameness. The renal cyst was incompletely excised because the cyst wall was closely adhered to the kidney parenchyma and local blood supply. Fluid analysis and surgical biopsy of the cyst and left kidney confirmed the diagnosis of a benign renal cyst. No evidence of an infectious, inflammatory, or neoplastic etiology was noted. Postoperatively, the eagle\'s lameness resolved and the bird was ultimately released following recovery. During treatment for the renal cyst, the eagle was concurrently found to have increased serum titers on elementary body agglutination for Chlamydia psittaci and a positive titer for Aspergillus species antibody testing. The bird was administered doxycycline, azithromycin, and voriconazole for treatment of these potential pathogens prior to release. Unfortunately, the eagle was found dead 86 days postrelease due to an unknown cause. To the authors\' knowledge, this is the first report of a golden eagle with a benign solitary renal cyst causing unilateral lameness secondary to nerve compression that was resolved with surgical excision.