The Urothelium: Life in a Liquid Environment.

The urothelium, which lines the renal pelvis, ureters, urinary bladder, and proximal urethra, forms a high-resistance but adaptable barrier that surveils its mechanochemical environment and communicates changes to underlying tissues including afferent nerve fibers and the smooth muscle. The goal of this review is to summarize new insights into urothelial biology and function that have occurred in the past decade. After familiarizing the reader with key aspects of urothelial histology, we describe new insights into urothelial development and regeneration. This is followed by an extended discussion of urothelial barrier function, including information about the roles of the glycocalyx, ion and water transport, tight junctions, and the cellular and tissue shape changes and other adaptations that accompany expansion and contraction of the lower urinary tract. We also explore evidence that the urothelium can alter the water and solute composition of urine during normal physiology and in response to overdistension. We complete the review by providing an overview of our current knowledge about the urothelial environment, discussing the sensor and transducer functions of the urothelium, exploring the role of circadian rhythms in urothelial gene expression, and describing novel research tools that are likely to further advance our understanding of urothelial biology.

Identifying peristaltic pacemaker cells in the upper urinary tract.

Urine expulsion from the upper urinary tract is a necessary process that eliminates waste, promotes renal filtration and prevents nephron damage. To facilitate the movement of urine boluses throughout the upper urinary tract, smooth muscle cells that line the renal pelvis contract in a coordinated effort to form peristaltic waves. Resident pacemaker cells in the renal pelvis are critical to this process and spontaneously evoke transient depolarizations that initiate each peristaltic wave and establish rhythmic contractions. Renal pacemakers have been termed atypical smooth muscle cells due to their low expression of smooth muscle myosin and poor organization of myofilaments compared to typical (or contractile) smooth muscle cells that perform peristalsis. Recent findings discovered that pacemaker cells also express the tyrosine kinase receptor PDGFRα, enabling their identification and purification amongst other renal pelvis cell types. Improved identification methods have determined that the calcium-activated chloride channel, ANO1, is expressed by pacemaker cells and may contribute to spontaneous depolarization. A greater understanding of pacemaker and peristaltic mechanisms is warranted since aberrant contractile function may underlie diseases such as hydronephrosis, a deleterious condition that can cause significant and irreversible nephron injury.

The impact of siphoning effect on renal pelvis pressure during ureteroscopy using an in vitro kidney and ureter model.

PURPOSE: To experimentally measure renal pelvis pressure (PRP) in an ureteroscopic model when applying a simple hydrodynamic principle, the siphoning effect. METHODS: A 9.5Fr disposable ureteroscope was inserted into a silicone kidney-ureter model with its tip positioned at the renal pelvis. Irrigation was delivered through the ureteroscope at 100 cm above the renal pelvis. A Y-shaped adapter was fitted onto the model's renal pelvis port, accommodating a pressure sensor and a 4 Fr ureteral access catheter (UAC) through each limb. The drainage flowrate through the UAC tip was measured for 60 s each run. The distal tip of the UAC was placed at various heights below or above the center of the renal pelvis to create a siphoning effect. All trials were performed in triplicate for two lengths of 4Fr UACs: 100 cm and 70 cm (modified from 100 cm). RESULTS: PRP was linearly dependent on the height difference from the center of the renal pelvis to the UAC tip for both tested UAC lengths. In our experimental setting, PRP can be reduced by 10 cmH20 simply by lowering the distal tip of a 4 Fr 70 cm UAC positioned alongside the ureteroscope by 19.7 cm. When using a 4 Fr 100 cm UAC, PRP can drop 10 cmH20 by lowering the distal tip of the UAC 23.3 cm below the level of the renal pelvis. CONCLUSION: Implementing the siphoning effect for managing PRP during ureteroscopy could potentially enhance safety and effectiveness.

Mesenchymal stem cells and their extracellular vesicles in urological cancers: Prostate, bladder, and kidney.

Mesenchymal stem cells (MSCs) are recognized for their remarkable ability to differentiate into multiple cell types. They are also known to possess properties that can fight cancer, leading to attempts to modify MSCs for use in anticancer treatments. However, MSCs have also been found to participate in pathways that promote tumor growth. Many studies have been conducted to explore the potential of MSCs for clinical applications, but the results have been inconclusive, possibly due to the diverse nature of MSC populations. Furthermore, the conflicting roles of MSCs in inhibiting tumors and promoting tumor growth hinder their adaptation to anticancer therapies. Antitumorigenic and protumorigenic properties of MSCs in urological cancers such as bladder, prostate, and renal are not as well established, and data comparing them are still limited. MSCs hold significant promise as a vehicle for delivering anticancer agents and suicide genes to tumors. Presently, numerous studies have concentrated on the products derived from MSCs, such as extracellular vesicles (EVs), as a form of cell-free therapy. This work aimed to review and discuss the current knowledge of MSCs and their EVs in urological cancer therapy.

Focus on Upper Urinary Tract Stones Combined with Parenchymal Infiltrative Renal Pelvis Cancer.

INTRODUCTION: Upper urinary tract stones combined with parenchymal infiltrative renal pelvic cancer are challenging to detect on imaging and to evaluate the differential diagnosis. CASE PRESENTATION: The symptoms and diagnoses in three cases of parenchymal infiltrative renal pelvic cancer and upper urinary tract stones that occurred between June 2019 and June 2022 were reviewed. Primary symptoms of lumbar discomfort and hematuria were evident in all 3 patients. Preoperative computed tomography (CT) abdominal imaging revealed that all three cases had hydronephrosis along with renal stones, while the other two cases only had localized hypoenhancement of the renal parenchyma, which was only thought to be limited inflammatory changes in the renal cortex as a result of the combination of renal pelvis infection. After percutaneous nephrolithotomy or ureteroscopic lithotripsy, a combined renal pelvis tumor was discovered in all of these instances. Radical tumor surgery was later performed. One patient who had several tumor metastases passed away 6 months after surgery. A case with multiple metastases was discovered 15 months after surgery and survived with the help of the current chemotherapy. A case with a bladder tumor recurrence was discovered 16 months after surgery and had transurethral bladder tumor electrosurgery and routine bladder perfusion chemotherapy. CONCLUSION: Upper urinary tract stones and parenchymal infiltrative pyel carcinoma have atypical imaging, easily confused with infectious diseases. CT or computed tomography urography (CTU) must be considered by urologists. Patients who have a CT with local renal parenchyma density should be suspected of having parenchymal invasive renal pelvis carcinoma; a needle biopsy ought to be performed; and repeat biopsies may be performed if necessary. High-risk individuals need multiple, sufficient biopsies as needed and a comprehensive intraoperative assessment of the renal pelvic mucosa.

Primary mucinous tumors of the renal pelvis: Clinical, histopathological, and molecular analysis of three cases.

Primary mucinous tumors of the renal pelvis are extremely rare and pose challenges in terms of diagnosis and treatment. This study reviewed the clinical and pathological characteristics of mucinous tumors of the renal pelvis, including mucinous cystadenocarcinomas and mucinous cystadenomas. Immunohistochemical analysis was conducted in three cases, along with KRAS gene detection using the Amplification Refractory Mutation System (ARMS) method. The results revealed mucinous epithelium with acellular mucinous pools in all cases, and acellular mucinous pools were observed in the renal parenchyma and perirenal fat capsules. All tumors expressed CK20 and CDX2, and one case showed KRAS gene mutation. The study suggests that mucinous cystadenomas of the renal pelvis may exhibit borderline biological behaviors. This study is the first to report a KRAS gene mutation in a mucinous cystadenoma of the renal pelvis, offering valuable insights into the diagnosis and treatment of this rare condition.

An evolutionarily conserved pacemaker role for HCN ion channels in smooth muscle.

Although hyperpolarization-activated cation (HCN) ion channels are well established to underlie cardiac pacemaker activity, their role in smooth muscle organs remains controversial. HCN-expressing cells are localized to renal pelvic smooth muscle (RPSM) pacemaker tissues of the murine upper urinary tract and HCN channel conductance is required for peristalsis. To date, however, the Ih pacemaker current conducted by HCN channels has never been detected in these cells, raising questions on the identity of RPSM pacemakers. Indeed, the RPSM pacemaker mechanisms of the unique multicalyceal upper urinary tract exhibited by humans remains unknown. Here, we developed immunopanning purification protocols and demonstrate that 96% of isolated HCN+ cells exhibit Ih . Single-molecule STORM to whole-tissue imaging showed HCN+ cells express single HCN channels on their plasma membrane and integrate into the muscular syncytium. By contrast, PDGFR-α+ cells exhibiting the morphology of ICC gut pacemakers were shown to be vascular mural cells. Translational studies in the homologous human and porcine multicalyceal upper urinary tracts showed that contractions and pacemaker depolarizations originate in proximal calyceal RPSM. Critically, HCN+ cells were shown to integrate into calyceal RPSM pacemaker tissues, and HCN channel block abolished electrical pacemaker activity and peristalsis of the multicalyceal upper urinary tract. Cumulatively, these studies demonstrate that HCN ion channels play a broad, evolutionarily conserved pacemaker role in both cardiac and smooth muscle organs and have implications for channelopathies as putative aetiologies of smooth muscle disorders. KEY POINTS: Pacemakers trigger contractions of involuntary muscles. Hyperpolarization-activated cation (HCN) ion channels underpin cardiac pacemaker activity, but their role in smooth muscle organs remains controversial. Renal pelvic smooth muscle (RPSM) pacemakers trigger contractions that propel waste away from the kidney. HCN+ cells localize to murine RPSM pacemaker tissue and HCN channel conductance is required for peristalsis. The HCN (Ih ) current has never been detected in RPSM cells, raising doubt whether HCN+ cells are bona fide pacemakers. Moreover, the pacemaker mechanisms of the unique multicalyceal RPSM of higher order mammals remains unknown. In total, 97% of purified HCN+ RPSM cells exhibit Ih . HCN+ cells integrate into the RPSM musculature, and pacemaker tissue peristalsis is dependent on HCN channels. Translational studies in human and swine demonstrate HCN channels are conserved in the multicalyceal RPSM and that HCN channels underlie pacemaker activity that drives peristalsis. These studies provide insight into putative channelopathies that can underlie smooth muscle dysfunction.

Renal Pelvic Urothelial Carcinoma With Invasion Into Renal Medulla Can Be Redefined as pT2 to Improve Correlation With Survival.

According to the American Joint Cancer Committee, pT3 renal pelvic carcinoma is defined as tumor invading the renal parenchyma and/or peripelvic fat and is the largest pT category, with notable survival heterogeneity. Anatomical landmarks within the renal pelvis can be difficult to discern. Using glomeruli as a boundary to differentiate renal medulla invasion from renal cortex invasion, this study aimed to compare patient survival of pT3 renal pelvic urothelial carcinoma on the basis of the extent of renal parenchyma invasion and, thereafter, determine whether redefining pT2 and pT3 improves pT correlation with survival. Cases with primary renal pelvic urothelial carcinoma were identified through a review of pathology reports from nephroureterectomies completed at our institution from 2010 to 2019 (n = 145). Tumors were stratified by pT, pN, lymphovascular invasion, and invasion of the renal medulla versus invasion of the renal cortex and/or peripelvic fat. Overall survival between groups was compared using Kaplan-Meier survival models and Cox regression multivariate analysis. pT2 and pT3 tumors had similar 5-year overall survival, with multivariate analysis demonstrating an overlap between hazard ratios (HRs) for pT2 (HR, 2.20; 95% CI, 0.70-6.95) and pT3 (HR, 3.15; 95% CI, 1.63-6.09). pT3 tumors with peripelvic fat and/or renal cortex invasion had a 3.25-fold worse prognosis than pT3 tumors with renal medulla invasion alone. Furthermore, pT2 and pT3 tumors with only renal medulla invasion had similar overall survival, whereas pT3 tumors with peripelvic fat and/or renal cortex invasion had a worse prognosis (P = .00036). Reclassifying pT3 tumors with only renal medulla invasion as pT2 yielded greater separation between survival curves and HR. Thus, we recommend redefining pT2 renal pelvic carcinoma to include renal medulla invasion and restricting pT3 to peripelvic fat and/or renal cortex invasion to improve the prognostic accuracy of pT classification.

Diagnosis and Management of Non-Metastatic Upper Tract Urothelial Carcinoma: AUA/SUO Guideline.

PURPOSE: The purpose of this guideline is to provide a useful reference on the effective evidence-based diagnoses and management of non-metastatic upper tract urothelial carcinoma (UTUC). MATERIALS/METHODS: The Pacific Northwest Evidence-based Practice Center of Oregon Health & Science University (OHSU) team conducted searches in Ovid MEDLINE (1946 to March 3rd, 2022), Cochrane Central Register of Controlled Trials (through January 2022), and Cochrane Database of Systematic Reviews (through January 2022). The searches were updated August 2022. When sufficient evidence existed, the body of evidence was assigned a strength rating of A (high), B (moderate), or C (low) for support of Strong, Moderate, or Conditional Recommendations. In the absence of sufficient evidence, additional information is provided as Clinical Principles and Expert Opinions (Table 1).[Table: see text]Results:This Guideline provides updated, evidence-based recommendations regarding diagnosis and management of non-metastatic UTUC including risk stratification, surveillance and survivorship. Treatments discussed include kidney sparing management, surgical management, lymph node dissection (LND), neoadjuvant/adjuvant chemotherapy and immunotherapy. CONCLUSION: This standardized guideline seeks to improve clinicians' ability to evaluate and treat patients with UTUC based on available evidence. Future studies will be essential to further support these statements for improving patient care. Updates will occur as the knowledge regarding disease biology, clinical behavior and new therapeutic options develop.

Clinical outcomes of intraluminal Iodine-125 seed strand brachytherapy and percutaneous nephrostomy in patients with ureteral carcinoma.

BACKGROUND: We aimed to evaluate the safety and efficacy of intraluminal iodine-125 seed strand brachytherapy and percutaneous nephrostomy in patients with ureteral carcinoma. METHODS: From January 2014 to January 2023, 48 patients with ureteral cancer not suitable for surgical resection were enrolled. Iodine-125 seed strand was inserted in 26 patients under c-arm CT and fluoroscopic guidance (Group A), and 22 patients underwent percutaneous nephrostomy without seed strand (Group B). The clinical outcomes (technical success rate, tumor sizes, hydronephrosis Girignon grade, complications, objective response rate (ORR), disease control rate (DCR), and survival time) were evaluated and compared. RESULTS: A total of 53 seed strands were successfully inserted and replaced in Group A, with a technical success rate of 100%. No procedure-related death or severe complications occurred in both group. Migration of seed strand or drainage tube was the most common complication. The Girignon grade of hydronephrosis was significantly improved 1, 3 and 6 months after procedure in both groups. DCR in Group A were 96.2%, 80.0%, and 70.0% at 1-, 3-, and 6-month follow up, respectively. At 1 and 6 months later, ORR in Group A were significantly higher than those in Group B (p < 0.05). The median overall survival were 30.0 months in Group A and 16.1 months in Group B, respectively (p = 0.04). The median progression-free survival were 11.1 months in Group A and 6.9 months in Group B, respectively (p = 0.09). CONCLUSION: Intraluminal Iodine-125 seed strand brachytherapy and percutaneous nephrostomy is safe and effective in patients with ureteral carcinoma, with higher ORR and median overall survival than patients underwent percutaneous nephrostomy without seed strand.

Quantification of outflow resistance for ureteral drainage devices used during ureteroscopy.

PURPOSE: Since renal pelvis pressure is directly related to irrigation flowrate and outflow resistance, knowledge of outflow resistance associated with commonly used drainage devices could help guide the selection of the type and size of ureteral access sheath or catheter for individual ureteroscopic cases. This study aims to quantitatively measure outflow resistance for different drainage devices utilized during ureteroscopy. METHODS: With measured irrigation flowrate and renal pelvis pressure, outflow resistance was calculated using a hydrodynamic formula. After placement of a drainage device into a silicone kidney-ureter model, a disposable ureteroscope with a 9.5-Fr outer diameter was inserted with its tip positioned at the renal pelvis. Irrigation was delivered through the ureteroscope from varying heights above the renal pelvis. Renal pelvis pressure was measured directly from the port of the kidney model using a pressure sensor (Opsens, Canada). Outflow resistance was determined by plotting flowrate versus renal pelvis pressure. All trials were performed in triplicate for each drainage device inserted. RESULTS: Flowrate was linearly dependent on renal pelvis pressure for all drainage devices tested. Outflow resistance values were 0.2, 1.1, 1.4, 3.9, and 6.5 cmH2O/[ml/min] for UAS 13/15 Fr, UAS 11/13 Fr, UAC 6 Fr, UAC 4.8 Fr, and UAC 4.0 Fr, respectively, across the range of commonly used irrigation flowrates. CONCLUSIONS: In this study, outflow resistance of different ureteral drainage devices was quantitatively measured. This knowledge can be useful when selecting which type and size of drainage device to insert to maintain safe renal pelvis pressure during ureteroscopy.

Subclassification of pT3 upper tract urothelial carcinoma: a multicenter retrospective study.

PURPOSE: The prognosis of patients with pT3 upper tract urothelial carcinoma (UTUC) varies. The current study aimed to further classify patients with pT3 UTUC into different survival outcome groups based on tumor location and site of invasion. METHODS: This retrospective study included 323 patients with pT3 UTUC who underwent nephroureterectomy at 11 hospitals in Japan. Histological and clinical data were obtained via a chart review. Univariate and multivariate Cox proportional hazards analyses showed the effect of different variables on recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS). RESULTS: The median age of the patients was 72 years. Patients with pT3 UTUCs were divided into two groups: those with renal parenchymal invasion only (pT3a, n = 95) and those with peripelvic or periureteral fat invasion (pT3b, n = 228). pT3b UTUC was significantly associated with hydronephrosis, low preoperative estimated glomerular filtration rate (eGFR), histological nodal metastasis, nuclear grade 3, lymphovascular invasion (LVI), carcinoma in situ, and positive surgical margin. Based on the univariate analyses, patients with pT3b UTUC had a significantly lower 5-year RFS (42.4% vs. 70.1%, p < 0.0001), 5-year CSS (54.3% vs. 80.0%, p = 0.0002), and 5-year OS (47.8% vs. 76.8%, p < 0.0001) than those with pT3a UTUC. According to the multivariate analyses, nodal metastasis, LVI, adjuvant chemotherapy, preoperative eGFR, nuclear grade (RFS only), surgical margin (RFS only), and Charlson comorbidity index (OS only), but not pT3b stage, were associated with survival. CONCLUSION: Compared with pT3a UTUC, pT3b UTUC was significantly associated with worse histological features, consequently resulting in unsatisfactory survival outcomes.

Upper tract urothelial carcinoma in Germany: epidemiological data and surgical treatment trends in a total population analysis from 2006 to 2019.

PURPOSE: To report contemporary epidemiological data and treatment trends for upper tract urothelial carcinoma (UTUC) in Germany over a 14-year period. METHODS: We analyzed data from the nationwide German hospital billing database and the German cancer registry from 2006 to 2018/2019. The significance of changes over time was evaluated via regression analysis. Survival outcomes were calculated using the Kaplan-Meier method. RESULTS: There was a non-significant increase in the age-standardized incidence rate from 2.5/100,000 in 2006 to 2.9/100.000 in 2018. 13% of patients presented with lymph node metastasis and 7.6% of patients presented with distant metastasis at primary diagnosis. The 5-year overall survival was estimated at 45% and the 10-year overall survival at 32%. Endoscopic biopsies of the renal pelvis and ureter as well as ureteroscopies with excision/destruction of UTUC all increased significantly over the study period. The number of radical nephroureterectomies (RNU) for UTUC steadily increased from 1643 cases in 2006 to 2238 cases in 2019 (p < 0.005) with a shift from open surgery towards minimally invasive surgery. Complex reconstructive procedures like ileal ureter replacement or autotransplantation are rarely performed for urothelial carcinoma of the ureter. CONCLUSION: Diagnostic and therapeutic procedures for UTUC have increased and minimally invasive nephroureterectomy is the predominant approach concerning radical surgery in 2019.

The role of perioperative chemotherapy for upper tract urothelial carcinoma patients treated with radical nephroureterectomy.

PURPOSE: To summarize evidence regarding the use of neoadjuvant (NAC) and adjuvant chemotherapy (AC) among patients treated with radical nephroureterectomy (RNU). METHODS: A comprehensive literature search of PubMed (MEDLINE), EMBASE and the Cochrane library was performed to identify any original or review article on the role of perioperative chemotherapy for UTUC patients treated with RNU. RESULTS: With regards to NAC, retrospective studies consistently suggested that it may be associated with better pathological downstaging (pDS) ranging from 10.8 to 80% and complete response (pCR) ranging from 4.3 to 15%, while decreasing the risk of recurrence and death as compared to RNU alone. Even higher pDS ranging from 58 to 75% and pCR ranging from 14 to 38% were observed in single-arm phase II trials. With regards to AC, retrospective studies provided conflicting results although the largest report from the National Cancer Database suggested an overall survival benefit in pT3-T4 and/or pN + patients. In addition, a phase III randomized controlled trial showed that the use of AC was associated with a disease-free survival benefit (HR = 0.45; 95% CI = [0.30-0.68]; p = 0.0001) in pT2-T4 and/or pN + patients with acceptable toxicity profile. This benefit was consistent in all subgroups analyzed. CONCLUSIONS: Perioperative chemotherapy improves oncological outcomes associated with RNU. Given the impact of RNU on renal function, the rational is stronger for the use of NAC which impacts final pathology and potentially prolongs survival. However, the level of evidence is stronger for the use of AC that has been proven to decrease the risk of recurrence after RNU with a potential survival benefit.

Population characteristics, management, and survival outcomes in muscle-invasive urothelial carcinoma undergoing radical resection: the MINOTAUR study.

PURPOSE: To describe the incidence, management, and survival outcomes of patients with muscle-invasive urothelial carcinoma (MIUC) undergoing radical surgery (RS) in France. METHODS: We relied on a non-interventional real-world retrospective study based on French National Hospitalization Database. Adults with MIUC with a first RS between 2015 and 2020 were selected. Subpopulations of patients with RS performed in 2015 and 2019 (pre-COVID-19) were extracted, according to cancer site: muscle-invasive bladder cancer (MIBC) or upper tract urothelial carcinoma (UTUC). Disease-free and overall survival (DFS, OS - Kaplan-Meier) were assessed on the 2015 subpopulation. RESULTS: Between 2015 and 2020, 21,295 MIUC patients underwent a first RS. Of them, 68.9% had MIBC, 28.9% UTUC, and 2.2% both cancers. Apart from fewer men among UTUC (70.2%) than MIBC patients (90.1%), patients' demographic (mean age ~ 73 years) and clinical characteristics were similar whatever the cancer site or year of first RS. In 2019, RS alone was the most frequent treatment, occurring in 72.3% and 92.6% in MIBC and UTUC, respectively. Between 2015 and 2019, neoadjuvant use rate increased from 13.8% to 22.2% in MIBC, and adjuvant use rate increased from 3.7% to 6.3% in UTUC. Finally, median [95% confidence interval] DFS times were 16.0 [14.0-18.0] and 27.0 [23.0-32.0] months among MIBC and UTUC, respectively. CONCLUSION: Among patients with resected MIUC annually, RS alone remained the main treatment. Neoadjuvant and adjuvant use increased between 2015 and 2019. Nonetheless, MIUC remains of poor prognosis, highlighting an unmet medical need, notably among patients at high risk of recurrence.

Hydrostatic pressure of the renal pelvis as a radiation-free alternative to fluoroscopic nephrostogram following percutaneous nephrolithotomy.

BACKGROUND: We evaluated the hydrostatic pressure of the renal pelvis (RPP) as a radiation-free alternative to fluoroscopic nephrostogram to assess ureteral patency after percutaneous nephrolithotomy (PCNL). METHODS: Retrospective non-inferiority study analyzing 248 PCNL-patients (86 female (35%) and 162 males (65%)) between 2007 and 2015. Postoperatively, RPP was measured using a central venous pressure manometer in cmH2O. The primary endpoint was to assess RPP depending on the patency of the ureter and the nephrostomy tube removal. Secondary, the upper limit of normal RPP of [Formula: see text] 20 cmH2O was assessed as an indicator of an unobstructed patency. RESULTS: The median procedure duration was 141 min (112-171.5) with a stone free rate of 82% (n = 202). RPP was significantly higher in patients with obstructive nephrostogram with 25.0 mmH2O (21.0-32.0) versus 20.0 mmH2O (16.0-24.0; p < 0.001). The pressure was lower in successful nephrostomy removal with 18 cmH2O (15-21) versus 23 cmH2O (20-29) in the leakage group (p < 0.001). The analysis of a cut-off of [Formula: see text] 20 cmH2O showed a sensitivity of 76.9% (95% CI [60.7%; 88.9%]) and a specificity of 61.5% (95% CI [54.6%; 68.2%]). The negative predictive value was 93.4% (95% CI: [87.9%; 97.0%]) and the positive predictive value 27.3% (95% CI [19.2%; 36.6%]). The accuracy of the model showed an AUC = 0.795 (95% CI [0.668; 0.862]). CONCLUSION: The hydrostatic RPP seems to allow a bedside evaluation of ureteral patency after PCNL.

Sarcomatoid urothelial carcinoma of the renal pelvis treated with immunotherapy.

BACKGROUND: Sarcomatoid carcinoma is a rare, high-grade malignancy with epithelial and mesenchymal components. It may be a good candidate for immunotherapy because it is associated with overexpression of programmed cell death ligand 1. Sarcomatoid urothelial carcinoma (UC) of the upper urinary tract is extremely rare. Here we report the first case of sarcomatoid UC of the renal pelvis that responded to immunotherapy. CASE PRESENTATION: A 79-year-old man was referred to our hospital complaining of various symptoms, including anorexia and abdominal pain. A computed tomography scan revealed a right atrial tumor, a 9 cm left renal mass with a renal vein tumor thrombus, para-aortic lymphadenopathy, and multiple small lung nodules. The patient underwent resection of the right atrial tumor. Pathological analysis of the tumor did not lead to an accurate diagnosis even after several rounds of immunohistochemistry. He underwent a needle biopsy of the left kidney and was initially diagnosed with collecting duct carcinoma, a rare subtype of renal cell carcinoma (RCC). Following the initial diagnosis, immunotherapy with nivolumab and ipilimumab commenced. Thereafter, almost all lesions, including the left renal tumor, were reduced in size. However, he underwent a left nephrectomy approximately a year after beginning immunotherapy due to repeated left renal bleeding. Histological examination of the nephrectomy specimen revealed two forms of cancer-sarcomatoid UC and conventional high-grade UC. Two months after surgery, the patient was found to have new lung metastases. He underwent chemotherapy with gemcitabine and cisplatin, followed by immunotherapy with pembrolizumab. However, both treatments were ineffective. The patient died of cancer 19 months after his first admission. CONCLUSIONS: The presented case of sarcomatoid UC of the renal pelvis that partially responded to immunotherapy suggests that immunotherapy can be a promising treatment for sarcomatoid UC.

Squamous cell carcinoma of the renal pelvis masquerading as xanthogranulomatous pyelonephritis.

We report a rare case of a 56-year-old male with a history of hypertension who initially presented to the emergency department with abdominal pain and was radiologically diagnosed with left xanthogranulomatous pyelonephritis (XGP) in a non-functioning kidney with a staghorn calculus. Pathological evaluation of his kidney revealed squamous cell carcinoma (SCC) of the renal pelvis with invasion into the renal parenchyma. We highlight the presentation, diagnosis, and management of this rare condition.

The renal pelvis urobiome in the unilateral kidney stone patients revealed by 2bRAD-M.

BACKGROUND: The pathogenesis of kidney stone disease (KSD) is not fully understood, and potential contributing factors remain to be explored. Several studies have revealed that the urinary microbiome (urobiome) of stone formers was distinct from that of healthy individuals using 16S rRNA gene sequencing, most of which only provided microbial identification at the genus level. 2bRAD sequencing for Microbiome (2bRAD-M) is a novel sequencing technique that enables accurate characterization of the low-biomass microbiome at the species resolution. We aimed to apply 2bRAD-M to profile the renal pelvis urobiome of unilateral kidney stone patients and compared the urobiome with and without stone(s). METHOD: A total of 30 patients with unilateral stones were recruited, and their renal pelvis urine from both sides was collected. A ureteroscope was inserted into the renal pelvis with stone(s) and a ureteral catheter was placed into the ureteroscope to collect renal pelvis urine. This procedure was repeated again with new devices to collect the urine of the other side. 2bRAD-M was performed to characterize the renal pelvis urobiome of unilateral stone formers to explore whether microbial differences existed between the stone side and the non-stone side. RESULTS: The microbial community composition of the stone side was similar to that of the non-stone side. Paired comparison showed that Corynebacterium was increased and Prevotella and Lactobacillus were decreased in the stone side. Four species (Prevotella bivia, Lactobacillus iners, Corynebacterium aurimucosum, and Pseudomonas sp_286) were overrepresented in the non-stone side. 24 differential taxa were also identified between two groups by linear discriminant analysis effect size (LEfSe). Extensive and close connections among genera and species were observed in the correlation analysis. Moreover, a random forest classifier was constructed using specific enriched species, which can distinguish the stone side from the non-stone side with an accuracy of 71.2%. CONCLUSION: This first 2bRAD-M microbiome survey gave an important hint towards the potential role of urinary dysbiosis in KSD and provided a better understanding of mechanism of stone formation.

Renal pelvis mucosal artery hemorrhage after percutaneous nephrolithotomy: a rare case report and literature review.

BACKGROUND: Following a percutaneous nephrolithotomy (PCNL) procedure, the most common complications are considered to be intraoperative and postoperative bleeding. Many patients with postoperative bleeding can be treated conservatively, causing the perirenal hematoma to resolve spontaneously. The major causes of severe postoperative bleeding are pseudoaneurysms, arteriovenous fistula, and segmental arterial injury. Typically, the first choice of treatment to manage severe bleeding complications is selective angioembolization (SAE) because of the very high success rate associated with this procedure. CASE PRESENTATION: This clinical case involves a 56-year-old man who underwent dual-channel PCNL treatment after diagnosing a left kidney staghorn stone and urinary tract infection. The operation was successful, with no apparent signs of bleeding. Tests revealed continued decreasing hemoglobin levels following the procedure. After the conservative treatment failed, renal angiography was performed immediately, indicating renal pelvis mucosal artery hemorrhage. In the three hours post-surgery, the SAE still failed to prevent bleeding. Further discussions led to formulating a new surgical plan using a nephroscope to enter the initial channel where hemostasis began. The hemostasis origin was found precisely in the mucosal artery next to the channel during the operation and was successfully controlled. CONCLUSIONS: This case reveals there is poor communication and inadequate discussions about the potential failures of an SAE procedure. Swift clinical decision-making is imperative when dealing with high-level renal trauma to prevent delays in surgery that can threaten the safety of patients.