Renal ectopia results from an abnormal arrest of renal ascent during embryonic development and is often associated with malrotation, unusual vasculature, and anomalies of the collecting system. Although numerous ectopic kidneys are asymptomatic and discovered incidentally, their variant anatomy holds clinical significance as it may interfere with imaging interpretation and surgical procedures. We present a case of a right iliac ectopic kidney identified during the routine dissection of an 82-year-old male donor. The kidney was located in the right iliac fossa and demonstrated marked anterior malrotation, a large extrarenal pelvis, a solitary aberrant artery originating from the right common iliac bifurcation and entering the superior pole, venous drainage into the right common iliac vein, and multiple cortical and medullary cysts. The contralateral kidney was situated in its normal position and was grossly unremarkable. This combination of positional, vascular, collecting-system, and parenchymal variations exemplifies the complexity of renal ectopia and underscores the importance of meticulous anatomical identification. Understanding these variants is essential for radiologists, surgeons, and anatomists, as failure to recognize an ectopic kidney may result in diagnostic errors or iatrogenic injury during pelvic and vascular interventions.

Nail-patella syndrome (NPS) is an uncommon autosomal dominant condition marked by nail dysplasia, skeletal abnormalities, and variable renal manifestations, resulting from mutations in the LMX1B gene. We report a rare case of a 23-year-old male presenting with nephrotic-range proteinuria, characteristic skeletal manifestations of NPS, and a family history of renal failure. Genetic testing identified a previously unreported heterozygous missense variant in the homeodomain of LMX1B (c.791A>C; p.Gln264Pro), supporting its pathogenicity. The absence of patellar hypoplasia in our patient highlights the phenotypic variability of NPS. This case reinforces the importance of detailed physical examination and targeted genetic testing in diagnosing nephrotic syndromes.

AXIOS[TM] stents are a new technology being utilized to transform the management of pancreatic fluid collections. Their novel anchoring mechanism intends to diminish unwanted complications such as stent malposition and migration. Though, even with this new mechanism, these remain prominent adverse events. Yet there is insufficient recognition within the literature of such events, as no cases have been reported of uncorrected stent misplacement into an unintended organ. We present a case of an AXIOS[TM] stent that was inadvertently placed into the extrarenal pelvis demonstrating the complexity of procedures when encountering atypical anatomy and the utility of additional imaging for intraprocedural guidance.

To analyze available randomized clinical trials (RCTs) comparing retrograde intrarenal surgery (RIRS) with other modalities for urinary stone treatment to determine the extent of comparing the pelvicalyceal system (PCS) anatomy between patients. In December 2024, a search was conducted in databases and was limited to publications that describe comparisons of experimental and control groups in the context of RIRS for stones only in the kidney (PCS). Only RCTs comparing RIRS with other modalities without publication date restriction were included due to their highest level of evidence in the hierarchy of primary research. The parameters used in the selected studies were analyzed to compare the differences between the groups, focusing on PCS anatomy. The final analysis included 27 publications from 2421 articles. The presence and/or degree of hydronephrosis were analyzed in 8 studies. Direct morphometric measurements were compared in 4 studies and were focused on the lower pole only, namely the infundibulopelvic angle, infundibular length, and infundibular width. Features such as the position of the renal pelvis in relation to the kidney parenchyma (intrarenal, extrarenal), number and orientation of calyces, as well as the existing PCS classifications were not compared or used. This review shows gaps in the literature while assessing and reporting on PCS anatomy in studies with RIRS. Unless studies mention these anatomical factors without excluding certain groups of patients, it is difficult to compare outcomes between modalities and in between studies.

BACKGROUND Insertion of a ureteric double-J stent is the main treatment for obstruction of the ureter when conservative treatment fails, but stent migration is a recognized complication. This report presents the case of a 54-year-old woman with a history of left upper-ureteric calculus, and hydronephrosis managed with holmium laser lithotripsy and insertion of a double-J stent, who presented with extra-renal stent migration. CASE REPORT A 54-year-old woman was hospitalized 1 day after onset of left low back pain and diagnosed with left upper-ureteral calculi with hydronephrosis and urinary tract infection. After anti-infection treatment, ureteroscopic holmium laser lithotripsy was performed and ureteral stents were implanted along zebra guide wires. However, intraoperative ureteroscopy of the bladder, ureter, and renal pelvis did not reveal ureteral stents. Bedside X-ray examination and routine computed tomography (CT) examination confirmed complete ectopic extra-renal placement of the double-J stent. A normal ureteral stent was removed 4 weeks after surgery, and a double-J stent was removed laparoscopically outside the kidney. During the operation, there was mild adhesion around the ectopic double-J stent. After removing the ureteral stent, the patient recovered well and was discharged. CONCLUSIONS This report highlights the importance of patient follow-up after inserting a ureteral stent, as stent migration can be an early or late complication.

Müllerian anomalies (MA) occur as a result of errors during embryogenesis. These changes are associated with genetic mutations, developmental disabilities, or environmental causes that affect the embryonic development stages. This paper describes a rare case report of a 22-year-old female who came to our hospital due to dyspareunia after one year of evolution. A thorough history, physical examination, and imaging studies led to the diagnosis of a complete septate uterus with septate cervix and longitudinal vaginal septum. Abdominal computed tomography diagnosed the left extrarenal pelvis. Hysteroscopic resection of the uterine septum and vaginal septoplasty were performed without any complications. Dyspareunia improved at the six-month follow-up. The description of this case is to share our experience and contribute to all common uncommon cases of MA reports.

Around 180 genes have been associated with congenital anomalies of the kidney and urinary tract (CAKUT) in mice, and represent promising novel candidate genes for human CAKUT. In whole-exome sequencing data of two siblings with genetically unresolved multicystic dysplastic kidneys (MCDK), prioritizing variants in murine CAKUT-associated genes yielded a rare variant in the teashirt zinc finger homeobox 3 (TSHZ3) gene. Therefore, the role of TSHZ3 in human CAKUT was assessed. Twelve CAKUT patients from 9/301 (3%) families carried five different rare heterozygous TSHZ3 missense variants predicted to be deleterious. CAKUT patients with versus without TSHZ3 variants were more likely to present with hydronephrosis, hydroureter, ureteropelvic junction obstruction, MCDK, and with genital anomalies, developmental delay, overlapping with the previously described phenotypes in Tshz3-mutant mice and patients with heterozygous 19q12-q13.11 deletions encompassing the TSHZ3 locus. Comparable with Tshz3-mutant mice, the smooth muscle layer was disorganized in the renal pelvis and thinner in the proximal ureter of the nephrectomy specimen of a TSHZ3 variant carrier compared to controls. TSHZ3 was expressed in the human fetal kidney, and strongly at embryonic day 11.5-14.5 in mesenchymal compartments of the murine ureter, kidney, and bladder. TSHZ3 variants in a 5' region were more frequent in CAKUT patients than in gnomAD samples (p < 0.001). Mutant TSHZ3 harboring N-terminal variants showed significantly altered SOX9 and/or myocardin binding, possibly adversely affecting smooth muscle differentiation. Our results provide evidence that heterozygous TSHZ3 variants are associated with human CAKUT, particularly MCDK, hydronephrosis, and hydroureter, and, inconsistently, with specific extrarenal features, including genital anomalies.

Extrarenal rhabdoid tumors (ERRTs) are highly aggressive pediatric tumors with very few cases reported in the literature. These tumors, similar to their renal counterparts, are characterized by inactivating mutations of the SMARCB1/INI-1 gene, a member of the SWI/SNF chromatin remodeling pathway. Diagnosis of ERRTs appears challenging owing to its rarity, varied morphological profile with a higher tendency for rhabdoid differentiation, and overlapping features with other SMARCB-1 deficient tumors. Here, we report a case of ERRT in the pelvis of a three-year-old child with an unusual expression of SALL4 and C-kit on immunohistochemistry. A complete immunohistochemical workup might help in differentiating ERRTs from other SMARCB1/INI1-deficient soft tissue tumors. The expression of stem cell markers in the presented case also suggests that these tumors might originate from or share similarities with embryonic stem cells or germ cells.

Kidney cysts in humans are mainly caused by inheritable polycystic kidney disease. Although they are a regular finding in laboratory mice, their occurrence upon dissection has not been systematically investigated, yet. Therefore, the aim of this report was to investigate on prevalence, phenotype and aetiology of spontaneously occurring kidney cysts in mice by retrospectively analysing the laboratory-receipt tables of the in-house laboratory of a central animal facility in North Rhine-Westphalia, Germany, years 2009-2019. A percentage of 0.4% of dissected mice displayed kidney cysts, with more male than female animals affected and average age equal to that of all dissected animals. Preliminary report in half of the cases was distended abdomen, and a few individuals displayed additional pathologic alterations of kidneys, most commonly dilated renal pelvis, or extrarenal comorbidities. Kidney cysts occurred independently of a renal phenotype of the transgenic strain or presence of infectious agents in health monitoring. To conclude, kidney cysts were characterized as harmless for affected mice but, as inheritability is suggested according with the literature, affected animals should be excluded from breeding.

We report a case of a 57 years old woman with a solitary mass located in the pelvis diagnosed as an extrarenal papillary renal cell carcinoma, in the absence of a primary renal cancer. The diagnosis was based on cytomorphological features and further confirmed by immunochemistry findings following surgical excision. The hypothesis of a tumor developing in a supernumerary or ectopic kidney was excluded, since no normal renal tissue could be identified in the specimen and in the preoperative computed tomography and MRI images.

Myelolipoma of the kidney is an exceedingly unusual benign tumor of hematological components mixed with mature adipose tissue. We present a case of a 59-year-old male who presented with left flank pain and was found to have an atrophic left kidney on imaging studies. A computed tomography (CT) scan revealed a small and shrunken left kidney with an extrarenal pelvis. A diethylenetriamine pentaacetate (DTPA) scan results showed a total glomerular filtration rate (GFR) of 45.6 ml/min with a non-functional left kidney. The patient underwent a left nephrectomy, and a histopathological examination confirmed the diagnosis and highlighted the distinctive morphological features of this rare entity. Postoperatively, the patient experienced a complete resolution of symptoms. This case underscores the importance of considering myelolipoma in the differential diagnosis of renal masses and highlights the successful management of symptomatic cases through surgical intervention. Awareness of this rare tumor is crucial for accurate diagnosis and appropriate management. Further studies are needed to elucidate the natural history and optimal treatment strategies for renal myelolipomas.