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Background: Nephrocalcinosis (NC) is characterized by an excessive accumulation of calcium deposits in the kidneys. In children, it is often incidentally discovered with an uncertain prognosis. Case-diagnosis/treatment: A 3-month-old girl suspected to have a milk protein allergy underwent an ultrasound that revealed increased echogenicity in the kidney pyramids suggestive of medullary NC. At the age of 18 months, imaging findings revealed not only hyperechogenicity in the medulla but also in the cortex. Over the course of a long follow-up, her kidneys maintained size within the upper limits but showed an increase by age 7. Genetic analysis identified PKHD1 variants, which required structural predictive tools to guide clinical diagnosis. Until the age of 7, her kidney function has remained intact; however, her prognosis is uncertain. Conclusions: NC in newborns is a rare condition, but its incidence is rising. Recurrent urinary infections or kidney stones may lead to kidney failure. A proactive approach in sporadic NC enables an early diagnosis to orientate clinical supervision and facilitates counseling to support family planning decisions. [ABSTRACT FROM AUTHOR]

Objective: To assess the impact of kidney stone disease (KSD) and its treatment on the health‐related quality of life (HRQOL) of high‐risk stone formers with hyperparathyroidism, renal tubular acidosis, malabsorptive disease, and medullary sponge kidney. Patients and Methods: The Wisconsin Stone Quality of Life questionnaire was used to evaluate HRQOL in 3301 patients with a history of KSD from 16 institutions in North America between 2014 and 2020. Baseline characteristics and medical history were collected from patients, while active KSD was confirmed through radiological imaging. The high‐risk group was compared to the remaining patients (control group) using the Wilcoxon rank‐sum test. Results: Of 1499 patients with active KSD included in the study, the high‐risk group included 120 patients. The high‐risk group had significantly lower HRQOL scores compared to the control group (P < 0.01). In the multivariable analyses, medullary sponge kidney disease and renal tubular acidosis were independent predictors of poorer HRQOL, while alkali therapy was an independent predictor of better HRQOL (all P < 0.01). Conclusions: Among patients with active KSD, high‐risk stone formers had impaired HRQOL with medullary sponge kidney disease and renal tubular acidosis being independent predictors of poorer HRQOL. Clinicians should seek to identify these patients earlier as they would benefit from prompt treatment and prevention. [ABSTRACT FROM AUTHOR]

A 51-year-old male with a history of Cacchi-Ricci disease and long-standing infection with various species of Borrelia, Babesia, and Bartonella presented with recurrent symptoms of right-sided flank pain. Numerous renal calculi were identified on imaging. The etiology of the calculi had not been previously elucidated. Symptoms intermittently date back to 2002 when uric acid stones were identified. Subsequent calculi analysis revealed calcium oxalate stones. Despite the commonality of nephrolithiasis in patients with Cacchi-Ricci disease, the extreme number of calculi and recurrent presentation of symptoms persisted despite a plethora of medical evaluations, dietary changes, and hereditary testing. This case raises questions of etiology including possible immune deficiency and whether his uncommon microbial history contributes to recurrent stone formation. [ABSTRACT FROM AUTHOR]

Medullary sponge kidney or Cacchi Ricci disease is a malformation that affects the distal nephron, characterized by the dilation of the medullary and papillary portions of the collecting ducts. The majority of cases are sporadic, with dominant autonomic inheritance in only 5%1. The clinical picture and prognosis are usually indolent, however, it may be associated with urinary tract infections, nephrolithiasis and, less frequently, hematuria and low back pain. We present below the case of a patient with persistent macrohematuria of 9 years of evolution, with multiple inconclusive studies during those years, with a final diagnosis of medullary sponge kidney. [ABSTRACT FROM AUTHOR]

A 51-year-old male with a history of Cacchi-Ricci disease and long-standing infection with various species of Borrelia, Babesia, and Bartonella presented with recurrent symptoms of right-sided flank pain. Numerous renal calculi were identified on imaging. The etiology of the calculi had not been previously elucidated. Symptoms intermittently date back to 2002 when uric acid stones were identified. Subsequent calculi analysis revealed calcium oxalate stones. Despite the commonality of nephrolithiasis in patients with Cacchi-Ricci disease, the extreme number of calculi and recurrent presentation of symptoms persisted despite a plethora of medical evaluations, dietary changes, and hereditary testing. This case raises questions of etiology including possible immune deficiency and whether his uncommon microbial history contributes to recurrent stone formation.

Our paper presents the ultrasound (US) patterns of a rare kidney disease—medullary sponge kidney (MSK)—that have not been described before in comparison with other causes of medullary hyperechogenicity and correlates them with the severity of the disease and prognosis. This is a clinical observational study of all US examinations in the Nephrology Department over a period of 6 years. The abdominal US focused on the kidneys was recorded. US characteristics of the medulla and cortex were analyzed. We found 10 patients with characteristic daisy flower (DF) kidneys. Positive diagnosis in association with other renal risk factors, prognosis, and evolution were evaluated. Two patterns of medullary hyperechogenicity were found and were correlated with disease severity and kidney function. The first pattern is a homogenous echogenicity of the medulla described as a "daisy-like" appearance. The second pattern: calcifications associated with medullar echogenicity, stone production, nephrocalcinosis, and impaired kidney function: "atypical daisy-like." Medullary hyperechogenicity can have more US patterns. In MSK, if the medullary echogenicity is homogenous the evolution is benign, whereas the second, inhomogeneous pattern, has a variable clinical presentation with nephrocalcinosis and the outcome is more severe, leading to chronic kidney disease and impairing the quality of life. [ABSTRACT FROM AUTHOR]

Abstract Background Medullary sponge kidney is generally considered a benign condition, gold standard for the diagnosis is urography but it has almost been replaced by UroCT that did not present the same sensibility. Although it is really rare, our sonography’s findings were consistent with medullary sponge kidney in the transplanted kidneys. Case presentation A 45-year-old woman with a long history of double-kidney transplantation complained of frequent urinary tract infections, a history of vague loin pain and came to our attention for sonography follow-up. Her kidney function was normal, we did not find signs of infections in the transplanted kidneys and urinary findings were normal. Curiously, the transplanted kidneys came from a newborn and the patient received a double-kidney transplantation in order to guarantee a satisfactory renal function. Conclusions Despite a long history of kidney transplantation, genetic disease should not be forgotten when symptoms and images recall to specific inherited alterations. Sonography has to be considered in diagnostic path of kidney cystic disease.

Amyloidosis is a large group of diseases that occur through misfolding of extracellular proteins that accumulate in tissues and organs. Gout is the most common inflammatory arthritis worldwide and starts with the crystallization of uric acid within the joints and soft tissues. Although gouty arthritis is accompanied by inflammation, AA amyloidosis is rarely seen in patients with gout. Here we present a case of AA amyloidosis on the medullary sponge kidney in a 28‐year‐old man with gout. Our case had been diagnosed with gout 3 years previously, and his older brother was also diagnosed with early‐onset gout. As a result of the hyperuricemic nephropathy clinic and familial history, a whole gene sequence analysis was performed on the HPRT1 gene and UMOD gene, but no pathogenic changes were detected. Renal ultrasound revealed a bilateral medullary sponge kidney and amyloidosis was detected in the renal needle biopsy performed for the etiology of proteinuria. In our literature review, we found 16 cases in which gout was accompanied by AA amyloidosis. We present a 17th case and compare it with the other 16 cases. [ABSTRACT FROM AUTHOR]

Background: Medullary sponge kidney (MSK) disease is a rare and neglected congenital condition typically associated with nephrocalcinosis/nephrolithiasis, urinary concentration defects, and cystic anomalies in the precalyceal ducts that, although sporadic in the general population, is relatively frequent in renal stone formers. The physiopathologic mechanism associated with this disease is not fully understood, and omics technologies may help address this gap. Summary: The aim of this review was to provide an overview of the current state of the application of proteomics in the study of this rare disease. In particular, we focused on the results of our recent Italian collaborative studies that, analyzing the MSK whole and extracellular vesicle urinary content by mass spectrometry, have displayed the existence of a large and multifactorial MSK-associated biological machinery and identified some main regulatory biological elements able to discriminate patients affected by this rare disorder from those with idiopathic calcium nephrolithiasis and autosomal dominant polycystic kidney disease (including laminin subunit alpha 2, ficolin 1, mannan-binding lectin serine protease 2, complement component 4-binding protein β, sphingomyelin, ephrins). Key Messages: The application of omics technologies has provided new insights into the comprehension of the physiopathology of the MSK disease and identified novel potential diagnostic biomarkers that may replace in future expensive and invasive radiological tests (including CT) and select novel therapeutic targets potentially employable, whether validated in a large cohort of patients, in the daily clinical practice. [ABSTRACT FROM AUTHOR]

Background: Medullary sponge kidney is generally considered a benign condition, gold standard for the diagnosis is urography but it has almost been replaced by UroCT that did not present the same sensibility. Although it is really rare, our sonography's findings were consistent with medullary sponge kidney in the transplanted kidneys. Case presentation: A 45-year-old woman with a long history of double-kidney transplantation complained of frequent urinary tract infections, a history of vague loin pain and came to our attention for sonography follow-up. Her kidney function was normal, we did not find signs of infections in the transplanted kidneys and urinary findings were normal. Curiously, the transplanted kidneys came from a newborn and the patient received a double-kidney transplantation in order to guarantee a satisfactory renal function. Conclusions: Despite a long history of kidney transplantation, genetic disease should not be forgotten when symptoms and images recall to specific inherited alterations. Sonography has to be considered in diagnostic path of kidney cystic disease. [ABSTRACT FROM AUTHOR]

Medullary sponge kidney (MSK) is an anomaly of the kidney with cystic enlargement of distal tubules generating stasis zones where calcium salt deposits may form and grow locally. From an epidemiological point of view, MSK is reported in 2% to more than 20% of calcium stone formers. The association of stasis and various metabolic disorders explains a high recurrence rate of stones in affected patients. The composition of stones has been poorly investigated. The aim of this study is to compare stone composition and morphology inMSK and non-MSK patients. Material and methods: 1036 stones from MSK patients and 31,494 stones from non-MSK patients were submitted to a morpho-constitutional analysis based on morphological typing under stereo microscope and precise characterization of chemical and crystalline phases by Fourier transform infrared spectroscopy. Results and discussion: Regarding patients, the male to female ratio was significantly lower in MSK vs non-MSK subjects (1.48 vs 2.09, p < 0.00001). The recurrence rate was significantly higher in MSK patients (85.0% vs 39.5% in non-MSK, p < 0.000001). Stones weremore often spontaneously passed in MSK vs non-MSK subjects (45.7% vs 34.6%, p < 0.000001). Stones were mainly composed of calcium oxalate in both groups (66.3% vs 72.5%). However, the slight decrease in the occurrence of calcium oxalate stones was mainly supported by weddellite calculi, less frequent in MSK (17.0% vs 21.6% in non-MSK, p < 0.001). The main point was the high proportion of stones mainly composed of calcium phosphates: 28.9% inMSK vs 13.9% in non-MSK patients) with a high proportion of stones exhibiting a IVa2 morphology which is a marker for distal tubular acidification defect (12.1% in MSK vs 0.4% in non-MSK patients, p < 0.000001). Finally, while stones nucleated from a papillary Randall's plaque were found with a similar frequency in both groups, calcium phosphate nucleus was significantly more frequent in MSK than in non-MSK stones (68.8% vs 48.9%, p < 0.000001), suggesting a frequent initiation of stones from calcium phosphate plugs in distal tubules ectasias. [ABSTRACT FROM AUTHOR]

Medullary sponge kidney (MSK) is an uncommon kidney malformation, characterized by cystic dilatation of the precalyceal papillary collecting ducts. Urography and computed tomography scan represent the gold standard to detect this congenital disorder. A clear diagnosis is not always feasible, especially in the presence of a concomitant renal mass, which in turn can be difficult to detect in MSK patients. When conventional imaging is inconclusive, a renal biopsy can be considered in doubtful cases. Here, we report a unique case of a Bellini duct carcinoma in a patient with MSK and we review the literature on this complex condition., Competing Interests: Disclosure The authors have stated that they have no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Medullary sponge kidney (MSK) is an anomaly of the kidney with cystic enlargement of distal tubules generating stasis zones where calcium salt deposits may form and grow locally. From an epidemiological point of view, MSK is reported in 2% to more than 20% of calcium stone formers. The association of stasis and various metabolic disorders explains a high recurrence rate of stones in affected patients. The composition of stones has been poorly investigated. The aim of this study is to compare stone composition and morphology in MSK and non-MSK patients.Material and methods: 1036 stones from MSK patients and 31,494 stones from non-MSK patients were submitted to a morpho-constitutional analysis based on morphological typing under stereo microscope and precise characterization of chemical and crystalline phases by Fourier transform infrared spectroscopy.Results and discussion: Regarding patients, the male to female ratio was significantly lower in MSK vs non-MSK subjects (1.48 vs 2.09, $p

Medullary sponge kidney (renal spongiosis), (MSK) is a rare developmental anomaly of the kidney of unknown cause. It is presumed, that people with a genetic predisposition (

Introduction: The medullary sponge kidney (MSK) is one of the disorders of kidney development which is known by the cystic dilation of pyelocaliceal system and diffuse precalyceal ectasias. One of the usual complications of this disease is stone formation. Case presentation: In this video article, the study showed two sessions of retrograde intrarenal surgery by endoscopic appearance of MSK during laser lithotripsy. Operative time in the first and second sessions was 100 min and 80 min, respectively. At the 3-month follow-up visit, both kidneys were at normal without obvious stone in kidney-ureter-bladder X-ray. Conclusions: In this video, we presented the endoscopic appearance of MSK during laser lithotripsy and the follow-up pyeloscopy.

Abstract Background Medullary sponge kidney (MSK) is a rare disease characterized by cystic dilatation of papillary collecting ducts. Intravenous urography is still considered the gold standard for diagnosis. We identified a cohort of patients from our outpatient clinic with established diagnosis of MSK to outline some ultrasonographic characteristics that may help establish a diagnosis. Methods We conducted a retrospective study of patients seen between January 1st 2009 and January 1st 2019 in our clinic. Out of 4321 patients, 18 had a diagnosis of MSK. We reviewed their clinical and family history, laboratory data and imaging studies. Specifically, we focused on ultrasound imaging. Results Patients were referred to our outpatient clinic because of renal impairment (44%), family history of nephropathy (17%), nephrolithiasis or an established diagnosis of MSK (39%). Seventy-two percent of patients presented with chronic kidney disease, 22% required hemodialysis. Urinary tract infections (44%), nephrolithiasis (33%), microscopic hematuria (50%) and proteinuria (44%) were reported. Seven patients underwent computed tomography; all of them received ultrasound. Ultrasound examination showed bilateral renal cysts, usually small and located in the renal medulla, and microcalcifications located in the medulla or within the cysts. Conclusion We identified a peculiar tetrad associated with MSK: 1) hypoechoic medullary areas, 2) hyperechoic spots, 3) microcystic dilatation of papillary zone, 4) multiple calcifications (linear, small stones or calcified intracystic sediment) in each papilla. The presence of this diagnostic tetrad, added to laboratory data and clinical history, could be helpful in the differential diagnosis to identify patients with MSK.

Medullary sponge kidney (MSK) is a characteristic renal malformation, with a relatively low incidence. Radiologically, identification of MSK is sometimes ambiguous when compared to a renal mass. Here, we report a novel renal clear cell carcinoma in MSK, and discuss our approach to treatment. We recommended that a preoperative biopsy should be performed, followed by a comprehensive discussion regarding the appropriate perioperative preparations and careful surgical techniques that should be performed for this complex disease.

Background: Molecular biology has recently added new insights into the comprehension of the physiopathology of the medullary sponge kidney disease (MSK), a rare kidney malformation featuring nephrocalcinosis and recurrent renal stones. Pathogenesis and metabolic alterations associated to this disorder have been only partially elucidated.Methods: Plasma and urine samples were collected from 15 MSK patients and 15 controls affected by idiopathic calcium nephrolithiasis (ICN). Plasma metabolomic profile of 7 MSK and 8 ICN patients was performed by liquid chromatography combined with electrospray ionization tandem mass spectrometry (UHPLC–ESI-MS/MS). Subsequently, we reinterrogated proteomic raw data previously obtained from urinary microvesicles of MSK and ICN focusing on proteins associated with sphingomyelin metabolism. Omics results were validated by ELISA in the entire patients' cohort.Results: Thirteen metabolites were able to discriminate MSK from ICN (7 increased and 6 decreased in MSK vs. ICN). Sphingomyelin reached the top level of discrimination between the two study groups (FC: −1.8, p < 0.001). Ectonucleotide pyrophophatase phosphodiesterase 6 (ENPP6) and osteopontin (SPP1) resulted the most significant deregulated urinary proteins in MSK vs. ICN (p < 0.001). ENPP6 resulted up-regulated also in plasma of MSK by ELISA.Conclusion: Our data revealed a specific high-throughput metabolomics signature of MSK and indicated a pivotal biological role of sphingomyelin in this disease.

Background: Medullary sponge kidney (MSK) disease predisposes patients to recurrent nephrolithiasis, which affects one in every 5000 people in the United States. Methods: We report a rare case of a pediatric recipient of a living donor MSK transplant and discuss considerations when discussing risks and benefits of accepting MSK allografts for this population. Results: The recipient was admitted due to concerns for nephrolithiasis, hydronephrosis, and urinary tract infection at 1‐month post‐transplant. The hydronephrosis was resolved by surgical removal of an encrusted ureteral stent; this was followed by supplementation with oral medications to prevent future episodes of nephrolithiasis. The recipient did not have any further episodes after this as seen at a 1‐year follow‐up. The donor has remained well through this period. Conclusions: With increasing organ shortages, the use of variety of donors may need to be considered to enlarge the organ pool. [ABSTRACT FROM AUTHOR]

Abstract Background Medullary sponge kidney is a rare renal malformation, which usually manifests as nephrocalcinosis, renal tubular acidosis, and recurrent urinary tract infections. Medullary sponge kidney is often associated with renal developmental anomalies and tumors, and its exact pathogenesis is not yet clearly explained. Given the key role of the interaction of glial cell line-derived neurotrophic factor gene, GDNF, and the “rearranged during transfection” proto-oncogene, RET, in kidney and urinary tract development, variations in these genes are proposed to be candidates for medullary sponge kidney. Hyperparathyroidism is observed in a few patients with medullary sponge kidney, but the exact pathogenesis of this association is unknown. This case report highlights the coexistence of these two conditions associated with RET polymorphism, which contributes toward the understanding of the pathogenesis of medullary sponge kidney. Case presentation A 52-year-old Chinese woman with recurrent renal stones presented to our hospital. Subsequently she was diagnosed as having medullary sponge kidney and tertiary hyperparathyroidism and underwent parathyroidectomy. Genomic DNA was isolated from lymphocytes and the GDNF and RET genes were determined by Sanger sequencing. Two RET polymorphisms were found in our patient, one was nonsynonymous c.2071G>A (G691S; rs1799939) located in exon 11, the other was synonymous c.2712C>G. (p.S904S; rs1800863) located in exon 15. Conclusions We demonstrated a case of medullary sponge kidney combined with tertiary hyperparathyroidism, which contributes to further understanding of the pathogenesis of this disease. Besides, we also found RET G691S/S904S polymorphism in this patient, but additional studies are required to explore the role of the RET gene in medullary sponge kidney with hyperparathyroidism.

Over 1%–15% of the population worldwide is affected by nephrolithiasis, which remains the most common and costly disease that urologists manage today. Identification of at-risk individuals remains a theoretical and technological challenge. The search for monogenic causes of stone disease has been largely unfruitful and a technological challenge; however, several candidate genes have been implicated in the development of nephrolithiasis. In this review, we will review current data on the genetic inheritance of stone disease, as well as investigate the evolving role of genetic analysis and counseling in the management of nephrolithiasis.

Medullary sponge kidney (MSK) is a description of radiographic features. However, the pathogenesis of MSK remains unclear. MSK is supposed to be the cause of secondary distal renal tubular acidosis (dRTA), although there are case reports suggesting that MSK is a complication of primary dRTA. In addition to these reports, we report 3 patients with metabolic acidosis and MSK, in whom primary dRTA is confirmed by molecular genetic analyses of SLC4A1 and ATP6V1B1 genes. With a comprehensive genetics-first approach using the 100,000 Genomes Rare Diseases Project dataset, the association between MSK and primary dRTA is examined. We showed that many patients with MSK phenotypes are genetically tested with a gene panel which does not contain dRTA-associated genes, revealing opportunities for missed genetic diagnosis. Our cases highlight that the radiological description of MSK is not a straightforward disease or clinical phenotype. Therefore, when an MSK appearance is noted, a broader set of causes should be considered including genetic causes of primary dRTA as the underlying reason for medullary imaging abnormalities., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

Chronic pain is a common reason for which people in the USA seek medical care. It is linked to opioid consumption, anxiety and a reduction in quality of life. Over the past 50 years, spinal cord stimulation (SCS) has evolved as a safe and efficacious treatment for chronic pain etiologies. The authors present the first known case of SCS for pain due to medullary sponge kidney disease. This report adds to the growing body of literature supporting the use of SCS for treating visceral organ pain, while also highlighting the utility of ventral lead placement for treating visceral pain. As SCS utilization increases, it is expected that there will be a decrease in opioid consumption, and this will help us contain the opioid epidemic.

Medullary Sponge Kidney (MSK) disease is a rare congenital malformation of the distal nephron where cystic dilatation is appreciable in the collecting ducts and renal papillae. Most cases of the malformation are thought to arise from a malfunction within neurotrophic factor and tyrosine kinase interactions. Presentation and prognosis are usually indolent; however, they include urinary tract infections (UTI), nephrolithiasis and nephrocalcinosis, distal renal tubular acidosis (dRTA) and hypocitraturia. With an insidious and asymptomatic onset, MSK is a difficult renal manifestation to both diagnose and treat. Difficulty diagnosing MSK today arises from clinical settings deviating from the usage of contrast methods when assessing the urogenital tract. Many healthcare standards for kidney disorders center diagnosis around imaging techniques rather than contrast methods. This ultimately leads to a decrease in the total number of confirmed cases of MSK. Though intra-venous urogram (IVU) remains as the current gold standard to diagnose MSK, other methods such as endoscopy and Multi-detector computed tomography (MDCT) are being put into place. Endoscopic examination and renal biopsy may allow definitive diagnosis; however, such invasive methods may be considered excessive. Moving forward, differential diagnoses for MSK can be made more precisely when patients present with other renal manifestations, especially in groups at risk. These groups include patients between the age of 20 and 30, patients with other renal malformations, high sodium diet patients, hyperparathyroid patients, and patients with family history of MSK. Basic treatment is aimed at controlling stone formation by stabilizing urinary pH. Treatment for patients, especially those prone to forming stones, includes the application of potassium citrate compounds, prophylactic water and diet control, surgical intervention or lithotripsy for removal of symptomatic kidney stones. [ABSTRACT FROM AUTHOR]

Medullary sponge kidney (MSK) disease is a rare and neglected kidney condition often associated with nephrocalcinosis/nephrolithiasis and cystic anomalies in the precalyceal ducts. Little is known about the pathogenesis of this disease, so we addressed the knowledge gap using a proteomics approach. The protein content of microvesicles/exosomes isolated from urine of 15 MSK and 15 idiopathic calcium nephrolithiasis (ICN) patients was investigated by mass spectrometry, followed by weighted gene co-expression network analysis, support vector machine (SVM) learning, and partial least squares discriminant analysis (PLS-DA) to select the most discriminative proteins. Proteomic data were verified by ELISA. We identified 2998 proteins in total, 1764 (58.9%) of which were present in both vesicle types in both diseases. Among the MSK samples, only 65 (2.2%) and 137 (4.6%) proteins were exclusively found in the microvesicles and exosomes, respectively. Similarly, among the ICN samples, only 75 (2.5%) and 94 (3.1%) proteins were exclusively found in the microvesicles and exosomes, respectively. SVM learning and PLS-DA revealed a core panel of 20 proteins that distinguished extracellular vesicles representing each clinical condition with an accuracy of 100%. Among them, three exosome proteins involved in the lectin complement pathway maximized the discrimination between MSK and ICN: Ficolin 1, Mannan-binding lectin serine protease 2, and Complement component 4-binding protein β. ELISA confirmed the proteomic results. Our data show that the complement pathway is involved in the MSK, revealing a new range of potential therapeutic targets and early diagnostic biomarkers.

Medullary sponge kidney (MSK) is a congenital renal disorder. Its association with several developmental abnormalities in other organs hints at the likelihood of some shared step(s) in the embryogenesis of the kidney and other organs. It has been suggested that the REarranged during Transfection (RET) proto-oncogene and the Glial cell line-Derived Neurotrophic Factor (GDNF) gene are defective in patients with MSK, and both RET and GDNF are known to have a role in the development of the central nervous system, heart, and craniofacial skeleton. Among a cohort of 143 MSK patients being followed up for nephrolithiasis and chronic kidney disease at our institution, we found six with one or more associated non-renal anomalies: one patient probably has congenital hemihyperplasia and hypertrophic cardiomyopathy with adipose metaplasia and mitral valve prolapse; one has Marfan syndrome; and the other four have novel associations between MSK and nerve and skeleton abnormalities described here for the first time. The discovery of disorders involving the central nervous system, cardiovascular system and craniofacial skeleton in MSK patients supports the hypothesis of a genetic alteration on the RET-GDNF axis having a pivotal role in the pathogenesis of MSK, in a subset of patients at least. MSK seems more and more to be a systemic disease, and the identification of extrarenal developmental defects could be important in arousing the suspicion of MSK in recurrent stone formers. [ABSTRACT FROM AUTHOR]

Rationale: Pheochromocytomas are a group of tumors with high genetic heterogeneity, and the clinical characteristics of rearranged during transfection (RET)-mutated pheochromocytoma with medullary spongiform kidney are rarely studied. The treatment process of 1 patient with bilateral adrenal pheochromocytoma combined with medullary sponge kidney with RET gene mutation in our department was retrospectively analyzed, and the treatment methods for this type of disease were studied and summarized in combination with relevant literature., Patient Concerns: In this case, the patient was found to have bilateral adrenal masses for 8 years due to physical examination, and intermittent dizziness and discomfort for 2 years. Imaging and related laboratory examinations suggest bilateral adrenal giant pheochromocytoma with bilateral medullary sponge kidney. RET gene testing was performed on the patient and his descendant after signing the informed consent form., Diagnoses: The patient was diagnosed with bilateral adrenal pheochromocytoma with a RET proto-oncogene mutation and a bilateral medullary spongy kidney., Intervision and Outcomes: After sufficient perioperative preparation, retroperitoneal laparoscopic bilateral adrenal pheochromocytoma resection was performed by stages. The operation was successful, and hormone replacement therapy was performed after the operation, with regular follow-up. Relevant genetic testing revealed that the c.1900T > C: p.C634R mutation was detected in the patient's RET gene, which was a heterozygous missense mutation, and the mutation was also present in the son of his family. A literature analysis found that pheochromocytoma is a tumor with high genetic heterogeneity, and the RET proto-oncogene is a common pathogenic gene for bilateral adrenal pheochromocytoma. Medullary sponging of kidneys is a rare complication of this disease., Lessons: On the basis of adequate perioperative preparation, surgical resection is the most effective and preferred treatment for this type of disease. Laparoscopic surgery is minimally invasive, safe, and effective by stages. Mutations in the RET proto-oncogene may lead to medullary spongy kidneys in multiple endocrine neoplasia 2., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Patients with medullary sponge kidney (MSK) commonly encounter recurrent nephrolithiasis. The existing knowledge on safety of donors with MSK has not been studied. Methods: We conducted a retrospective cohort study at a tertiary referral hospital to assess the outcomes of living kidney donors with MSK. All adults with MSK (N = 26) who underwent nephrectomy as living kidney donors between January 2000 and September 2014 were included. Non-donors with MSK (N = 78) were randomly selected by matching the year of birth and the comorbidity score with a ratio of 1:3 for comparison. Results: The incident rates of symptomatic stone were 0.7, 0.4 and 4.9 events/100 patient-years in donors, recipients and nondonors, respectively. After adjusting for history of kidney stones and baseline estimated glomerular filtration rate (eGFR), the kidney stone-related event was significantly lower in donors than in non-donors (hazard ratio 0.14; 95% confidence interval 0.01-0.66). One recipient of MSK living donor had symptomatic stone at median follow-up time of 8.4 years (interquartile range 5.6-12.4 years). None of MSK donors had hypercalciuria, hypocitraturia or hyperoxaluria prior to kidney donation. At 5 years after the index surgery date, there was no significant difference in eGFR between donors and non-donors (76.1 versus 70.9 mL/ min/1.73 m2, P = 0.12). Conclusions: These findings are reassuring for the safety of MSK kidney donors with normal kidney function, low kidney stone risk and no significant comorbidity. [ABSTRACT FROM AUTHOR]

Medullary sponge kidney (MSK) is a congenital kidney malformation that is characterized by dilatation of the collecting tubules in the medullary pyramids. Cyst-like areas then form which predispose to nephrocalcinosis, stone formation and recurrent urinary tract infection (UTI). There is an association with defective distal renal tubular acidification and concentration abnormalities such as hypocitraturia. MSK is generally believed to be a sporadic disorder, but an autosomal dominant inheritance is also reported. More recently genetic mutations have been recognised as a possible contributor to the aetiology of the condition. In this article we summarize the available English language literature on the subject of MSK, including its pathogenesis, diagnosis, prognosis and treatment. [ABSTRACT FROM AUTHOR]