Renal Pathology of Ciliopathies

Renal ciliopathies are a group of genetic disorders that affect the function of the primary cilium in the kidney, as well as other organs. Since primary cilia are important for regulation of cell signaling pathways, ciliary dysfunction results in a range of clinical manifestations, including renal failure, cyst formation, and hypertension. We summarize the current understanding of the pathophysiological and pathological features of renal ciliopathies in childhood, including autosomal dominant and recessive polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome, as well as skeletal dysplasia associated renal ciliopathies. The genetic basis of these disorders is now well-established in many cases, with mutations in a large number of cilia-related genes such as PKD1, PKD2, BBS, MKS, and NPHP being responsible for the majority of cases. Renal ciliopathies are broadly characterized by development of interstitial fibrosis and formation of multiple renal cysts which gradually enlarge and replace normal renal tissue, with each condition demonstrating subtle differences in the degree, location, and age-related development of cysts and fibrosis. Presentation varies from prenatal diagnosis of congenital multisystem syndromes to an asymptomatic childhood with development of complications in later adulthood and therefore clinicopathological correlation is important, including increasing use of targeted genetic testing or whole genome sequencing, allowing greater understanding of genetic pathophysiological mechanisms.

First case of nodular dermatofibrosis with cystic renal disease in a beagle: An atypical case without FLCN gene mutation

This report presents the first case of nodular dermatofibrosis with renal cysts (NDRC) in a beagle. In this atypical case, the gene mutation associated with the disease was not present, the renal cysts showed dynamic changes in size and number, and the patient has greatly surpassed the NDRC life expectation.

Ouabain enhances renal cyst growth in a slowly progressive mouse model of autosomal dominant polycystic kidney disease

Renal cyst progression in autosomal dominant polycystic kidney disease (ADPKD) is highly dependent on agents circulating in blood. We have previously shown, using different in vitro models, that one of these agents is the hormone ouabain. By binding to Na+-K+-ATPase (NKA), ouabain triggers a cascade of signal transduction events that enhance ADPKD cyst progression by stimulating cell proliferation, fluid secretion, and dedifferentiation of the renal tubular epithelial cells. Here, we determined the effects of ouabain in vivo. We show that daily administration of ouabain to Pkd1RC/RC ADPKD mice for 1-5 mo, at physiological levels, augmented kidney cyst area and number compared with saline-injected controls. Also, ouabain favored renal fibrosis; however, renal function was not significantly altered as determined by blood urea nitrogen levels. Ouabain did not have a sex preferential effect, with male and female mice being affected equally. By contrast, ouabain had no significant effect on wild-type mice. In addition, the actions of ouabain on Pkd1RC/RC mice were exacerbated when another mutation that increased the affinity of NKA for ouabain was introduced to the mice (Pkd1RC/RCNKAα1OS/OS mice). Altogether, this work highlights the role of ouabain as a procystogenic factor in the development of ADPKD in vivo, that the ouabain affinity site on NKA is critical for this effect, and that circulating ouabain is an epigenetic factor that worsens the ADPKD phenotype.NEW & NOTEWORTHY This work shows that the hormone ouabain enhances the progression of autosomal dominant polycystic kidney disease (ADPKD) in vivo. Ouabain augments the size and number of renal cysts, the kidney weight to body weight ratio, and kidney fibrosis in an ADPKD mouse model. The Na+-K+-ATPase affinity for ouabain plays a critical role in these effects. In addition, these outcomes are independent of the sex of the mice.

CEUS Bosniak Classification-Time for Differentiation and Change in Renal Cyst Surveillance

It is time for a change. CEUS is an established method that should be much more actively included in renal cyst monitoring strategies. This review compares the accuracies, strengths, and weaknesses of CEUS, CECT, and MRI in the classification of renal cysts. In order to avoid overstaging by CEUS, a further differentiation of classes IIF, III, and IV is required. A further development in the refinement of the CEUS-Bosniak classification aims to integrate CEUS more closely into the monitoring of renal cysts and to develop new and complex monitoring algorithms.

Non-suppression of renin by renal cysts in a subset of patients with primary aldosteronism - a prospective observational single centre study

BACKGROUND

Screening for primary aldosteronism is based on measuring aldosterone-to-renin ratio. Non-suppressed renin may cause false negative screening results, and such patients may miss focused, potentially curable treatment. We investigated the association between renal cysts and non-suppressed plasma renin.

METHODS

Altogether 114 consecutive patients with confirmed primary aldosteronism undergoing adrenal vein sampling were prospectively recruited between 7.10.2020 and 30.12.2021. During the procedure, plasma samples for renin analyses were collected from the right and left renal veins and the inferior vena cava. Renal cysts were identified using contrast-enhanced computed tomography.

RESULTS

Renal cysts were found in 58.2% of the 114 patients. Neither screening nor renal vein renin concentrations were significantly different in patients with and without cysts, or when the kidneys with and without cysts were evaluated. However, cysts were significantly more prevalent in the 'high-normal renin' group (cut point 23.0 mU/L) than in the 'low to low-normal renin' group (90.9%, n=11, vs. 56.0%, n=102, P=0.027, respectively). All patients ≤50 years of age in the 'high-normal renin' group had renal cysts. Strong correlations were found between renin concentrations in the right and left renal vein (r=0.984), and between renin concentration and renin activity in the inferior vena cava (r=0.817).

CONCLUSION

Renal cysts are found in the majority of patients with primary aldosteronism, and they may interfere with diagnostics, especially in patients aged 50 years or less. In patients with non-suppressed renin due to renal cysts, aldosterone-to-renin ratio below the diagnostic threshold does not always exclude the diagnosis of primary aldosteronism.

Ciliary ARL13B inhibits developmental kidney cystogenesis in mouse

ARL13B is a small GTPase enriched in cilia. Deletion of Arl13b in mouse kidney results in renal cysts and an associated absence of primary cilia. Similarly, ablation of cilia leads to kidney cysts. To investigate whether ARL13B functions from within cilia to direct kidney development, we examined kidneys of mice expressing an engineered cilia-excluded ARL13B variant, ARL13BV358A. These mice retained renal cilia and developed cystic kidneys. Because ARL13B functions as a guanine nucleotide exchange factor (GEF) for ARL3, we examined kidneys of mice expressing an ARL13B variant that lacks ARL3 GEF activity, ARL13BR79Q. We found normal kidney development with no evidence of cysts in these mice. Taken together, our results show that ARL13B functions within cilia to inhibit renal cystogenesis during mouse development, and that this function does not depend on its role as a GEF for ARL3.

[Features of surgical treatment of renal cysts depending on the risk of malignancy]

BACKGROUND

According to national and foreign publications, renal cyst is one of the most common urological diseases with a prevalence up to 20-50%.

AIM

To determine the results of surgical treatment of patients with renal cysts, depending on the risk of malignancy.

MATERIALS AND METHODS

The analysis of 124 patients with symptomatic renal cysts who were treated in the Department of Urology of Regional Clinical Hospital was carried out. All patients underwent a comprehensive clinical and instrumental evaluation, including contrast-enhanced CT scan of the kidneys. To assess the risk of harboring malignant tumor, the classification of renal cysts of Bosniak (2019) was used.

RESULTS

The average age of patients was 56.6+/-12 years. According to CT, Bosniak I, II, IIF and III cysts were diagnosed in 96 (77.4%), 11 (8.9%), 11 (8.9%) and 6 (4.8%) patients, respectively. The morphologic study revealed renal cell cancer in 8 patients (6.4%), four of whom had Bosniak III cysts and other four had Bosniak IIF cysts.

DISCUSSION

The prediction of the harboring of malignancy is a fundamental criterion for selection of patients with renal cysts for surgical treatment.

CONCLUSION

Surgical treatment of symptomatic renal cysts is a justified treatment method, and in patients with Bosniak class II or higher cysts, it is necessary to exclude the malignant lesion. Based on our data, category IIF and III cysts have a high risk of harboring malignant cells, which is 36.4% and 66.7%, respectively. In our opinion, laparoscopic partial nephrectomy is the most rational treatment method in these categories.

Renal organoid modeling of tuberous sclerosis complex reveals lesion features arise from diverse developmental processes

Tuberous sclerosis complex (TSC) is a multisystem tumor-forming disorder caused by loss of TSC1 or TSC2. Renal manifestations predominately include cysts and angiomyolipomas. Despite a well-described monogenic etiology, the cellular pathogenesis remains elusive. We report a genetically engineered human renal organoid model that recapitulates pleiotropic features of TSC kidney disease in vitro and upon orthotopic xenotransplantation. Time course single-cell RNA sequencing demonstrates that loss of TSC1 or TSC2 affects multiple developmental processes in the renal epithelial, stromal, and glial compartments. First, TSC1 or TSC2 ablation induces transitional upregulation of stromal-associated genes. Second, epithelial cells in the TSC1^-/- and TSC2^-/- organoids exhibit a rapamycin-insensitive epithelial-to-mesenchymal transition. Third, a melanocytic population forms exclusively in TSC1^-/- and TSC2^-/- organoids, branching from MITF⁺ Schwann cell precursors. Together, these results illustrate the pleiotropic developmental consequences of biallelic inactivation of TSC1 or TSC2 and offer insight into TSC kidney lesion pathogenesis.

Characterization of Severity in Zellweger Spectrum Disorder by Clinical Findings: A Scoping Review, Meta-Analysis and Medical Chart Review

Zellweger spectrum disorder (ZSD) is a rare, debilitating genetic disorder of peroxisome biogenesis that affects multiple organ systems and presents with broad clinical heterogeneity. Although severe, intermediate, and mild forms of ZSD have been described, these designations are often arbitrary, presenting difficulty in understanding individual prognosis and treatment effectiveness. The purpose of this study is to conduct a scoping review and meta-analysis of existing literature and a medical chart review to determine if characterization of clinical findings can predict severity in ZSD. Our PubMed search for articles describing severity, clinical findings, and survival in ZSD resulted in 107 studies (representing 307 patients) that were included in the review and meta-analysis. We also collected and analyzed these same parameters from medical records of 136 ZSD individuals from our natural history study. Common clinical findings that were significantly different across severity categories included seizures, hypotonia, reduced mobility, feeding difficulties, renal cysts, adrenal insufficiency, hearing and vision loss, and a shortened lifespan. Our primary data analysis also revealed significant differences across severity categories in failure to thrive, gastroesophageal reflux, bone fractures, global developmental delay, verbal communication difficulties, and cardiac abnormalities. Univariable multinomial logistic modeling analysis of clinical findings and very long chain fatty acid (VLCFA) hexacosanoic acid (C26:0) levels showed that the number of clinical findings present among seizures, abnormal EEG, renal cysts, and cardiac abnormalities, as well as plasma C26:0 fatty acid levels could differentiate severity categories. We report the largest characterization of clinical findings in relation to overall disease severity in ZSD. This information will be useful in determining appropriate outcomes for specific subjects in clinical trials for ZSD.

Improvement of Basal Cell Carcinomas in Patients with Nevoid Basal Cell Carcinoma Syndrome Following by 5-Aminolevulinic Acid Photodynamic Therapy: A Case Report

Nevoid basal cell carcinoma syndrome (NBCCS) is a rare autosomal dominant-inherited disease characterized by multiple basal cell carcinomas, multiple keratocystic odontogenic tumors, palmar and/or plantar pits. A 50-year-old male patient presented to our hospital with multiple plaques and maculopapular lesions on his face and trunk for more than 20 years. A skin biopsy revealed a number of discrete nests of basaloid cells in the dermis where the peripheral cells are arrayed like a palisade. Multiple odontogenic keratocysts and falx cerebri calcification were found. The diagnosis of NBCCS was made. We treated this patient with 5-aminolevulinic acid photodynamic therapy (ALA-PDT) with red light activation, 5% imiquimod cream and surgical excision for the basal cell carcinomas. All the skin lesions on his face improved substantially after eight sessions of red-light ALA-PDT from clinical observation. Red-light ALA-PDT proved to be a good therapeutic method for NBCCS in this case.

AA-amyloidosis in captive northern tree shrews (Tupaia belangeri)

A high prevalence of AA-amyloidosis was identified in a breeding colony of northern tree shrews (Tupaia belangeri) in a retrospective analysis, with amyloid deposits in different organs being found in 26/36 individuals (72%). Amyloid deposits, confirmed by Congo red staining, were detected in kidneys, intestines, skin, and lymph nodes, characteristic of systemic amyloidosis. Immunohistochemically, the deposited amyloid was intensely positive with anti-AA-antibody (clone mc4), suggesting AA-amyloidosis. The kidneys were predominantly affected (80%), where amyloid deposits ranged from mild to severe and was predominantly located in the renal medulla. In addition, many kidneys contained numerous cysts with atrophy of the renal parenchyma. There was no significant association between concurrent neoplastic or inflammatory processes and amyloidosis. The lack of distinctive predisposing factors suggests a general susceptibility of captive T. belangeri to develop amyloidosis. Clinical and laboratory findings of a female individual with pronounced kidney alterations were indicative of renal failure. The observed tissue tropism with pronounced kidney alterations, corresponding renal dysfunction, and an overall high prevalence suggests amyloidosis as an important disease in captive tree shrews.

Renal and Lung Cysts in Birt-Hogg-Dubé Syndrome: A Continuum of the Same Disorder

Birt-Hogg-Dubé (BHD) syndrome is a rare autosomal-dominant disorder, affecting multiple organs, mostly the skin, lungs, and kidneys. The prevalence of BHD syndrome is difficult to define given the rarity of the disease. Patients present most often with primary spontaneous pneumothorax. Renal tumors are a characteristic finding in BHD, and are often bilateral and multifocal and of the chromophobe and oncocytoma variant. Very scarce reports have highlighted the presence of simple renal cysts, as the only phenotypical renal manifestation, in BHD patients. Herein, we highlight two novel cases of bilateral multiple renal and pelvic cysts, in two females with genetically proven BHD syndrome, doubting a potential association with BHD syndrome.

Renal cystic disease in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is associated with TSC1 or TSC2 gene mutations resulting in hyperactivation of the mTORC1 pathway. This mTORC1 activation is associated with abnormal tissue development and proliferation such that in the kidney there are both solid tumors and cystic lesions. This review summarizes recent advances in tuberous sclerosis complex nephrology and focuses on the genetics and cell biology of tuberous sclerosis complex renal disease, highlighting a role of extracellular vesicles and the innate immune system in disease pathogenesis.

Crizotinib-associated renal cyst development may be associated with prolonged progression-free survival in patients with ALK-positive non-small-cell lung cancer: Case report and review of the literature

Non-small cell lung cancer patients with anaplastic lymphoma kinase or c-ros oncogene 1 mutations who are treated with the tyrosine kinase inhibitor crizotinib rarely develop crizotinib-associated renal cysts (CARCs). Here, we present a case report and review of the literature supporting the hypothesis that CARCs may correlate positively with progression-free survival.

A case of TSC2-PKD1 contiguous deletion syndrome: Clinical features and effective treatment for epilepsy

Polycystic kidney disease with Tuberous sclerosis is a disease caused by the deletions of the TSC2-PKD1 gene. The disease is rarely reported and the characterized manifestation is severe polycystic kidney growth. The diagnosis can be made by molecular analysis. We report the first case of PKDTS discovered in infancy in China with typical neurological and renal manifestations. The patient has infantile spasm, polycystic kidney, skin damage, hypertension, and hematuria after infection. After effective treatment of Rapamycin, the seizures were completely controlled. There was not been any renal function damage in the patient. At the same time, we review the related literature and further elaborate on the variety of clinical manifestations, treatment, and prognosis.

Multi-disciplinary team conference clarifies bosniak classification of complex renal cysts

OBJECTIVES

The aims of this study are to determine the progression rate of Bosniak IIF cysts, the malignancy rates of complex renal cysts in patients undergoing surgery and explore the influence of multi-disciplinary team conference (MDT) on re-classification of Bosniak cysts.

MATERIALS AND METHODS

All CT scans from January 2010 to 2017 were pooled into a database. Initially, 167 patients were identified with possible Bosniak IIF, III or IV cysts. Patients with follow up of less than 24 months, without progression or regression were excluded.

RESULTS

Thirty-one (18.6%) cysts of the initial 167 cysts were either up or downgraded at a MDT. Twenty-six of the 31 cysts were up or downgraded at the primary MDT, 13 cysts (50%) were downgraded, five cysts (19.2%) were upgraded and eight cysts (30.8%) were re-classified as solid tumors. Of those 19/26 (73.1%) were primary interpreted by a periphery radiologist and re-classified centrally. The last five patients 5/120 cysts (4.2%) were re-classified during follow up. 116 patients with a total of 120 cysts met the inclusion criteria, 79 (65.8%) Bosniak IIF, 28 (23.3%) Bosniak III and 13 (10.8%) Bosniak IV cysts represented. Median follow up of Bosniak IIF cysts were 46 months. One Bosniak IIF cyst progressed to a solid tumor at 15 months from diagnosis, progression rate 1.3%. Histopathology was papillary renal cell carcinoma. Malignancy rates of Bosniak III and IV cysts were 50% and 78%, respectively.

CONCLUSION

Multi-disciplinary team conference may have an important role in correct classification of Bosniak cysts.

TRIAL REGISTRATION

None.

Contrast-Enhanced Ultrasound (CEUS) for the Evaluation of Bosniak III Complex Renal Cystic Lesions-A 10-Year Specialized European Single-Center Experience with Histopathological Validation

Background and objectives: The aim of the present retrospective single-center study is to evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) for assessing Bosniak III complex renal cystic lesions with histopathological validation. Materials and Methods: 49 patients with CEUS-categorized Bosniak III renal cystic lesions were included in this retrospective study. All patients underwent native B-mode, Color Doppler, contrast-enhanced ultrasound (CEUS) between 2010-2020. Eight and five patients underwent computed tomography (CT) and magnetic resonance imaging (MRI), respectively. Twenty-nine underwent (partial) nephrectomy allowing for histopathological analysis. The applied contrast agent for CEUS was a second-generation blood pool agent. Ultrasonography examinations were performed and interpreted by a single experienced radiologist with more than 15 years of experience (EFSUMB Level 3). Results: CEUS examinations were successfully performed in all included patients without registering any adverse effects. The malignancy rate of CEUS-categorized Bosniak III renal lesions accounted for 66%. Initially, cystic complexity was visualized in native B-mode. In none of the renal lesions hypervascularization was detected in Color Doppler. CEUS allowed for detection of contrast enhancement patterns in all included Bosniak III renal lesions. Delayed wash-out could be detected in 6/29 renal lesions. In two cases of histopathologically confirmed clear-cell RCC, appropriate up-grading from Bosniak IIF to III was achieved by CEUS. Conclusions: CEUS depicts a promising imaging modality for the precise diagnostic workup and stratification of renal cystic lesions according to the Bosniak classification system, thereby helping guidance of adequate clinical management in the future.

Cyst Reduction by Melatonin in a Novel Drosophila Model of Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) causes progressive cystic degeneration of the renal tubules, the nephrons, eventually severely compromising kidney function. ADPKD is incurable, with half of the patients eventually needing renal replacement. Treatments for ADPKD patients are limited and new effective therapeutics are needed. Melatonin, a central metabolic regulator conserved across all life kingdoms, exhibits oncostatic and oncoprotective activity and no detected toxicity. Here, we used the Bicaudal C (BicC) Drosophila model of polycystic kidney disease to test the cyst-reducing potential of melatonin. Significant cyst reduction was found in the renal (Malpighian) tubules upon melatonin administration and suggest mechanistic sophistication. Similar to vertebrate PKD, the BicC fly PKD model responds to the antiproliferative drugs rapamycin and mimics of the second mitochondria-derived activator of caspases (Smac). Melatonin appears to be a new cyst-reducing molecule with attractive properties as a potential candidate for PKD treatment.

Sonographic assessment of kidneys in patients with hypertension co-existed with diabetes mellitus and ischemic heart disease

Background

Hypertension is one of the major world health problems. Ultrasonography plays a useful role in the assessment of morphologicalchanges at the kidneys in hypertensive patients.

Aim

To assess sonographic findings of the kidneys in hypertensive patients' co-morbidities with type 2 diabetes mellitus and ischemic heart disease (IDH).

Materials and Methods

This was a prospective cross-sectional study involved 100 participants with primary hypertension selected by a method of simple convenient sampling. The patients were examined using ultrasonography to assess the sonographic findings of the kidneys. The renal length, corticomedullary differentiation (CMD), and renal artery diameters were assessed. Statistical Package for the Social Sciences (SPSS version 23.0) was used in data analysis.

Results

The length of the right kidney was 8.9850 ± 1.01 cm and 9.48 ± 0.98 cm for the left kidney. Among the hypertensive patients, the incidence of hypertension was highest in housewives (27%) and students (23%) as compared with the other groups. The sonographic findings were 18% affected with simple renal cysts, 7% poor CMD, and the majority had normal kidneys. Significant correlation was found between age and sonographic findings of kidneys (r = 0.21, P value = 0.033).

Conclusion

Simple renal cysts, poor CMD, and stenosis of renal arteries were most common sonographic findings in hypertension. Simple renal cystshad a significant association with hypertension.

Alectinib Induced Regression of Renal and Hepatic Cysts Caused by Crizotinib

Background

Crizotinib is the first tyrosine kinase inhibitor approved for the treatment of anaplastic lymphoma kinase (ALK) rearranged non-small cell lung cancer (NSCLC). An increased incidence of renal cysts has been described during the crizotinib treatment.

Case Presentation

We herein report the case of a 74-year-old woman who received crizotinib for metastatic ALK-positive NSCLC. During the crizotinib treatment, complex renal cystic lesions with invasion of perirenal spaces and iliopsoas muscle appeared; two complex hepatic cysts were also observed. Almost all lesions disappeared after switching to alectinib, a second-generation ALK inhibitor.

Conclusion

It would seem that alectinib is able to reduce in size and number hepatic and renal cysts caused by the crizotinib treatment. Nevertheless, further studies are needed to clarify the role of both crizotinib in the onset of renal and hepatic cysts and alectinib in their disappearance.

Laparoscopic or Robotic Deroofing Guided by Indocyanine Green Fluorescence and Perirenal Fat Tissue Wadding Technique of Pediatric Simple Renal Cysts

Purpose: To present the outcomes of the laparoscopic and robotic treatment of pediatric simple renal cysts with two novel modifications: the indocyanine green (ICG) fluorescence and the perirenal fat tissue wadding technique. Methods: Between 2012 and 2019, 13 patients with solitary renal cysts were treated through minimally invasive approach. Preoperative work-up included ultrasonography and computed tomography or magnetic resonance. A cyst deroofing was performed in all cases. In the last 3 cases, the ICG fluorescence technique enabled a clear identification and safe puncture of the cyst dome. Five cysts were filled with perirenal fat tissue after deroofing. Results: Thirteen patients (9 boys) were treated through laparoscopic (6 patients), retroperitoneoscopic (3 patients), or robotic approach (4 patients). Median age was 8 years (5-15 years). The median cyst size was 70 mm (42-160 mm). Eight cysts were located in the right kidney. All cysts were progressive and symptomatic. Thirteen cysts (100%) were graded as type II according to the Bosniak classification. No conversion was recorded. The median operative time for laparoscopy was 50 minutes (35-90 minutes) and 85 minutes for robotics (65-120 minutes) including surgical and docking time. No intraoperative complications occurred. The median hospital stay was 2 days (36-96 hours). No residual liquid was detected on follow-up after deroofing and fat tissue wadding technique. Conclusions: Cyst deroofing is an effective and durable treatment for symptomatic simple renal cysts. Robotics enables excellent tissue dissection and ergonomics. The perirenal fat tissue wadding of the cyst seems to reduce the recurrence rate. The ICG fluorescence technique allows for better identification of the cyst and safer surgical procedure.

Angiotensinogen and interleukin 18 in serum and urine of children with kidney cysts

BACKGROUND

The most common disease associated with the presence of kidney cysts in the population is autosomal dominant polycystic kidney disease (ADPKD), which finally leads to end-stage renal disease.

METHOD

The study evaluated serum and urinary concentration of angiotensinogen (AGT) and interleukin 18 (IL-18) in a group of 39 children with renal cysts of different aetiology.

RESULTS

Serum and urinary AGT concentration in children with renal cysts was higher compared to controls, regardless of the underlying background and gender. Serum IL-18 concentration was lower, in contrast, and the concentration of IL-18 in the urine did not differ between affected and healthy children. Negative correlation between urinary IL-18 concentration and systolic and mean arterial blood pressure was noted.

CONCLUSIONS

Higher AGT levels in serum and urine in children with renal cysts may indicate the activation of the renin-angiotensin-aldosterone system, including its intrarenal part, even before the onset of hypertension. Lower serum concentration of IL-18 in children with kidney cysts may indicate the loss of the protective role of this cytokine with the occurrence of hypertension.

Active Surveillance of Small (< 4 cm) Bosniak Category 2F, 3, and 4 Renal Lesions: What Happens on Imaging Follow-Up?

OBJECTIVE. The purpose of this study was to determine the percentage of small (< 4 cm) Bosniak category 2F, 3, and 4 lesions that regress during active surveillance. MATERIALS AND METHODS. In this retrospective study, a hospital database was searched from January 1, 2005, through September 9, 2017, for small (< 4 cm) Bosniak category 2F, 3, and 4 lesions studied with initial and follow-up unenhanced and contrast-enhanced CT or MRI. Prospective Bosniak categories were recorded. Two blinded radiologists retrospectively reassigned Bosniak categories to the initial and last follow-up studies. Interreader variability was analyzed. Rates of stability, regression, and progression were calculated and stratified by size. Logistic regression was used to assess the effects of lesion size, lesion growth, and duration of follow-up on the change in Bosniak categories. RESULTS. The search identified 123 patients (85 men, 38 women) with 138 renal lesions (according to the blinded readings, 83 Bosniak category 2F, 37 category 3, and 18 category 4) and followed for 1-12.3 years (median, 2.7 years). Fifty-one percent (70/138) of the lesions were smaller than 2 cm. Eighty-eight percent (73/83) of category 2F lesions were downgraded or remained stable. Forty-five percent (25/55) of category 3 or 4 lesions were downgraded to 2F or lower. Kappa values were 0.94 between the two readers and 0.72-0.76 between the readers and the prospective Bosniak categories. There was no association between initial size, change in size, or duration of follow-up and change in Bosniak category. CONCLUSION. Approximately one-half of small (< 4 cm) Bosniak category 3 and 4 cystic renal lesions were downgraded, and the majority (88%) of small Bosniak category 2F lesions regressed or remained stable during active surveillance. Therefore, small size should be a consideration for conservative management.

Active Surveillance Versus Nephron-Sparing Surgery for a Bosniak IIF or III Renal Cyst: A Cost-Effectiveness Analysis

OBJECTIVE

The objective of our study was to evaluate the cost-effectiveness of active surveillance (AS) versus nephron-sparing surgery (NSS) in patients with a Bosniak IIF or III renal cyst.

MATERIALS AND METHODS

Markov models were developed to estimate life expectancy and lifetime costs for 60-year-old patients with a Bosniak IIF or III renal cyst (the reference cases) managed by AS versus NSS. The models incorporated the malignancy rates, reclassification rates during follow-up, treatment effectiveness, complications and costs, and short- and long-term outcomes. An incremental cost-effectiveness analysis was performed to identify management preference under an assumed $75,000 per quality-adjusted life-year (QALY) societal willingness-to-pay threshold, using data from studies in the literature and the 2015 Medicare Physician Fee Schedule. The effects of key parameters were addressed in a multiway sensitivity analysis.

RESULTS

The prevalence of malignancy for Bosniak IIF and III renal cysts was 26% (25/96) and 52% (542/1046). Under base case assumptions for Bosniak IIF cysts, the incremental cost-effectiveness ratio of NSS relative to AS was $731,309 per QALY for women, exceeding the assumed societal willingness-to-pay threshold, and AS outperformed NSS for both life expectancy and cost for men. For Bosniak III cysts, AS yielded greater life expectancy (24.8 and 19.4 more days) and lower lifetime costs (cost difference of $12,128 and $11,901) than NSS for men and women, indicating dominance of AS over NSS. Superiority of AS held true in sensitivity analyses for men 46 years old or older and women 57 years old or older even when all parameters were set to favor NSS.

CONCLUSION

AS is more cost-effective than NSS for patients with a Bosniak IIF or III renal cyst.

[A child with severe growth delay and renal cysts]

We describe the case of a 5-year-old who came to our attention for a growth delay. Among the investigations planned because of the child's short stature, we performed an abdominal ultrasound showing normal-sized kidneys with signs of cortico-medullar de-differentiation, diffuse medullary hyperechogenicity with reduction of cortical thickness and cortical-medullary cysts. The ultrasound findings, also confirmed in MRI, led us to suspect a genetically determined cystic nephropathy of the nephronophthisis or medullary cystic disease type. No mutation was identified in NPHP1, HNFb1 and UMOD genes. Interestingly, laboratory investigations revealed a severe metabolic acidosis with normal renal function and hypokalemia. These findings are not characteristics of a nephronophthisis. We therefore also performed molecular analysis for distal tubular acidosis (dRTA) that showed the association of two genetic variants of ATP6V1B1 and SLC4A genes. These "double mutations" have been inherited from the mother, which however does not have the classic dRTA phenotype. These variants do not currently meet the criteria for a conclusive molecular diagnosis of dRTA but represent variants of uncertain clinical significance. However, considering the clinical and laboratory data one can reasonably conclude that the child has a "probable" diagnosis of distal tubular acidosis. The rapid recovery of staturo-ponderal growth after the start of alkalizing treatment supports our diagnostic hypothesis. The association between distal tubular acidosis and renal cysts is well described in the literature. The hypothesis is that chronic hypokalemia may play a possible role in the formation of renal cysts.

Urologic Diseases Germane to the Medical Renal Biopsy: Review of a Large Diagnostic Experience in the Context of the Renal Architecture and Its Environs

The kidney is one of the most complicated organs in development and is susceptible to more types of diseases than other organs. The disease spectrum includes developmental and cystic diseases, involvement by systemic diseases, iatrogenic complications, ascending infections and urinary tract obstruction, and neoplastic diseases. The diagnosis of kidney disease is unique involving 2 subspecialties, urologic pathology and renal pathology. Both renal and urologic pathologists employ the renal biopsy as a diagnostic modality. However, urologic pathologists commonly have a generous specimen in the form of a nephrectomy or partial nephrectomy while a renal pathologist requires ancillary modalities of immunofluorescence and electron microscopy. The 2 subspecialties differ in the disease spectrum they diagnose. This separation is not absolute as diseases of one subspecialty not infrequently appear in the diagnostic materials of the other. The presence of medical renal diseases in a nephrectomy specimen is well described and recommendations for reporting these findings have been formalized. However, urologic diseases appearing in a medical renal biopsy have received less attention. This review attempts to fill that gap by first reviewing the perirenal anatomy to illustrate why inadvertent biopsy of adjacent organs occurs and determine its incidence in renal biopsies followed by a discussion of gross anatomic features relevant to the microscopic domain of the medical renal biopsy. Unsuspected neoplasms and renal cysts and cystic kidney diseases will then be discussed as they create a diagnostic challenge for the renal pathologist who often has limited training and experience in these diseases.

mTORC1 Upregulation Leads to Accumulation of the Oncometabolite Fumarate in a Mouse Model of Renal Cell Carcinoma

Renal cell carcinomas (RCCs) are common cancers diagnosed in more than 350,000 people each year worldwide. Several pathways are de-regulated in RCCs, including mTORC1. However, how mTOR drives tumorigenesis in this context is unknown. The lack of faithful animal models has limited progress in understanding and targeting RCCs. Here, we generated a mouse model harboring the kidney-specific inactivation of Tsc1. These animals develop cysts that evolve into papillae, cystadenomas, and papillary carcinomas. Global profiling confirmed several metabolic derangements previously attributed to mTORC1. Notably, Tsc1 inactivation results in the accumulation of fumarate and in mTOR-dependent downregulation of the TCA cycle enzyme fumarate hydratase (FH). The re-expression of FH in cellular systems lacking Tsc1 partially rescued renal epithelial transformation. Importantly, the mTORC1-FH axis is likely conserved in human RCC specimens. We reveal a role of mTORC1 in renal tumorigenesis, which depends on the oncometabolite fumarate.

A Novel p.L145Q Mutation in the HNF1B Gene in a Case of Maturity-onset Diabetes of the Young Type 5 (MODY5)

Maturity-onset diabetes of the young (MODY) is an autosomal dominant form of early onset diabetes. The hepatocyte nuclear factor-1-beta (HNF1B) gene is responsible for MODY type 5 (MODY5) with distinctive clinical features, including pancreatic atrophy and renal disease. We herein report a Japanese case of young-onset diabetes with typical phenotypes of MODY5 and a novel heterozygous missense mutation (p.L145Q) in the HNF1B gene. The mutation was located in the Pit-Oct-Unc (POU)-specific domain, and the amino acid residue L145 was highly conserved among species. It is strongly suggested that this mutation explains the phenotypes of MODY5.

Renal cyst masses (Bosniak category II-III) may be over evaluated by the Bosniak criteria based on MR findings

A classification system of renal cysts developed by Bosniak is based on computed tomography (CT) findings and has been applied to deal with the complex cystic renal masses. Magnetic resonance (MR) has excellent soft-tissue resolution, it has been used to further evaluate some complex renal lesions, especially those suspected of containing soft tissue components and hyperattenuating cystic lesions seen on CT. Compared with CT, MR images may find additional information, which may lead to inconsistent classification. However, at present, there is no consensus on the treatment of these inconsistent lesions. This study aimed to investigate the value of MR in the evaluation of renal cystic masses by using the Bosniak classification system and improve understanding of the MR features of renal cyst masses.The present study retrospectively analyzed 35 renal cyst masses in 34 patients (10 men and 24 women with age from 20 to 65 years old, with an average of 49 ± 12.08), who underwent both MR and computed tomography (CT) examinations within 6 months (range from 1 to 135 days with an average of 11 ± 24.16 days). Twenty-four lesions (9 category III and 15 category IV on CT) received surgical treatment, 4 category IIF lesions on CT were upgraded to category III on MR, which were finally accepted operative resection. The remaining 7 lesions (category II-IIF on both CT and MR) were followed up for at least 3 years. For each lesion, size of both cyst and solid component, presence of calcification, number of septa, thickness of wall and septa, and appearance of enhancement were analyzed. Each lesion was categorized by using Bosniak criteria on CT and MR, respectively. The MR findings were compared with CT and pathology or follow-up results.On MR, categories of the lesions were as follows: category IIF (n = 7), III (n = 12), IV (n = 16). On CT, categories of the lesions were as follows: II (n = 3), IIF (n = 8), III (n = 9), and IV (n = 15). Findings on MR and CT images were inconsistent in 8 (23%) lesions. Among them, 3 category II lesions on CT were classified as category IIF on MR images, 4 category IIF lesions on CT were upgraded to category III on MR, and 1 category III lesions to category IV. In these lesions, MR detected more increased wall/septa thickness (n = 8) and septa number (n = 3) than CT, resulting in an upgrade in classification. Based on the pathological results, 5 of category III (5/9, 56%) and all category IV (15/15, 100%) lesions on CT images were malignant. On MR, 4 of category III (4/12, 33%) and all category IV (16/16, 100%) lesions were malignant.The renal cyst masses in some cases, especially category II to III lesions, may be over evaluated by the Bosniak criteria based on MR findings. It is necessary to combine MR features with CT findings in evaluation and management of these cases with renal cystic masses.

A novel mutation in the hepatocyte nuclear factor-1β gene in maturity onset diabetes of the young 5 with multiple renal cysts and pancreas hypogenesis: A case report

A 17-year-old Chinese male was hospitalized exhibiting hyperglycemia and increased serum urea nitrogen and creatinine levels in addition to weight loss. The patient was treated with gliclazide. The patient was 150 cm tall, weighed 35 kg and had no family history of diabetes or kidney disease. Physical examination revealed cephalus quadratus, rachitic rosary and a visible toe-out gait. Laboratory examinations revealed that the patient's fasting plasma glucose and glycosylated hemoglobin levels were markedly increased, fasting plasma C-peptide level was slightly increased and no peak 2 h postprandial was observed. Diabetic autoimmune antibodies [islet cell cytoplasmic autoantibodies (ICA), glutamic acid decarboxylase autoantibodies (GADA), isulinoma-2-associated autoantibodies (IA2A) and insulin autoantibodies (IAA)] were negative. Levels of serum electrolytes decreased, uric acid and parathyroid hormone increased, mild albuminuria was detected and there was a low proportion of urine. The patient also presented with low bone mass and cataracts. Abdominal computed tomography (CT) revealed a bilateral atrophic kidney with multiple renal cysts, primarily located at the junction of renal cortex and medulla, with a diameter of 0.3-0.7 cm. CT also revealed hypogenesis of the body and tail of the pancreas. In an oral glucose tolerance test, the mother and paternal uncle of the patient were diagnosed with type II diabetes and the patient's sister, maternal uncle and paternal grandpa were diagnosed with glucose tolerance impairment. Genetic testing revealed an unreported amino acid mutation in exon 2 of hepatocyte nuclear factor 1β (c.391C>T), a nonsense mutation of CAA to TAA at codon 131. This mutation was identified in the proband but not in any other family members.

Diverticular disease is associated with benign intra-abdominal cystic disease

BACKGROUND

Diverticular disease (DD) and hepatic and renal cysts have been linked with defects in collagen and dysfunctional matrix metalloproteinases.

METHODS

Consecutive abdominal computed tomography scans between January-July 2015 were prospectively studied to determine a correlation between visceral cysts and DD. Patients with a sigmoid colectomy for pathology other than DD and scans in which DD and/or solid organs were not fully visualized were excluded. A subgroup analysis was performed on youthful DD patients (<55 years of age, n = 32) vs. older controls (>55, n = 213).

RESULTS

238 DD patients (50.8% male) and 369 controls (40.5% male, p = .02) were included. Incidence of visceral cystic disease in DD patients vs. controls was 71.4% vs. 22.5% (p < 0.00001). Renal cysts, present in 53.4% of the DD patients and 18.7% of the controls (p < .00001), were more common than hepatic cysts in both groups. Hepatic cyst prevalence was 8.8 vs. 2.4% (p = .0008). In the subgroup analysis, cystic disease was present in 56.2% of youthful DD patients vs. 29.1% of older controls (p = .004).

CONCLUSIONS

A significant association between cystic disease and DD was demonstrated overall and in subgroup analysis inclusive of youthful DD patients and older controls. These findings suggest a global defect in connective tissue integrity in DD patients.

Outcomes and complications related to the management of Bosniak cystic renal lesions

OBJECTIVE

The objective of our study was to evaluate outcomes and complications related to the management of Bosniak category IIF, III, and IV renal cysts.

MATERIALS AND METHODS

For this multiinstitutional retrospective study, a Web-based Research Electronic Data Capture (REDCap) data registry was used to record data of 286 adult patients with 312 prospectively classified Bosniak IIF, III, and IV renal cysts diagnosed between January 2000 and October 2011. Included patients were managed by surgery (n = 86), percutaneous ablation (n = 19), or imaging surveillance of 1 year or more (n = 181). The median number of years of clinical surveillance was 2.4 years (range, 0-11.7 years), 2.6 years (range, 0.4-11.4 years), and 3.2 years (range, 1.1-11.6 years) for patients managed by surgery, ablation, and imaging surveillance, respectively. Pathologic and survival outcomes and complications related to management were evaluated.

RESULTS

The malignancy rate at surgical pathology was 38% (3/8) for Bosniak IIF, 40% (29/72) for Bosniak III, and 90% (18/20) for Bosniak IV renal cysts. There were no metastases or deaths (0/144) directly related to Bosniak IIF renal cysts. There were no deaths (0/113) directly related to Bosniak III renal cysts, although one patient (1/113) developed local progression and lung metastases after thermal ablation. One patient with a Bosniak IV renal cyst (1/29) presented with and died of metastatic disease. Moderate to severe complications occurred in 19% (16/86), 5% (1/19), and 0% (0/181) of patients managed by surgery, ablation, and imaging surveillance, respectively (p < 0.0001). Severe complications occurred in 7% (6/86) of surgical patients and included multiorgan failure (n = 2), acute myocardial infarction (n = 1), acute ischemic stroke (n = 1), conversion to hemodialysis-dependent chronic kidney disease (n = 1), and postoperative severe hemorrhage (n = 1).

CONCLUSION

There were no deaths from Bosniak IIF or III renal cysts regardless of management approach. Moderate to severe complications are frequent in patients managed by surgery.

Complex renal cysts associated with crizotinib treatment

An apparent causal association between crizotinib treatment and renal cyst development emerged during clinical trials in anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC). Serious adverse event (SAE) reports of renal cysts from a safety database of 1375 patients from four clinical trials were reviewed. A blinded, retrospective, independent radiologic review (IRR) was performed using scans from patients on study for ≥ 6 months in three clinical trials; risk factors for renal cyst development were assessed. Among 17 patients with renal cysts reported as SAEs, evidence of invasion into adjacent structures was noted in seven patients, with no evidence of malignancy found. These patients generally did not require dose reductions, none required permanent crizotinib discontinuation due to this AE, and most continued treatment with clinical benefit. In the blinded IRR, among 255 crizotinib-treated patients, 22%, 3%, and 2% had preexisting simple cysts, complex cysts, or both, respectively. At the 6-month tumor assessment, 9% of all patients had acquired new cysts, and 2% of patients with preexisting cysts had developed new cysts and enlargements (>50%) of preexisting simple cysts. Asians appeared to have an increased risk of developing new cysts on treatment; Koreans in particular had 5.18 times higher odds of developing cysts than non-Asians (95% confidence interval, 1.51-17.78; P = 0.05). Crizotinib treatment appears to be associated with an increased risk of development and progression of renal cysts in patients with ALK-positive NSCLC. While close monitoring is recommended, dosing modification was not generally necessary, allowing patients to remain on crizotinib treatment.

DICER1 mutations in childhood cystic nephroma and its relationship to DICER1-renal sarcoma

The pathogenesis of cystic nephroma of the kidney has interested pathologists for over 50 years. Emerging from its initial designation as a type of unilateral multilocular cyst, cystic nephroma has been considered as either a developmental abnormality or a neoplasm or both. Many have viewed cystic nephroma as the benign end of the pathologic spectrum with cystic partially differentiated nephroblastoma and Wilms tumor, whereas others have considered it a mixed epithelial and stromal tumor. We hypothesize that cystic nephroma, like the pleuropulmonary blastoma in the lung, represents a spectrum of abnormal renal organogenesis with risk for malignant transformation. Here we studied DICER1 mutations in a cohort of 20 cystic nephromas and 6 cystic partially differentiated nephroblastomas, selected independently of a familial association with pleuropulmonary blastoma and describe four cases of sarcoma arising in cystic nephroma, which have a similarity to the solid areas of type II or III pleuropulmonary blastoma. The genetic analyses presented here confirm that DICER1 mutations are the major genetic event in the development of cystic nephroma. Further, cystic nephroma and pleuropulmonary blastoma have similar DICER1 loss of function and 'hotspot' missense mutation rates, which involve specific amino acids in the RNase IIIb domain. We propose an alternative pathway with the genetic pathogenesis of cystic nephroma and DICER1-renal sarcoma paralleling that of type I to type II/III malignant progression of pleuropulmonary blastoma.

Regulation of STATs by polycystin-1 and their role in polycystic kidney disease

Autosomal-dominant polycystic kidney disease (ADPKD) is a common genetic disease caused by mutations in the gene coding for polycystin-1 (PC1). PC1 can regulate STAT transcription factors by a novel, dual mechanism. STAT3 and STAT6 are aberrantly activated in renal cysts. Genetic and pharmacological approaches to inhibit STAT3 or STAT6 have led to promising results in ADPKD mouse models. Here, we review current findings that lead to a model of PC1 as a key regulator of STAT signaling in renal tubule cells. We discuss how PC1 may orchestrate appropriate epithelial responses to renal injury, and how this system may lead to aberrant STAT activation in ADPKD thereby causing inappropriate activation of tissue repair programs that culminate in renal cyst growth and fibrosis.

Developmental signaling: does it bridge the gap between cilia dysfunction and renal cystogenesis?

For more than a decade, evidence has accumulated linking dysfunction of primary cilia to renal cystogenesis, yet molecular mechanisms remain undefined. The pathogenesis of renal cysts is complex, involving multiple cellular aberrations and signaling pathways. Adding to this complexity, primary cilia exhibit multiple roles in a context-dependent manner. On renal epithelial cells, primary cilia act as mechanosensors and trigger extracellular Ca(2+) influx in response to laminar fluid flow. During mammalian development, primary cilia mediate the Hedgehog (Hh), Wnt, and Notch pathways, which control cell proliferation and differentiation, and tissue morphogenesis. Further, experimental evidence suggests the developmental state of the kidney strongly influences renal cystic disease. Thus, we review evidence for regulation of Ca(2+) and cAMP, key molecules in renal cystogenesis, at the primary cilium, the role of Hh, Wnt, and Notch signaling in renal cystic disease, and the interplay between these developmental pathways and Ca(2+) signaling. Indeed if these developmental pathways influence renal cystogenesis, these may represent novel therapeutic targets that can be integrated into a combination therapy for renal cystic disease.

Renal cell carcinoma in a setting of chronic lithium toxicity

PATIENT

Female, 72 FINAL DIAGNOSIS: Renal cell carcinoma Symptoms: -

MEDICATION

- Clinical Procedure: - Specialty: Oncology.

OBJECTIVE

Challenging differential diagnosis.

BACKGROUND

Lithium salts are widely used in the treatment of affective disorders of the bipolar type. Lithium is a nephrotoxic substance which can cause both acute and chronic renal disease, including cyst formation. Cysts appear to predispose the kidney to renal cell carcinoma.

CASE REPORT

A case of renal cell carcinoma in a background of acquired cystic disease due to chronic lithium toxicity is described.

CONCLUSIONS

Kidneys with multiple cysts are at risk of renal cell carcinoma. Although it is difficult to determine if long term Lithium use renal cell carcinoma, patients leads to the development of on long-term lithium therapy should undergo regular renal function and imaging tests.

Cystic adnexal mass in a 16-year-old female: Ovarian pathology or complication of a Müllerian anomaly?

Patient: Female, 16

Final Diagnosis: Pelvic mass

Symptoms: None

Medication: None

Clinical Procedure: CT • MRI

Specialty: Diagnostic radiology • pediatrics

Androgen-STAT3 activation may contribute to gender disparity in human simply renal cysts

BACKGROUND

Simple renal cysts (SRC) are a common urological disease mostly in elderly, however the male-to-female ratio was 2.81. Androgen receptor (AR) activation was initially proposed as a vital signaling pathway in prostate cancer and consequent signal transducer and activator of transcription 3 (STAT3)-AR complex led an important putative mechanism by which prostate cells are sensitized with growth factor signals. However, in SRC disease, no related study emerged.

METHODS

30 patients with SRC and 20 age-matched healthy controls were recruited. Puncture biopsy was performed to acquire cyst-adjacent kidney tissue and normal kidney tissues were from healthy kidney donor who received living-related donor nephrectomy. The expression of STAT3 and androgen receptor was determined by immunohistochemical staining and western blotting. The in-vitro effect of androgen on human HK-2 (an immortalized proximal tubule epithelial cell line from normal adult human kidney) cells' STAT3 expression was analyzed as well.

RESULTS

Activated STAT3 was strongly expressed in tubular epithelial cells from kidneys of SRC patients, while it was barely found in normal kidneys. Meanwhile, the androgen receptor positive cyst epithelial cells and adjacent normal renal tubule cells were observed in kidneys from SRC patients, however, AR was weakly expressed in normal healthy male kidneys, statistically significant differences existed. In-vitro experiment demonstrated that when treated with exogenous added androgen, the expression level of STAT3 in HK-2 cells was significantly elevated.

CONCLUSIONS

Our data raised the possible novel evidence that androgen-STAT3 activation might contribute to gender disparity in human SRC disease and clarification the esoteric mechanisms will provide us attractive therapy target for cystic kidney disease.

Current insights into renal ciliopathies: what can genetics teach us?

Ciliopathies are a group of clinically and genetically overlapping disorders whose etiologies lie in defective cilia. These are antenna-like organelles on the apical surface of numerous cell types in a variety of tissues and organs, the kidney included. Cilia play essential roles during development and tissue homeostasis, and their dysfunction in the kidney has been associated with renal cyst formation and renal failure. Recently, the term "renal ciliopathies" was coined for those human genetic disorders that are characterized by nephronophthisis, cystic kidneys or renal cystic dysplasia. This review focuses on renal ciliopathies from a human genetics perspective. We survey the newest insights with respect to gene identification and genotype-phenotype correlations, and we reflect on candidate ciliopathies. The opportunities and challenges of next-generation sequencing (NGS) for genetic renal research and clinical DNA diagnostics are also reviewed, and we discuss the contribution of NGS to the development of personalized therapy for patients with renal ciliopathies.

Cystic kidney diseases: many ways to form a cyst

Renal cysts are a common radiological finding in both adults and children. They occur in a variety of conditions, and the clinical presentation, management, and prognosis varies widely. In this article, we discuss the major causes of renal cysts in children and adults with a particular focus on the most common genetic forms. Many cystoproteins have been localized to the cilia centrosome complex (CCC). We consider the evidence for a universal 'cilia hypothesis' for cyst formation and the evidence for non-ciliary proteins in cyst formation.

Milk of calcium (MOC) cysts masquerading as renal calculi - a trap for the unwary

Milk of calcium (MOC) is a colloidal suspension of calcium salts occurring in calyceal cysts and diverticula. Although reported to be rare, in fact it seems to be more common than previously thought. It has characteristic appearances on plain x-rays, ultrasound, and CT imaging particularly in the prone and supine positions. Often entirely asymptomatic, its appearance may be mistaken for renal stones on radiography or angiomyolipomas on ultrasonography. In this paper, a series of cases is presented outlining its characteristic features and reviewing the relevant literature.

Renal cysts as strongest association with abdominal aortic aneurysm in elderly

OBJECTIVE

The aim of this study is to investigate the positive association between the presence of renal cysts and AAA.

PATIENTS AND METHODS

A retrospective chart review on the clinical data of 396 consecutive patients, who underwent CT scans for preoperative evaluation of thoracic and cardiovascular surgery in Sapporo Medical University from the period of January 2007 to December 2008, was conducted.

RESULTS

When comparing patients with renal cysts (n = 164) to those without (n = 233), there was a statistically significant difference between the presence of renal cysts and male gender (p = 0.007), hypertension (p = 0.003), and AAA (p < 0.001) on univariate analysis. In addition, when comparing patients with AAA to those without, although COPD but not AAA was associated with renal cysts in less than 65 years old, the presence of renal cysts was the strongest association with AAA among patients belonging to the 65 to 74 years old group and over 75 years old group on multivariate analysis.

CONCLUSIONS

There is a statistically higher incidence of renal cysts in patients with AAA compared to patients without AAA in the group of elder cardiovascular patients. It is likely that AAA and renal cysts share a common pathogenesis.

Mutations in hepatocyte nuclear factor-1beta and their related phenotypes

BACKGROUND

Hepatocyte nuclear factor-1 beta (HNF-1beta) is a widely distributed transcription factor which plays a critical role in embryonic development of the kidney, pancreas, liver, and Mullerian duct. Thirty HNF-1beta mutations have been reported in patients with renal cysts and other renal developmental disorders, young-onset diabetes, pancreatic atrophy, abnormal liver function tests, and genital tract abnormalities.

METHODS

We sequenced the HNF-1beta gene in 160 unrelated subjects with renal disease, 40% of whom had a personal/family history of diabetes.

RESULTS

Twenty three different heterozygous HNF-1beta mutations were identified in 23/160 subjects (14%), including 10 novel mutations (V61G, V110G, S148L, K156E, Q176X, R276Q, S281fsinsC, R295P, H324fsdelCA, Q470X). Seven (30%) cases were proven to be due to de novo mutations. Renal cysts were found in 19/23 (83%) patients (four with glomerulocystic kidney disease, GCKD) and diabetes in 11/23 (48%, while three other families had a family history of diabetes. Only 26% of families met diagnostic criteria for maturity-onset diabetes of the young (MODY) but 39% had renal cysts and diabetes (RCAD). We found no clear genotype/phenotype relationships.

CONCLUSION

We report the largest series to date of HNF-1beta mutations and confirm HNF-1beta mutations as an important cause of renal disease. Despite the original description of HNF-1beta as a MODY gene, a personal/family history of diabetes is often absent and the most common clinical manifestation is renal cysts. Molecular genetic testing for HNF-1beta mutations should be considered in patients with unexplained renal cysts (including GCKD), especially when associated with diabetes, early-onset gout, or uterine abnormalities.

Extraglomerular lesions in kidneys of mink with encephalitozoonosis

Extraglomerular renal lesions were studied by light and electron microscopy in 13 farmed mink which showed cataractous eyes associated with spontaneous encephalitozoonosis. The extraglomerular renal lesions consisted of multiple renal cysts, multifocal-to-coalescing interstitial nephritis and vasculitis. Tubular cysts of varying size were present in the corticomedullary junction and medulla. The inflammatory infiltrates were composed mostly of lymphocytes and plasma cells and usually accompanied an interstitial fibrosis. Vasculitis, perivasculitis and sclerotic arteries were frequently seen.