Renal cell carcinoma in autosomal dominant polycystic kidney disease

Efficacy of 18F-Fluorodeoxyglucose positron emission tomography/computed tomography for detecting renal cell carcinoma in patients with end-stage renal disease

PURPOSE

Dialysis patients are at an increased risk of developing renal cell carcinoma (RCC); however, differentiating between RCC and benign cysts can sometimes be difficult using modalities, such as computed tomography (CT) and ultrasonography. 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET)/CT efficiently detects malignant tumors; however, physiological accumulation of FDG in the kidney limits its efficacy in detecting renal tumors. However, in patients with severely impaired renal function, the renal accumulation of FDG is decreased, possibly improving the detection of renal malignancies in this patient population. This study evaluated the usefulness of FDG-PET/CT as a screening tool for detecting RCC in patients with end-stage renal disease.

MATERIALS AND METHODS

This prospective study recruited 150 participants from 2012 to 2016 who were on dialysis or underwent renal transplantation and were on dialysis until transplantation. FDG-PET/CT was performed to screen for RCC. Three radiologists independently evaluated the images. No protocol was defined for the additional management of positive examinations, leaving decisions to the discretion of each participant. Negative examinations were observed until the end of 2019.

RESULTS

In total, 150 participants (mean age, 58 ± 13 years; 105 men) underwent FDG-PET/CT. Twenty patients (13.4%) were diagnosed as positive. Fifteen patients underwent additional examinations and/or procedures, and RCC was found in seven patients. Of the four patients who underwent surgical resection, the pathological results were clear cell RCC in one, papillary RCC in one, and acquired cystic disease-associated RCC in two. Two participants were diagnosed with RCC on bone biopsy, and one was diagnosed on dynamic CT but opted for observation. The sensitivity, specificity, and negative predictive value were 100%, 93.9%, and 100%, respectively.

CONCLUSION

FDG-PET/CT was useful for detecting RCC in patients with end-stage renal disease. Our findings show the potential use of FDG-PET/CT as a screening tool for RCC in this patient population.

The Link between Autosomal Dominant Polycystic Kidney Disease and Chromosomal Instability: Exploring the Relationship

In autosomal dominant polycystic kidney disease (ADPKD) with germline mutations in a PKD1 or PKD2 gene, innumerable cysts develop from tubules, and renal function deteriorates. Second-hit somatic mutations and renal tubular epithelial (RTE) cell death are crucial features of cyst initiation and disease progression. Here, we use established RTE lines and primary ADPKD cells with disease-associated PKD1 mutations to investigate genomic instability and DNA damage responses. We found that ADPKD cells suffer severe chromosome breakage, aneuploidy, heightened susceptibility to DNA damage, and delayed checkpoint activation. Immunohistochemical analyses of human kidneys corroborated observations in cultured cells. DNA damage sensors (ATM/ATR) were activated but did not localize at nuclear sites of damaged DNA and did not properly activate downstream transducers (CHK1/CHK2). ADPKD cells also had the ability to transform, as they achieved high saturation density and formed colonies in soft agar. Our studies indicate that defective DNA damage repair pathways and the somatic mutagenesis they cause contribute fundamentally to the pathogenesis of ADPKD. Acquired mutations may alternatively confer proliferative advantages to the clonally expanded cell populations or lead to apoptosis. Further understanding of the molecular details of aberrant DNA damage responses in ADPKD is ongoing and holds promise for targeted therapies.

Metastatic Renal Cell Carcinoma in a Patient With Autosomal Dominant Polycystic Kidney Disease

ABSTRACT

Autosomal dominant polycystic kidney disease (ADPKD) manifests as multiple cysts in the kidneys and liver but can also present with musculoskeletal and cardiovascular abnormalities. ADPKD patients are at increased risk for renal cell carcinoma development. We show the FDG PET/CT findings in a patient with renal cell carcinoma secondary to ADPKD and complicated by worsening pulmonary metastasis. The primary renal tumor shows intense FDG uptake despite no suspicious features with contrast CT.

Cilia and Cancer: From Molecular Genetics to Therapeutic Strategies

Cilia are microtubule-based organelles that project from the cell surface with motility or sensory functions. Primary cilia work as antennae to sense and transduce extracellular signals. Cilia critically control proliferation by mediating cell-extrinsic signals and by regulating cell cycle entry. Recent studies have shown that primary cilia and their associated proteins also function in autophagy and genome stability, which are important players in oncogenesis. Abnormal functions of primary cilia may contribute to oncogenesis. Indeed, defective cilia can either promote or suppress cancers, depending on the cancer-initiating mutation, and the presence or absence of primary cilia is associated with specific cancer types. Together, these findings suggest that primary cilia play important, but distinct roles in different cancer types, opening up a completely new avenue of research to understand the biology and treatment of cancers. In this review, we discuss the roles of primary cilia in promoting or inhibiting oncogenesis based on the known or predicted functions of cilia and cilia-associated proteins in several key processes and related clinical implications.

Consensus document on autosomal dominant polycystic kindey disease from the Spanish Working Group on Inherited Kindey Diseases. Review 2020

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent cause of genetic renal disease and accounts for 6-10% of patients on kidney replacement therapy (KRT). Very few prospective, randomized trials or clinical studies address the diagnosis and management of this relatively frequent disorder. No clinical guidelines are available to date. This is a revised consensus statement from the previous 2014 version, presenting the recommendations of the Spanish Working Group on Inherited Kidney Diseases, which were agreed to following a literature search and discussions. Levels of evidence mostly are C and D according to the Centre for Evidence-Based Medicine (University of Oxford). The recommendations relate to, among other topics, the use of imaging and genetic diagnosis, management of hypertension, pain, cyst infections and bleeding, extra-renal involvement including polycystic liver disease and cranial aneurysms, management of chronic kidney disease (CKD) and KRT and management of children with ADPKD. Recommendations on specific ADPKD therapies are provided as well as the recommendation to assess rapid progression.

Polycystic Kidney/Liver Disease

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder that leads to chronic kidney disease and end-stage kidney disease (ESKD). Polycystic liver disease (PCLD) is the most common extrarenal manifestation of ADPKD. Though isolated PCLD and PCLD due to ADPKD are genetically distinct, they follow a similar clinical course of hepatomegaly from multiple cysts with preserved liver function. Tolvaptan use in ADPKD can slow down the deterioration of renal function and growth of cysts. Somatostatin analogs can slow the growth of polycystic livers but the effect is short-lived. The only curative therapy for PCLD is liver transplantation. Renal transplantation can significantly improve survival in patients with ESKD due to ADPKD.

Hereditary Renal Cell Carcinoma

BACKGROUND: Hereditary renal cell carcinoma (RCC) is a complex and rapidly evolving topic as there is a growing body of literature regarding inherited syndromes and mutations associated with an increased risk of RCC. OBJECTIVES: We sought to systematically review 13 hereditary syndromes associated with RCC; von Hippel-Lindau Disease associated RCC (VHLRCC), BAP-1 associated clear cell RCC (BAPccRCC), Familial non-von Hippel Lindau clear cell RCC (FccRCC), Tuberous Sclerosis Complex associated RCC (TSCRCC), Birt-Hogg-Dub e ´ Syndrome associated RCC (BHDRCC), PTEN Hamartoma Tumor Syndrome associated RCC (PHTSRCC), Microphthalmia-associated Transcription Family translocation RCC (MiTFtRCC), RCC with Chromosome 6p Amplification (TFEBRCC), Autosomal Dominant Polycystic Kidney Disease Associated RCC (ADPKDRCC), Hereditary Leiomyomatosis associated RCC (HLRCC), Succinate Dehydrogenase RCC (SDHRCC), Hereditary Papillary RCC (HPRCC), and ALK-Rearrangement RCC (ALKRCC). RESULTS: Hereditary RCC is generally associated with early age of onset, multifocal and/or bilateral lesions, and aggressive disease course. VHLRCC, BAPccRCC, FccRCC, and certain mutations resulting in SDHRCC are associated with clear cell RCC (ccRCC). HPRCC is associated with Type 1 papillary RCC. HLRCC is associated with type 2 papillary RCC. BHDRCC is associated with Chromophobe RCC. TSCRCC, PHTSRCC, MiTFtRCC, TFEBRCC, ADPKDRCC, certain SDHRCC and ALKRCC have variable histology. CONCLUSIONS: There has been tremendous advancement in our understanding of the pathophysiology of hereditary RCC. Ongoing research will refine our understanding of hereditary RCC and its therapeutic targets.

Protein Kinase A Downregulation Delays the Development and Progression of Polycystic Kidney Disease

Background: Upregulation of cAMP-dependent and -independent PKA signaling is thought to promote cystogenesis in polycystic kidney disease (PKD). PKA-I regulatory subunit RIα is increased in kidneys of orthologous mouse models. Kidney-specific knockout of RIα upregulates PKA activity, induces cystic disease in wild-type mice, and aggravates it in Pkd1 ^RC/RC mice. Methods: PKA-I activation or inhibition was compared to EPAC activation or PKA-II inhibition using Pkd1 ^RC/RC metanephric organ cultures. The effect of constitutive PKA (preferentially PKA-I) downregulation in vivo was ascertained by kidney-specific expression of a dominant negative RIαB allele in Pkd1 ^RC/RC mice obtained by crossing Prkar1α ^R1αB/WT, Pkd1 ^RC/RC, and Pkhd1-Cre mice (C57BL/6 background). The effect of pharmacologic PKA inhibition using a novel, selective PRKACA inhibitor (BLU2864) was tested in mIMCD3 3D cultures, metanephric organ cultures, and Pkd1 ^RC/RC mice on a C57BL/6 x 129S6/Sv F1 background. Mice were sacrificed at 16 weeks of age. Results: PKA-I activation promoted and inhibition prevented ex vivo P-Ser133 CREB expression and cystogenesis. EPAC activation or PKA-II inhibition had no or only minor effects. BLU2864 inhibited in vitro mIMCD3 cystogenesis and ex vivo P-Ser133 CREB expression and cystogenesis. Genetic downregulation of PKA activity and BLU2864 directly and/or indirectly inhibited many pro-proliferative pathways and were both protective in vivo BLU2864 had no detectable on- or off-target adverse effects. Conclusions: PKA-I is the main PKA isozyme promoting cystogenesis. Direct PKA inhibition may be an effective strategy to treat PKD and other conditions where PKA signaling is upregulated. By acting directly on PKA, the inhibition may be more effective than or substantially increase the efficacy of treatments that only affect PKA activity by lowering cAMP.

Multiregion sequencing of sarcomatoid renal cell carcinoma arising from autosomal dominant polycystic kidney disease

Background

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited cystic kidney disease associated with a spectrum of various renal and extrarenal manifestations, including increased risk of kidney cancers. Here, we present the initial molecular description of sarcomatoid renal cell carcinoma (sRCC) arising in the setting of ADPKD.

Methods

Multiregion whole‐exome sequencing and whole transcriptomic sequencing were used to examine intratumoral molecular heterogeneity among histologically‐distinct spindle (sarcomatoid), epithelioid, or biphasic compartments within the tumor and compared with the non‐malignant ADPKD component.

Results

Spindle and biphasic components harbored several overlapping driver gene mutations, but do not share any with the epithelioid component. Mutations in ATM, CTNNB1, and NF2 were present only in the biphasic and spindle components, while mutations in BID, FLT3, ARID1B, and SMARCA2 were present only in the epithelioid component. We observed dichotomous evolutionary pathways in the development of epithelioid and spindle compartments, involving early mutations in TP53 and ATM/CTNNB1/NF2 respectively. Wnt, PI3K‐mTOR, and MAPK signaling pathways, known key mechanisms involved in ADPKD development, featured prominently in the sarcomatoid component.

Conclusion

This highlights that common pro‐oncogenic signals are present between ADPKD and sRCC providing insights into their shared pathobiology.

[What is evidence-based in the treatment of autosomal dominant polycystic kidney disease?]

The cystic transformation of the kidneys and liver are the most common symptoms of autosomal dominant polycystic kidney disease (prevalence 1:400-1:1000). A set of other manifestations can be observed less frequently, such as intracranial aneurysms. End-stage renal disease affects 50% of patients by the age of 70 years. To date, a targeted treatment is only available for patients at risk of rapidly progressive kidney failure. In 2015, the vasopressin receptor antagonist tolvaptan was approved in Germany for slowing down the decline of renal function in autosomal dominant polycystic kidney disease. Selecting the patients that benefit from tolvaptan treatment remains a major challenge. In recent years numerous clinical trials were carried out showing unspecific approaches to slow down the decline in renal function: strictly controlling blood pressure is one of the most important factors. Furthermore, unspecific approaches comprise suppression of vasopressin by sufficient fluid intake and restricted intake of salt. Weight reduction is recommended for obese patients. Lacking more causal approaches, these unspecific measures should be exploited in all patients. Currently, preclinical and clinical trials are testing numerous agents for the establishment of targeted treatment against the cystic degeneration of the kidneys and liver. This also includes dietary approaches. So far, in contrast to other genetic diseases, there are currently no gene therapy approaches for autosomal dominant polycystic kidney disease.

Incidental occurrence of papillary renal cell carcinoma in the native kidney with autosomal dominant polycystic kidney disease after renal transplantation: A case report

Autosomal dominant polycystic kidney disease (ADPKD) is one of the best-known genetic diseases. Almost half of the patients with ADPKD will develop end-stage renal disease, and the majority of patients are treated with renal transplantation. The current study presents a case that developed papillary renal cell carcinoma (PRCC) in the native right kidney 10 years after renal transplantation. PRCC is a not common malignant tumour entity (18.5% of all cases of renal cell carcinoma) compared with common clear cell renal carcinoma (65-70% of all cases of RCC).

From kidney injury to kidney cancer

Epidemiologic studies document strong associations between acute or chronic kidney injury and kidney tumors. However, whether these associations are linked by causation, and in which direction, is unclear. Accumulating data from basic and clinical research now shed light on this issue and prompt us to propose a new pathophysiological concept with immanent implications in the management of patients with kidney disease and patients with kidney tumors. As a central paradigm, this review proposes the mechanisms of kidney damage and repair that are active during acute kidney injury but also during persistent injuries in chronic kidney disease as triggers of DNA damage, promoting the expansion of (pre-)malignant cell clones. As renal progenitors have been identified by different studies as the cell of origin for several benign and malignant kidney tumors, we discuss how the different types of kidney tumors relate to renal progenitors at specific sites of injury and to germline or somatic mutations in distinct signaling pathways. We explain how known risk factors for kidney cancer rather represent risk factors for kidney injury as an upstream cause of cancer. Finally, we propose a new role for nephrologists in kidney cancer (i.e., the primary and secondary prevention and treatment of kidney injury to reduce incidence, prevalence, and recurrence of kidney cancer).

Renal cell carcinoma in native nephrectomy specimens of autosomal dominant polycystic kidney disease (ADPKD) patients with end-stage renal disease: Findings from an Australian transplant center

Objectives:

The aim of this study was to present a contemporary review of renal cell carcinoma (RCC) in native nephrectomy (NN) specimens of patients with autosomal dominant polycystic kidney disease (ADPKD) and end-stage renal disease (ESRD).

Materials (patients) and methods:

A retrospective review of all ADPKD patients who underwent NN from 1 October 2010 to 31 July 2019 was performed. Data was collected on demographics, length of time on renal replacement therapy, indications for surgery, perioperative details, and histology.

Results:

In total, 32 NNs were performed in our study period with 12.5% ( n=4) histologically diagnosed with RCC, consisting of 75% ( n=3) Type 1 papillary RCC (p RCC) and 25% ( n=1) clear cell RCC. Average age of ADPKD patients with ESRD diagnosed with RCC was 67±5.9 years. Average time on dialysis for RCC and non-RCC patients was 35.75±46.28 and 22.04±24.33 months, respectively. We did not find a significant correlation between the diagnosis of RCC and time on dialysis.

Conclusion:

Our contemporary series shows a significant proportion of ADPKD patients with ESRD undergoing NN have RCC. Compared to previously published datasets, our patients are older, and selective to those with very large kidneys and lesions suspicious for RCC. While there may be a role in imaging native kidneys with ADPKD to rule out suspicious lesions, it must be balanced against the cost, radiation exposure, and potential harm from an increased rate of nephrectomy that may ensue for suspicious lesions found on screening.

Level of evidence:

Not applicable for this multicentre audit.

Renal Squamous Cell Carcinoma-related Polymyositis in a Patient with Autosomal Dominant Polycystic Kidney Disease

A 74-year-old Japanese woman diagnosed with autosomal dominant polycystic kidney disease (ADPKD) was admitted to our institute for the further examination of right-side groin pain developing in the past week. The patient was diagnosed with polymyositis (PM). Diagnostic imaging showed a mass lesion measuring 8 cm and a renal stone in the right kidney. Immediately following surgical resection of the right kidney, the patient's serum CK decreased to the normal range. A histopathological analysis showed well-differentiated squamous cell carcinoma. In conclusion, this case showed a close relationship between the occurrence of squamous cell carcinoma and the development of PM in an ADPKD patient.

Sarcomatoid renal cell carcinoma with autosomal dominant polycystic kidney disease: a case report and literature review

Diagnosis of renal cell carcinoma (RCC) in patients with autosomal dominant polycystic kidney disease (ADPKD) is challenging and often delayed due to accompanying multiple renal cysts. Sometimes, it is difficult to distinguish RCC from cyst infection or hemorrhage. We herein present the case of a patient with ADPKD undergoing long-term hemodialysis whose sarcomatoid RCC was difficult to diagnose and was confirmed via nephrectomy. A 53-year-old male, undergoing hemodialysis since 20 years for end-stage renal disease secondary to ADPKD, was admitted to our hospital with a 3-week history of fever at > 38 °C and right flank pain. Clinical manifestations were compatible with cyst infection. Magnetic resonance images of the lesion identified in the lower right kidney, revealing slightly high signal intensity on T1-weighted images, low signal intensity on T2 weighted images, and restricted diffusion on diffusion-weighted images, were also consistent with those of cyst infection. Therefore, antibiotic therapy with ciprofloxacin, doripenem, and vancomycin was initiated. However, the patient's symptoms did not improve. Consequently, right nephrectomy was performed for both diagnosis and treatment, which revealed a sarcomatoid RCC with metastasis to the regional lymph node. The patient gradually developed cachexia and died on day 106 post-admission. The present case illustrates the difficulty of diagnosing RCC in patients with ADPKD, particularly sarcomatoid RCC, which is a rare and aggressive variant of RCC, even with the use of various types of imaging modalities. An early decision of nephrectomy may be necessary in such cases.

Novel non-cystic features of polycystic kidney disease: having new eyes or seeking new landscapes

For decades, researchers have been trying to decipher the complex pathophysiology of autosomal dominant polycystic kidney disease (ADPKD). So far these efforts have led to clinical trials with different candidate treatments, with tolvaptan being the only molecule that has gained approval for this indication. As end-stage kidney disease due to ADPKD has a substantial impact on health expenditures worldwide, it is likely that new drugs targeting kidney function will be developed. On the other hand, recent clinical observations and experimental data, including PKD knockout models in various cell types, have revealed unexpected involvement of many other organs and cell systems of variable severity. These novel non-cystic features, some of which, such as lymphopenia and an increased risk to develop infections, should be validated or further explored and might open new avenues for better risk stratification and a more tailored approach. New insights into the aberrant pathways involved with abnormal expression of PKD gene products polycystin-1 and -2 could, for instance, lead to a more directed approach towards early-onset endothelial dysfunction and subsequent cardiovascular disease. Furthermore, a better understanding of cellular pathways in PKD that can explain the propensity to develop certain types of cancer can guide post-transplant immunosuppressive and prophylactic strategies. In the following review article we will systematically discuss recently discovered non-cystic features of PKD and not well-established characteristics. Overall, this knowledge could enable us to improve the outcome of PKD patients apart from ongoing efforts to slow down cyst growth and attenuate kidney function decline.

Pathologic Lesions of the Budgett Frog (Lepidobatrachus laevis), an Emerging Laboratory Animal Model

Lepidobatrachus laevis, commonly called the Budgett frog, is a member of the horned frog family (Ceratophryidae), which has become increasingly popular among amphibian hobbyists. L. laevis is also used in biologic research on embryonic development, providing a novel model species for the study of organogenesis, regeneration, evolution, and biologic scaling. However, little scientific literature details disease processes or histologic lesions in this species. Our objective was to describe spontaneous pathologic lesions in L. laevis to identify disease phenotypes. We performed a retrospective analysis of 14 captive L. laevis frogs (wild-caught and captive-bred), necropsied at the NC State University College of Veterinary Medicine between 2008 and 2018. The majority of frogs exhibited renal changes, including varying combinations of tubular epithelial binucleation, karyomegaly, and cytoplasmic vacuolation; polycystic kidney disease; and renal carcinoma. Many of the renal changes are reminiscent of a condition described in Japanese (Bufo japonicus) and Chinese (Bufo raddei) toad hybrids that progresses from tubular epithelial atypia and tubular dilation to polycystic kidney disease to renal carcinoma. A second common finding was variably sized, randomly distributed bile duct clusters (biliary proliferation). Other noteworthy findings included regional or generalized edema, intestinal adenocarcinoma, aspiration pneumonia, and parasitism. This retrospective analysis is the first description of histologic lesions identified in captive L. laevis populations, providing new insight into spontaneous disease processes occurring in this species for use in disease diagnosis and clinical management.

Prevalence, risk factors and disease knowledge of polycystic kidney disease in Pakistan

Polycystic kidneys disease refers to cyst(s) formation in kidneys with severe consequences of end stage renal disease thus have higher mortality. It is a common genetic disease occurring either as autosomal dominant polycystic kidney (ADPKD) or autosomal recessive polycystic kidney disease (ARPKD) with prevalence rates of 1/1000 and 1/40,000 respectively. Dominant forms presenting in later (>30) while recessive in earlier ages (infancy) and affecting both sexes and almost all race. The patient experiences many renal as well as extra-renal manifestations with marked hypertension and cyst formation in other organs predominantly in liver. Due to genetic basis, positive family history is considered as major risk factor. Ultrasonography remains the main stay of diagnosis along with family history, by indicating increased renal size and architectural modifications. Initially disease remains asymptomatic, later on symptomatic treatment is suggested with surgical interventions like cyst decortications or drainage. Dialysis proved to be beneficial in end stage renal disease. However renal transplantation is the treatment of choice.

The Incidences and Characteristics of Various Cancers in Patients on Dialysis: a Korean Nationwide Study

BACKGROUND

The numbers of patients on dialysis and their life expectancies are increasing. Reduced renal function is associated with an increased risk of cancer, but the cancer incidence and sites in dialysis patients compared with those of the general population require further investigation. We investigated the incidences of various cancers in dialysis patients in Korea and used national health insurance data to identify cancers that should be screened in dialysis clinics.

METHODS

We accessed the Korean National Health Insurance Database and excerpted data using the International Classification of Disease codes for dialysis and malignancies. We included all patients who commenced dialysis between 2004 and 2013 and selected the same number of controls via propensity score matching.

RESULTS

A total of 48,315 dialysis patients and controls were evaluated; of these, 2,504 (5.2%) dialysis patients and 2,201 (4.6%) controls developed cancer. The overall cancer risk was 1.54-fold higher in dialysis patients than in controls (adjusted hazard ratio, 1.71; 95% confidence interval, 1.61-1.81). The cancer incidence rate (incidence rate ratio [IRR], 3.27) was especially high in younger dialysis patients (aged 0-29 years). The most common malignancy of end-stage renal disease patients and controls was colorectal cancer. The major primary cancer sites in dialysis patients were liver and stomach, followed by the lung, kidney, and urinary tract. Kidney cancer exhibited the highest IRR (6.75), followed by upper urinary tract (4.00) and skin cancer (3.38). The rates of prostate cancer (0.54) and oropharyngeal cancer (0.72) were lower than those in the general population.

CONCLUSION

Dialysis patients exhibited a higher incidence of malignancy than controls. Dialysis patients should be screened in terms of colorectal, liver, lung, kidney and urinary tract malignancies in dialysis clinics.

ADPKD-what the radiologist should know

Autosomal dominant polycystic kidney disease (ADPKD) is the most common renal genetic disorder and a leading cause of end stage renal failure (ESRF) affecting over 12 million people worldwide. Whilst the mainstay of diagnosis has historically favoured the imaging domain, the progression of disease was until very recently thought to be best monitored via biochemical analysis, i.e. measurement of estimated glomerular filtration rate. Imaging modalities such as sonography, CT and MRI have more recently proven to be key in monitoring disease progression. As much as half of the renal parenchyma can be lost with no real derangement in renal function. Tolvaptan, a vasopressin antagonist has been shown to slow disease progression and preserve renal function. Here we discuss at length the pathogenesis of ADPKD, the various diagnostic challenges surrounding its evaluation, new treatment options and monitoring of disease progression via serial imaging. We also propose monitoring of the efficacy of Tolvaptan at slowing the rate of deterioration in renal function in patients with ADPKD through MRI guided volumetric analysis of the kidneys.

Change in kidney volume after kidney transplantation in patients with autosomal polycystic kidney disease

Background

The indication to bilateral nephrectomy in patients with autosomal dominant polycystic kidney scheduled for kidney transplantation is controversial. Indeed, the progressive enlargement of cysts may increase the risk of complications and the need for nephrectomy. However, very few studies investigated the change in kidney volume after kidney transplantation.

Material and methods

In this prospective cohort study, the change in native kidney volume in polycystic patients was evaluated with magnetic resonance imaging. Forty patients were included in the study. Kidney diameters and total kidney volume were evaluated with magnetic resonance imaging in patients who underwent simultaneous nephrectomy and kidney transplantation and in patients with kidney transplant alone, before transplantation and 1 year after transplantation.

Results

There was a significant reduction of kidney volume after transplantation, with a mean degree of kidney diameters reduction varying from 12.24% to 14.43%. Mean total kidney volume of the 55 kidney considered in the analysis significantly reduced from 1617.94 ± 833.42 ml to 1381.42 ± 1005.73 ml (P<0.05), with a mean rate of 16.44% of volume decrease. More than 80% of patients had a volume reduction in both groups.

Conclusions

Polycystic kidneys volume significantly reduces after kidney transplantation, and this would reduce the need for prophylactic bilateral nephrectomy in asymptomatic patients.

Polycystic kidney disease

Cystic kidneys are common causes of end-stage renal disease, both in children and in adults. Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are cilia-related disorders and the two main forms of monogenic cystic kidney diseases. ADPKD is a common disease that mostly presents in adults, whereas ARPKD is a rarer and often more severe form of polycystic kidney disease (PKD) that usually presents perinatally or in early childhood. Cell biological and clinical research approaches have expanded our knowledge of the pathogenesis of ADPKD and ARPKD and revealed some mechanistic overlap between them. A reduced 'dosage' of PKD proteins is thought to disturb cell homeostasis and converging signalling pathways, such as Ca²⁺, cAMP, mechanistic target of rapamycin, WNT, vascular endothelial growth factor and Hippo signalling, and could explain the more severe clinical course in some patients with PKD. Genetic diagnosis might benefit families and improve the clinical management of patients, which might be enhanced even further with emerging therapeutic options. However, many important questions about the pathogenesis of PKD remain. In this Primer, we provide an overview of the current knowledge of PKD and its treatment.

The incidence of urinary tract cancers is related to preserved diuresis: a single-center report

PURPOSE

Residual diuresis progressively decreases with longer dialysis vintage, and higher incidence of renal and urinary tract cancers was often observed in hemodialyzed patients compared to the general population so we hypothesized that patients without preserved residual diuresis have higher risk of renal and urinary tract cancers than patients with preserved residual diuresis.

METHODS

Retrospective clinical data and pathology reports were completed for 307 uremic patients undergoing chronic hemodialysis. Patients were divided into two subgroups regarding residual diuresis: the first group with residual diuresis < 500 mL, 133 of 173 (76.8%) patients from this group were completely anuric, and the second group with 134 patients with residual diuresis > 500 mL.

RESULTS

Site- and type-specific cancers in our population of ESRD patients were all localized in estrogen-positive receptor organs. The increased risk of all types of urinary tract cancers occurred in the whole group, men and women, when compared to general population. There were a significantly higher number of patients with all types of cancers in the group with residual diuresis < 250 mL compared to patients with residual diuresis > 500 mL. Importantly, all urinary tract cancers were present in patients with residual diuresis < 500 mL.

CONCLUSION

Higher incidence of urinary tract cancers found in ESRD patients undergoing chronic hemodialysis is associated with lost residual diuresis. Residual diuresis in these patients might be considered a risk marker for future urinary tract cancers as well as already established markers.

Diseases and Syndromes That Affect the Lungs and the Kidneys: A Radiologic Review

A number of different conditions simultaneously affect both the lungs and the kidneys. These include autoimmune disorders and genetic tumor syndromes. Although manifestations within either organ system alone may not be specific, by observing the pattern of involvement and clinical history, radiologists may be able to suggest the correct diagnosis.

Percutaneous radiofrequency ablation with contrast-enhanced ultrasonography for solitary and sporadic renal cell carcinoma in patients with autosomal dominant polycystic kidney disease

Background

The aim of this study was to assess the functional and oncologic outcomes of percutaneous radiofrequency ablation (RFA) with contrast-enhanced ultrasonography (CEUS) for renal cell carcinoma in patient with autosomal dominant polycystic kidney.

Methods

We performed a retrospective review of five patients with renal cell carcinoma (RCC) in autosomal dominant polycystic kidney disease (ADPKD) from January 2009 to December 2014 with a media follow-up of 33 months. The tumors were ablated with Cool-tip RFA system under the guidance of CEUS. Routine follow-up included contrast-enhanced computed tomography/magnetic resonance imaging (CT/MRI) and renal function tests.

Results

Media diameter of the treated renal tumors was 3.1 cm (range 1.7–5.2 cm). Initial ablation success rate was 4/5. After over 6 months contrast-enhanced CT/MRI follow-up after RFA, no patients experienced local tumor recurrence. No patients required dialysis in the periprocedural period. Minor complications only developed in two cases. There was no significant difference in estimated glomerular filtration rate (eGFR) between pre- and post-RFA.

Conclusions

Our initial experience of this technique for RCC in ADPKD was favorable with good renal function preservation and oncologic outcomes. It may be a good choice for RCC in ADPKD.

Simultaneous Native Nephrectomy and Kidney Transplantation in Patients With Autosomal Dominant Polycystic Kidney Disease

Introduction

To evaluate the feasibility of simultaneous unilateral nephrectomy with kidney transplantation and to determine the effect of this procedure on perioperative morbidity and mortality and graft and patient survival.

Methods

Between January 2000 and May 2015, 145 patients with autosomal dominant polycystic kidney disease (ADPKD) underwent kidney transplantation. Of those, 40 (27.5%) underwent concurrent ipsilateral native nephrectomy (group NT). Patients in group NT were compared with patients with ADPKD not undergoing concurrent nephrectomy (group NT-) and asymptomatic patients undergoing pretransplant nephrectomy (group PNT).

Results

The average follow-up was 66 months. The graft survival rate at 1 and 5 years was 95% and 87.5% versus 93% and 76.2% in the NT and NT- groups, respectively (P = .903 and P = .544, respectively); 1-year patient survival was 100% for NT and 97% for NT- patients (P = .288), whereas 5-year patient survival was 100% and 92% for NT and NT- groups, respectively (P = .128). After propensity score matching (34 patients per group) no significant differences were observed in 1-year (97.1% in NT and 94.1%; P = 1) and 5-year (88.2% in NT and 91.2% in NT-; P = 1) graft survival, and in 1-year (100% for both groups; P = 1) and 5-year (100% in NT and 94.1% in NT-; P = 1) patient survival. Perioperative mortality was 0% among NT and 1.2% among NT- patients, whereas perioperative surgical complications were similar in both groups. One- and 5-year graft and patient survival were similar between the NT and PNT groups, but patients in the PNT group had significantly lower levels of hemoglobin and residual diuresis volumes at the time of transplant. Moreover, PNT patients had a longer pretransplant dialysis and a longer time on the waiting list.

Conclusions

Simultaneous unilateral nephrectomy does not have a negative effect on patient and graft survival in patients with ADPKD and is associated with low morbidity. Pretransplant nephrectomy should be restricted only to highly symptomatic patients, whereas unilateral nephrectomy in asymptomatic patients should be performed during kidney transplantation only if massive kidney size precludes graft positioning.

Inherited renal cystic diseases

A number of inherited renal diseases present with renal cysts and often lead to end-stage renal disease. With recent advances in genetics, increasing number of genes and mutations have been associated with cystic renal diseases. Although genetic testing can provide a definite diagnosis, it is often reserved for equivocal cases or for ongoing investigational research. Therefore, imaging findings are essential in the routine diagnosis, follow-up, and detection of complications in patients with inherited cystic renal diseases. In this article, the most recent classification, genetic analysis, clinical presentations, and imaging findings of inherited cystic renal diseases will be discussed.

Sorting the Alphabet Soup of Renal Pathology: A Review

Diseases of the kidney often have their names shortened, creating an arcane set of acronyms which can be confusing to both radiologists and clinicians. This review of renal pathology aims to explain some of the most commonly used acronyms within the field. For each entity, a summary of the clinical features, pathophysiology, and radiological findings is included to aid in the understanding and differentiation of these entities. Discussed topics include acute cortical necrosis, autosomal dominant polycystic kidney disease, angiomyolipoma, autosomal recessive polycystic kidney disease, acute tubular necrosis, localized cystic renal disease, multicystic dysplastic kidney, multilocular cystic nephroma, multilocular cystic renal cell carcinoma, medullary sponge kidney, paroxysmal nocturnal hemoglobinuria, renal papillary necrosis, transitional cell carcinoma, and xanthogranulomatous pyelonephritis.

Papillary renal cell carcinoma with a somatic mutation in MET in a patient with autosomal dominant polycystic kidney disease

Autosomal-dominant polycystic kidney disease (ADPKD) is caused by mutations in PKD1 and PKD2 and is characterized by proliferation of renal tubular epithelium and progressive chronic kidney disease. Derangements in similar cellular signaling pathways occur in ADPKD and renal malignancies, although an association of these disorders has not been established. Herein, we present a case of papillary RCC (pRCC) incidentally discovered in a patient with ADPKD following bilateral native nephrectomy during renal transplantation. Whole exome sequencing of the pRCC found a somatic missense mutation in MET proto-oncogene, p.Val1110Ile, not present in kidney cyst epithelium or non-cystic tissue. RNA sequencing demonstrated increased mRNA expression of MET and pathway-related genes, but no significant copy number variation of MET was detected. Genetic analysis of PKD genes from peripheral blood lymphocytes and renal cyst epithelium identified a constitutional PKD1 germline mutation, p.Trp1582Ser, predicted to be pathogenic. Unique somatic mutations in PKD1 were also detected in 80% of the renal cysts analyzed, but not in the pRCC. These results suggest that, in this patient, the pRCC utilized a signaling pathway involving MET that was distinct from the pathogenesis of ADPKD. This is the first report of PKD1 mutations and a somatic mutation of the MET oncogene in a pRCC in ADPKD.

The hallmarks of cancer: relevance to the pathogenesis of polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a progressive inherited disorder in which renal tissue is gradually replaced with fluid-filled cysts, giving rise to chronic kidney disease (CKD) and progressive loss of renal function. ADPKD is also associated with liver ductal cysts, hypertension, chronic pain and extra-renal problems such as cerebral aneurysms. Intriguingly, improved understanding of the signalling and pathological derangements characteristic of ADPKD has revealed marked similarities to those of solid tumours, even though the gross presentation of tumours and the greater morbidity and mortality associated with tumour invasion and metastasis would initially suggest entirely different disease processes. The commonalities between ADPKD and cancer are provocative, particularly in the context of recent preclinical and clinical studies of ADPKD that have shown promise with drugs that were originally developed for cancer. The potential therapeutic benefit of such repurposing has led us to review in detail the pathological features of ADPKD through the lens of the defined, classic hallmarks of cancer. In addition, we have evaluated features typical of ADPKD, and determined whether evidence supports the presence of such features in cancer cells. This analysis, which places pathological processes in the context of defined signalling pathways and approved signalling inhibitors, highlights potential avenues for further research and therapeutic exploitation in both diseases.

Renal cancer in kidney transplanted patients

Renal cancer occurs more frequently in renal transplanted patients than in the general population, affecting native kidneys in 90% of cases and the graft in 10 %. In addition to general risk factors, malignancy susceptibility may be influenced by immunosuppressive therapy, the use of calcineurin inhibitors (CNI) as compared with mammalian target of rapamycin inhibitors, and the length of dialysis treatment. Acquired cystic kidney disease may increase the risk for renal cancer after transplantation, while autosomal dominant polycystic kidney disease does not seem to predispose to cancer development. Annual ultrasound evaluation seems appropriate in patients with congenital or acquired cystic disease or even a single cyst in native kidneys, and every 2 years in patients older than 60 years if they were on dialysis for more than 5 years before transplantation. Immunosuppression should be lowered in patients who develop renal cancer, by reduction or withdrawal of CNI. Although more evidence is still needed, it seems reasonable to shift patients from CNI to everolimus or sirolimus if not already treated with one of these drugs, with due caution in subjects with chronic allograft nephropathy.

The Future of Polycystic Kidney Disease Research--As Seen By the 12 Kaplan Awardees

Polycystic kidney disease (PKD) is one of the most common life-threatening genetic diseases. Jared J. Grantham, M.D., has done more than any other individual to promote PKD research around the world. However, despite decades of investigation there is still no approved therapy for PKD in the United States. In May 2014, the University of Kansas Medical Center hosted a symposium in Kansas City honoring the occasion of Dr. Grantham's retirement and invited all the awardees of the Lillian Jean Kaplan International Prize for Advancement in the Understanding of Polycystic Kidney Disease to participate in a forward-thinking and interactive forum focused on future directions and innovations in PKD research. This article summarizes the contributions of the 12 Kaplan awardees and their vision for the future of PKD research.

Spanish guidelines for the management of autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent cause of genetic renal disease and accounts for 6-10% of patients on renal replacement therapy (RRT). Very few prospective, randomized trials or clinical studies address the diagnosis and management of this relatively frequent disorder. No clinical guidelines are available to date. This is a consensus statement presenting the recommendations of the Spanish Working Group on Inherited Kidney Diseases, which were agreed to following a literature search and discussions. Levels of evidence found were C and D according to the Centre for Evidence-Based Medicine (University of Oxford). The recommendations relate to, among other topics, the use of imaging and genetic diagnosis, management of hypertension, pain, cyst infections and bleeding, extra-renal involvement including polycystic liver disease and cranial aneurysms, management of chronic kidney disease (CKD) and RRT and management of children with ADPKD. Recommendations on specific ADPKD therapies are not provided since no drug has regulatory approval for this indication.

Renal relevant radiology: radiologic imaging in autosomal dominant polycystic kidney disease

Autosomal-dominant polycystic kidney disease is a systemic disorder and the most common hereditary renal disease, which is characterized by cyst growth, progressive renal enlargement, and development of renal failure. The cystic nature of autosomal dominant polycystic kidney disease and its renal and extrarenal complications (kidney stones, cyst hemorrhage, intracerebral aneurysm, liver cysts, cardiac valve abnormalities, etc.) give radiologic imaging studies a central role in the management of these patients. This article reviews the indications, comparative use, and limitation of various imaging modalities (ultrasonography, magnetic resonance imaging, computerized tomography scan, Positron emission tomography scan, and renal scintigraphy) for the diagnosis and management of complications in autosomal dominant polycystic kidney disease. Finally, this work provides evidence for the value of total kidney volume to predict disease progression in autosomal dominant polycystic kidney disease.

Risk factors for renal cell carcinoma in the VITAL study

PURPOSE

The incidence of renal cell carcinoma is increasing worldwide. Cited risk factors include obesity, smoking and hypertension but few others have been confirmed in prospective studies. We used a prospective cohort to validate established renal cell carcinoma risk factors and evaluate more controversial risk factors for incident renal cell carcinoma.

MATERIALS AND METHODS

A total of 77,260 residents of Washington 50 to 76 years old completed a questionnaire between 2000 and 2002 on demographic, lifestyle and health data. Incident renal cell carcinoma cases were determined by linkage to the regional cancer registry through December 31, 2009. Multivariate methods using covariates and cutoffs selected a priori were applied to analyze the association between renal cell carcinoma and previously studied factors related to lifestyle (body mass index, smoking and alcohol/fruit/vegetable consumption) and health (hypertension, diabetes, kidney disease and viral hepatitis).

RESULTS

There were 249 incident cases of renal cell carcinoma. Independent renal cell carcinoma risk factors in the fully adjusted model were body mass index (35 or greater vs less than 25 kg/m2 HR 1.71, 95% CI 1.06-2.79), smoking (greater than 37.5 pack-years vs never HR 1.58, 95% CI 1.09-2.29), hypertension (HR 1.70, 95% CI 1.30-2.22), kidney disease (HR 2.58, 95% CI 1.21-5.50) and viral hepatitis (HR 1.80, 95% CI 1.03-3.14). Diabetes was associated with renal cell carcinoma (HR 1.83, 95% CI 1.26-2.65) in a base model adjusting for age and gender but not in the multivariate model. We found no association between alcohol, fruit or vegetable intake and renal cell carcinoma.

CONCLUSIONS

We identified a significant association of renal cell carcinoma with obesity, smoking, hypertension, renal disease and viral hepatitis. Identifying risk factors offers an opportunity for targeted education and intervention.

Kidney transplantation with and without simultaneous bilateral native nephrectomy in patients with polycystic kidney disease: a comparative retrospective study

BACKGROUND

Patients with autosomal dominant polycystic kidney disease (ADPKD) often need to undergo native nephrectomy and are candidates for kidney transplantation. The necessity and timing of nephrectomy are controversial. Some authors recommend simultaneous bilateral native nephrectomy (SBN) as the preferred option in living-donor kidney transplantation (LDKT). These recommendations are based on small study populations. We therefore set out to study outcomes of LDKT with SBN, compared with LDKT alone in a larger single-center cohort.

METHODS

A consecutive series of 159 patients with ADPKD undergoing LDKT were included in the study. Of the 159 patients, 2 were excluded because of missing data, 79 underwent LDKT alone (group A), and 78 underwent LDKT with SBN (group B). Demographic data and intraoperative and postoperative data were collected from patient charts and the national kidney registry.

RESULTS

There were no differences regarding background data. Group B experienced significantly longer operating times (183.7 vs. 319.3 min, P<0.001), a greater need for blood transfusions (0.1 vs. 1.6 units, P<0.001) and plasma products (35.1 vs. 438.3 mL, P<0.001), and longer hospital stays (11.8 vs. 15.4 days, P<0.001). It also experienced more intraoperative events and postoperative complications but fewer reoperations/reinterventions. There were no differences in patient and graft survival rates.

CONCLUSIONS

SBN in patients undergoing LDKT for ADPKD does not have a significant negative impact on patient and graft survival rates. It obviates a separate surgical procedure but requires longer hospital stay. It may be associated with more postoperative complications and risk of graft loss. These considerations should be communicated to the recipient and the donor.

Multifocal renal cell carcinoma of different histological subtypes in autosomal dominant polycystic kidney disease

Renal cell carcinoma (RCC) in autosomal dominant polycystic kidney (ADPKD) is rare. To date, 54 cases of RCC in ADPKD have been reported. Among these, only 2 cases have different histologic types of RCC. Here we describe a 45-year-old man who received radical nephrectomy for multifocal RCC with synchronous papillary and clear cell histology in ADPKD and chronic renal failure under regular hemodialysis. The case reported herein is another example of the rare pathological finding of RCC arising in a patient with ADPKD.