ACQUIRED CYSTIC KIDNEY DISEASE

Acquired cystic kidney disease in children with kidney failure

BACKGROUND

This study aimed to evaluate the incidence, contributing factors, and clinical outcomes of acquired cystic kidney disease (ACKD) in children undergoing kidney replacement therapy (KRT).

METHODS

We conducted a cross-sectional, territory-wide study at the designated pediatric nephrology center in Hong Kong. ACKD was defined as the presence of ≥ 3 cysts in the native kidneys, excluding congenital or hereditary cystic diseases. Between June to December 2023, all paediatric patients receiving KRT in Hong Kong underwent ultrasonography, non-contrast magnetic resonance imaging (MRI), or both. Contrast-enhanced computed tomography was performed for patients with complex cysts.

RESULTS

Forty-three children (56% female; median age 14.7 years; IQR, 11.7-18.7) were included in the analysis. ACKD was detected in 18 children (42%). Nine subjects had complex cysts (grade 2, n = 5; grade 2F, n = 2; grade 3, n = 2). Most patients with ACKD (89%) were asymptomatic. One patient (5.5%) developed back pain and gross haematuria 72 months after initiation of KRT. Another patient (5.5%) developed infected cyst with back pain and clinical sepsis 60 months following KRT initiation. A dialysis duration of ≥ 28 months was the only significant factor associated with ACKD development (77.8% vs. 40%; p = 0.028; ORadj 6.09, 95% CI 1.43-25.82, p = 0.014). The diagnostic yield of paired ultrasound and MRI was superior to ultrasound alone.

CONCLUSIONS

ACKD is prevalent among children and adolescents with kidney failure, with most cases being asymptomatic, however serious complications may arise. Longer duration of dialysis is significantly associated with ACKD development. Therefore, early transplantation and active ACKD surveillance are crucial for children receiving KRT.

A Case of Acquired Cystic Kidney Disease From Chronic Renal Failure Without Dialysis

The kidneys play a vital role in maintaining homeostasis by filtering the blood of waste products and toxins, maintaining a delicate balance of fluids and electrolytes, and closely regulating blood pressure via the juxtaglomerular apparatus. Cystic kidney disease is a pathology of the kidneys that can be either acquired or congenital. This case report introduces a seventy-eight-year-old male with a medical history of a myocardial infarction and heart valve replacements who presented to the emergency department due to a recent fall at home unrelated to syncope. As he rose from his chair, the patient fell forward but was able to pick himself up from the ground. Upon further review, lab work revealed end-stage renal disease with a creatinine of 19.7 mg/dL (reference range: 0.6-1.2 mg/dL) and blood urea nitrogen of 186 mg/dL (reference range: 7-18 mg/dL). Potassium was 5.2 mmol/L (reference range: 3.5-5.1 mmol/L) and the electrocardiogram showed normal sinus rhythm. Urinalysis showed proteinuria of 100 mg/dL with high white blood cells 28/High-power field and red blood cells (RBCs) 3/HPF but no bacteria. Trace blood and leukocyte esterase were also noted. Microscopic analysis was significant only for epithelial cells 1/HPF. The patient also had symptomatic anemia with a hemoglobin of 6.4 g/dL, which contributed to his symptoms on presentation. Computed tomography of the abdomen and pelvis without intravenous or per oral contrast revealed numerous bilateral renal parenchymal cysts. After receiving two units of packed RBCs for severe anemia, he underwent several dialysis treatments during his stay. The patient denied a family history of polycystic kidney disease, though he had a deceased sister with unspecified "kidney problems." Acquired cystic kidney disease (ACKD) before dialysis is a rare phenomenon that prompts a careful history, physical exam, and diagnostic evaluation to avoid misdiagnosis and improper treatment. Although rare and not cited often in the literature, ACKD should be entertained in the differential diagnosis of this presentation.

Cystic Kidney Diseases in Children and Adults: Differences and Gaps in Clinical Management

Cystic kidney diseases, when broadly defined, have a wide differential diagnosis extending from recessive diseases with a prenatal or pediatric diagnosis, to the most common autosomal-dominant polycystic kidney disease primarily affecting adults, and several other genetic or acquired etiologies that can manifest with kidney cysts. The most likely diagnoses to consider when assessing a patient with cystic kidney disease differ depending on family history, age stratum, radiologic characteristics, and extrarenal features. Accurate identification of the underlying condition is crucial to estimate the prognosis and initiate the appropriate management, identification of extrarenal manifestations, and counseling on recurrence risk in future pregnancies. There are significant differences in the clinical approach to investigating and managing kidney cysts in children compared with adults. Next-generation sequencing has revolutionized the diagnosis of inherited disorders of the kidney, despite limitations in access and challenges in interpreting the data. Disease-modifying treatments are lacking in the majority of kidney cystic diseases. For adults with rapid progressive autosomal-dominant polycystic kidney disease, tolvaptan (V2-receptor antagonist) has been approved to slow the rate of decline in kidney function. In this article, we examine the differences in the differential diagnosis and clinical management of cystic kidney disease in children versus adults, and we highlight the progress in molecular diagnostics and therapeutics, as well as some of the gaps meriting further attention.

Genomic features of renal cell carcinoma developed during end-stage renal disease and dialysis

Patients with end-stage renal disease (ESRD) or receiving dialysis have a much higher risk for renal cell carcinoma (RCC), but carcinogenic mechanisms and genomic features remain little explored and undefined. This study's goal was to identify the genomic features of ESRD RCC and characterize them for associations with tumor histology and dialysis exposure. In this study, we obtained 33 RCCs, with various histological subtypes, that developed in ESRD patients receiving dialysis and performed whole-genome sequencing and transcriptome analyses. Driver events, copy-number alteration (CNA) analysis and mutational signature profiling were performed using an analysis pipeline that integrated data from germline and somatic SNVs, Indels and structural variants as well as CNAs, while transcriptome data were analyzed for differentially expressed genes and through gene set enrichment analysis. ESRD related clear cell RCCs' driver genes and mutations mirrored those in sporadic ccRCCs. Longer dialysis periods significantly correlated with a rare mutational signature SBS23, whose etiology is unknown, and increased mitochondrial copy number. All acquired cystic disease (ACD)-RCCs, which developed specifically in ESRD patients, showed chromosome 16q amplification. Gene expression analysis suggests similarity between certain ACD-RCCs and papillary RCCs and in TCGA papillary RCCs with chromosome 16 gain identified enrichment for genes related to DNA repair, as well as pathways related to reactive oxygen species, oxidative phosphorylation and targets of Myc. This analysis suggests that ESRD or dialysis could induce types of cellular stress that impact some specific types of genomic damage leading to oncogenesis.

Acquired cystic disease-associated renal cell carcinoma is the most common subtype in long-term dialyzed patients: Central pathology results according to the 2016 WHO classification in a multi-institutional study

New pathological subtypes of renal cell carcinoma (RCC) were designated in the 2016 World Health Organization (WHO) classification corresponding to the features commonly seen in patients with end-stage renal disease (ESRD). To determine the clinicopathological findings of new subtypes, we reanalyzed all sections from 315 kidneys in 291 ESRD patients bearing RCC tumors surgically resected in three Japanese institutes by the central pathologist. Clear cell RCC was diagnosed in 144 kidneys (45.7%), acquired cystic disease (ACD)-associated RCC in 100 (31.7%), papillary RCC in 41 (13.0%), and other minor subtypes in 30 (9.52%). Multivariate analysis showed that longer duration of dialysis, young age, and male sex were independent prognostic clinical factors for the occurrence of ACD-associated RCC. ACD-associated RCC included more WHO/International Society of Urologic Pathology (ISUP) grade 3/4 cases compared to other RCCs. In contrast, other unfavorable findings were less frequent in ACD-associated RCC, including the presence of a sarcomatoid component, lymphovascular invasion, and necrosis. In conclusion, ACD-associated RCC is a common histology in Japanese patients with ESRD. In addition, ACD-associated RCC showed more cases with a higher WHO/ISUP grade, but fewer cases with other unfavorable pathological features, suggesting a favorable prognosis of ACD-associated RCC.