Unilateral and segmental cystic disease of the kidney

Cystic Kidney Diseases That Require a Differential Diagnosis from Autosomal Dominant Polycystic Kidney Disease (ADPKD)

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary cystic kidney disease, with patients often having a positive family history that is characterized by a similar phenotype. However, in atypical cases, particularly those in which family history is unclear, a differential diagnosis between ADPKD and other cystic kidney diseases is important. When diagnosing ADPKD, cystic kidney diseases that can easily be excluded using clinical information include: multiple simple renal cysts, acquired cystic kidney disease (ACKD), multilocular renal cyst/multilocular cystic nephroma/polycystic nephroma, multicystic kidney/multicystic dysplastic kidney (MCDK), and unilateral renal cystic disease (URCD). However, there are other cystic kidney diseases that usually require genetic testing, or another means of supplementing clinical information to enable a differential diagnosis of ADPKD. These include autosomal recessive polycystic kidney disease (ARPKD), autosomal dominant tubulointerstitial kidney disease (ADTKD), nephronophthisis (NPH), oral-facial-digital (OFD) syndrome type 1, and neoplastic cystic kidney disease, such as tuberous sclerosis (TSC) and Von Hippel-Lindau (VHL) syndrome. To help physicians evaluate cystic kidney diseases, this article provides a review of cystic kidney diseases for which a differential diagnosis is required for ADPKD.

Identifying gene mutations of Chinese patients with polycystic kidney disease through targeted next-generation sequencing technology

BACKGROUND

Polycystic kidney disease (PKD) is the most common hereditary kidney disease. The main mutational genes causing autosomal dominant polycystic kidney disease (ADPKD) are PKD1 and PKD2 as well as some rare pathogenic genes. Unilateral PKD is rare in clinics, and its association with gene mutations is unclear.

METHODS

Targeted next-generation sequencing (NGS) was performed to detect the renal ciliopathy-associated genes (targeted NGS panel including 63 genes) in PKD patients.

RESULTS

Forty-eight PKD1 and PKD2 mutation sites were detected in 44 bilateral PKD patients, of which 48 were PKD1 mutation sites (87.5%) and six were PKD2 mutation sites (12.5%). All of which exhibited typical ADPKD. Furthermore, we detected HNF1B heterozygous mutations in three families. Although these three patients showed HNF1B heterozygous mutations, their clinical characteristics differed and showed phenotypic heterogeneity.

CONCLUSIONS

Targeted NGS panel was helpful in detecting typical ADPKD patients and even in non-typical PKD patients. Macromutation in HNF1B may lead to bilateral PKD. The 16 novel PKD gene mutation sites and two novel PKD2 gene mutation sites discovered in this study have some significance in genetic counseling for ADPKD patients, and increase the number of studied families and expand the mutation database of ADPKD.

Disparate Presentations of Localized Cystic Disease of Kidney: A Review with an Objective of Correct Approach for Accurate Treatment Plan

Background

Localized cystic disease of the kidney is a rare, non-familial condition. Its imaging and clinical features are unique and need to be differentiated from autosomal dominant polycystic kidney disease and focal cystic masses such as multicystic nephroma and cystic renal cell carcinoma. It is always restricted to one kidney and is characterized by multiple cysts of varying sizes separated by residual normal renal tissue.

Materials and methods

This study reports 12 cases of localized cystic disease of the kidney based on imaging findings and clinical histories. The modalities of choice were ultrasonography followed by contrast-enhanced computed tomography. Eight out of 12 patients were men and the average age of presentation was 46 years. The screening of family members and relatives was done to rule out the differentials.

Results

Localized cystic disease of kidney was diagnosed in all the patients and it presented in two different forms. In three patients, multiple cysts involved whole of the kidney, resulting in thinned-out residual renal parenchyma. In the rest nine patients it remained localised to a particular segment of the kidney. No cysts were observed in the contralateral kidney in seven patients, and one or two simple cysts were observed in five. Clinical presentations included only flank pain in six patients, flank pain with palpable abdominal mass in four patients, two patients presented as asymptomatic cases with diagnosis as an incidental finding and one patient with hematuria. Eight patients underwent imaging and two underwent clinical follow-up for a period of two years showing stability of the disease. One patient underwent nephrectomy for suspected renal neoplasm.

Conclusion

Localized cystic disease of the kidney is a unilateral, rare and stable disease that has two different forms of presentations. Its imaging findings should be clearly understood so as to not classify it as a separate disease and avoid unnecessary surgery. It rarely leads to hypertension or polycythemia, and until then no definitive management is required. It can be followed up using imaging techniques and requires nephrectomy only when the suspicion of malignancy is strong.

Localized cystic disease of the kidney: a rare entity

Localized cystic disease of the kidney is a benign nonsurgical entity and presents with multiple cystic lesions in just one portion of the kidney or involves the entire one kidney. We report a case of localized cystic disease of the kidney in a 16 year-old-male. This patient underwent an ultrasound examination and incidentally found to have multiple cysts in the right kidney whereas the left kidney was normal. Diagnosis was confirmed by typical MRI findings, absence of any family history, normal results of urine analysis and renal function tests.

Segmental cystic renal disease: sonographic and CT findings

Segmental cystic renal disease is a unique benign condition that requires no treatment. It can be confused on imaging, especially on sonography, with other more common cystic renal diseases and sometimes cystic malignancy. We report a case of segmental cystic renal disease with typical imaging features on sonography and CT for which nephrectomy was avoided.