Segmental multicystic dysplastic kidney in children

Pediatric segmental multicystic dysplastic kidney is a rare subtype of multicystic dysplastic kidney disease, with only 18 case reports published. All children previously reported with this condition presented during infancy. This is the first case of segmental multicystic dysplastic kidney in an adolescent girl. The case is discussed, along with a review of published reports.     

WILMS TUMOR AND MULTICYSTIC DYSPLASTIC KIDNEY DISEASE

Purpose

There is ongoing controversy concerning the management of multicystic dysplastic kidney disease, particularly with regard to the potential for malignant transformation. Our report fuels the debate by adding the 2 youngest patients in whom malignancy was present from birth or developed subsequently.

Materials and Methods

Two well documented cases of malignancy associated with multicystic dysplastic kidney disease are presented in 2 female infants (5 and 3 months old). The 5-month-old female infant was followed for multicystic dysplastic kidney disease and had no evidence of tumor either antenatally or at birth. The 3-month-old presented with hypertension and interventricular septal defect. A renal tumor was present on initial ultrasound.

Results

Even though malignant degeneration is rare in multicystic dysplastic kidney disease, 9 cases have been reported in the literature so far. Of these cases 3 were Wilms tumor, 5 were renal cell carcinomas and 1 mesothelioma.

Conclusions

Our 2 cases lend support to the surgical management of multicystic dysplastic kidney disease, particularly as nephrectomy can now be performed in a day surgery setting with minimal morbidity. Only the risks of coexisting malignancy and possible malignant degeneration transformation are specifically addressed in this article. Other complications of multicystic dysplastic kidney disease such as hypertension, infection, abdominal pain, hematuria and persistent dysplastic renal tissue despite ultrasonographic resolution of multicystic dysplastic kidney disease are additional risk factors to be considered. A recommendation for nephrectomy in all cases of multicystic dysplastic kidney disease cannot be based only on these 2 cases. Several other factors must be weighed before making that decision.     

Dysplastic kidney and not renal agenesis is the commonly associated anomaly in infants with seminal vesicle cyst

OBJECTIVE

To determine whether the association of seminal vesicle cyst (SVC) and renal anomaly in young children correlates with previously reported cases of SVCs in adolescent and adult patients, as congenital SVCs, although rare, are frequently described in association with ipsilateral renal agenesis, mainly in adolescent and adult patients, whereas reports on SVCs in younger children are sparse.

PATIENTS AND METHODS

We report on nine infants (median age 4 months) with congenital SVCs, all of them associated with ipsilateral dysplastic kidneys. All patients had ultrasonography of the renal system and voiding cysto‐urethrography. Magnetic resonance imaging was used in two patients.

RESULTS

The SVCs were found incidentally during ultrasonography for the renal anomaly. Three patients had dysplastic and six had multicystic dysplastic kidneys. In previous reported adult cases of SVCs the most common associated renal anomaly was agenesis of the ipsilateral kidney (25 of 44 cases), whereas only one case of dysplastic kidney was reported.

CONCLUSION

As the appearance of renal agenesis might result from a former congenital dysplastic kidney, our findings indicate that cases of ipsilateral renal agenesis in adult patients with congenital SVCs might represent former dysplastic or multicystic dysplastic kidney.     

先天性小肾脏单输尿管异位开口的诊断与治疗（附七例报告）

报告７例先天性小肾脏单输尿管异位开口的诊断与治疗。７例均为女性，年龄３．２～１４．０岁，６例异位开口于阴道，１例开口于尿道。Ｂ超、ＩＶＵ均误诊为先天性孤肾，３例作ＣＴ检查仅１例发现囊样变小肾脏，ＣＤＩ检查４例均获确诊，７例均行发育不良肾切除而治愈。对其发病情况、胚胎发生学、诊断与治疗进行了讨论，认为ＣＤＩ是诊断重要手段，对发育不良小肾脏者肾切除为首选治疗。     

Neonatal hypertension from a unilateral multicystic dysplastic kidney

Multicystic renal dysplasia is an extremely uncommon cause of hypertension in children and the few reported cases have not been of newborns. We report on a neonate in whom severe hypertension associated with elevated peripheral plasma renin resulted from a unilateral multicystic dysplastic kidney. Hypertension and plasma renin activity normalized after unilateral nephrectomy. No evidence of perfusion or excretory renal function in the dysplastic kidney was present on a radionuclide renal scan. This child demonstrates a relationship between hypertension and unilateral multicystic renal dysplasia.     

Ectopic single ureter and severe renal dysplasia: an unusual presentation.

An ectopic single ureter in the male subject is a rare anomaly, which commonly drains a dysplastic kidney to the prostatic urethra or the seminal vesicle. The further the ureteral orifice is located from the trigone of the bladder, the more severe is the ipsilateral renal dysplasia. A case is described in which an ectopic ureter and ectopic and dysplastic kidney were found at the time of inguinal herniorrhaphy. The ureter was connected to the epididymis of the testicle. This is the most severe form of ureteral ectopia and it has not been reported previously.     

Laparoscopic nephroureterectomy for adult incontinence caused by functioning ectopic pelvic kidney draining into vagina

A 29-year-old woman had been continent of the majority of her urine for her entire life but had constant, uncontrollable dribbling. A contrast CT scan showed a solitary functioning left kidney and a dysplastic right pelvic kidney with a tortuous dilated ureter running close to the vaginal vault. The kidney was removed whole at transperitoneal laparoscopy, rendering the patient continent. This is the first such case reported in an adult.     

Malignant retroperitoneal tumor arising in a multicystic dysplastic kidney of a girl with Schinzel–Giedion syndrome

We report the first case of malignant retroperitoneal tumor arising in a multicystic dysplastic kidney of an 8-year-old girl with Schinzel-Giedion syndrome. Although conservative treatment has been regarded as the standard management for asymptomatic multicystic dysplastic kidney, prophylactic surgical removal should be considered for selected children with potential risk of malignancy.     

Multicystic dysplastic kidney associated with Waardenburg syndrome type 1

 A 16-day-old girl with Waardenburg syndrome type 1 presented with a right multicystic dysplastic kidney (MDK) and hydronephrosis in the left kidney. To our knowledge, such an association has not yet been reported and should be added to the list of MDK-associated genetic syndromes. Received November 15, 1996; received in revised form and accepted April 1, 1997     

Increased c-Met tyrosine kinase expression in segmental renal dysplasia

Renal dysplasia (RD) is a disorganized development of renal parenchyma that results in a deficit of functional renal tissue. It has been suggested in the animal model that increased expression of HGF receptor, c-Met tyrosine kinase in the epithelial cells during kidney development may induce a growth of dysplastic epithelia and result in RD. The aim of this study was to investigate the immunoreactivity of c-Met tyrosine kinase in the dysplastic kidney in order to further understand the pathogenesis of RD. Specimens of dysplastic upper pole kidney were obtained from 19 patients during upper pole partial nephrectomy for non-functioning upper moiety of duplex kidney. In the dysplastic kidney, there was strong c-Met immunoreactivity in the epithelium of primitive tubules. In contrast, c-Met immunoreactivity was barely detectable in the normal kidney. Markedly increased expression of HGF receptor, c-Met tyrosine kinase in renal dysplasia suggests that HGF may be involved in the development of renal dysplasia.     

Hydronephrotic obstructed kidney mimicking a congenital multicystic kidney: Case report with review of literature

Objective: To report a case of obstructed hydronephrotic kidney mimicking a multicystic kidney and to review the literature regarding differentiation of the hydronephrotic variant of multicystic kidney from the obstructed hydronephronic kidney. To suggest a possible algorithm in distinguishing them.Methods:We have reported a case of a 35-year-old male who presented with dull aching pain and a palpable right-sided cystic flank mass of several years duration. The initial workup suggested a nonfunctioning multicystic kidney while the operative findings and histopathology were suggestive of an obstructed hydroenphrotic kidney with pyelonephritic changes. We searched the literature using the key words hydronephrotic dysplastic kidney and multicystic kidney.Results:A detailed literature search did not reveal any such publication describing the differentiation of the hydronephrotic multicystic dysplastic kidney from the obstructed hydronephrotic kidney of pelviureteral obstruction. We reviewed the existing literature on this subject, on the basis of which, we have suggested a six-stepladder approach to distinguish such cases.Conclusion:By using the 6 step ladder protocol algorithm suggested by us one can attempt to distinguish the hydronephrotic variant of multicystic dysplastic kidney from the hydronephrotic kidney due to pelviureteral obstruction in patients presenting with a symptomatic cystic flank masses of renal origin. Differentiation between the two may be difficult at times due to the medial/central placement of cysts in the former. This is necessary since renal salvage may be possible in the latter while timely nephrectomy may be considered in the former to prevent against the hazards of leaving behind a dysplastic kidney in situ.     

Squamous cysts arising from segmental renal dysplasia

Background  

Cystic renal dysplasia is a common developmental abnormality of fetal kidney, featuring disorganized lobar organization, undifferentiated mesenchyma, metaplastic cartilage, persisting immature collecting ducts, and cystic changes. Cystic renal dysplasia can affect the entire kidney or in a segmental fashion. Squamous cysts within the dysplastic kidney, however, are exceedingly rare; only two cases have been reported in the English literature, dating back about 25 years.     

Laparoscopic nephrectomy for renovascular hypertension in a 6-month-old infant.

Laparoscopic procedures continue to gain popularity over traditional open operations for a variety of abdominal and retroperitoneal surgical procedures. With regard to urological surgery, the first laparoscopic nephrectomy was performed in an adult in 1991. In the following years, the feasibility of laparoscopic management of pediatric urological disorders was described, and in 1992 the first laparoscopic nephrectomy in an 8-month-old infant with a multicystic dysplastic kidney was reported. We report the feasibility of laparoscopic nephrectomy for the management of renovascular hypertension in a 6-month-old infant with a dysplastic left kidney.     

Expression of mitogen-activated protein kinases in human renal dysplasia

BACKGROUND: We previously reported that the expression of mitogen-activated protein kinases (MAPKs) is developmentally regulated. Dysregulation of MAPKs may lead to kidney malformation. Thus, we investigated the expression of MAPKs in human renal dysplasia, one of the most common kidney malformations. METHODS: Prenatal (gestational ages 20 to 36 weeks, N = 6) and postnatal (2 years old, N = 1) dysplastic kidneys, and normal kidneys (gestational ages 19 to 34 weeks, N = 4) were examined. Immunohistochemical studies were performed using antibodies against extracellular signal-regulated kinase (ERK), p38 MAPK (p38), c-Jun N-terminal kinase (JNK), phospho-MAPKs (P-MAPKs), and proliferating cell nuclear antigen (PCNA). Apoptosis was detected by the TUNEL method. RESULTS: In dysplastic kidneys, proliferation was prominent in dysplastic tubules and also found in cyst epithelia. TUNEL staining was detected in dysplastic tubules and cysts, and occasionally in undifferentiated cells. p38 and anti-phospho-p38 (P-p38) were strongly expressed in dysplastic epithelia, but not detected in normal kidneys at any stage examined. On the other hand, JNK and P-JNK were positive in tubular epithelia of normal kidneys, whereas their expression was barely detectable in dysplastic tubules and cysts. ERK was expressed in all tubular segments, and P-ERK was detected in distal tubules and collecting ducts of normal kidneys. Dysplastic kidney epithelia stained exclusively positive for ERK and P-ERK. CONCLUSIONS: p38 is ectopically expressed, and JNK is down-regulated in dysplastic kidney epithelia. Furthermore, dysplastic epithelia are exclusively positive for ERK and P-ERK. Activated p38 and ERK may mediate hyperproliferation of dysplastic tubules resulting in cyst formation, whereas down-regulated JNK expression may be the cause or the result of an undifferentiated state of dysplastic epithelia.     

Multicystic dysplastic kidney and variable phenotype in a family with a novel deletion mutation of PAX2

The renal coloboma syndrome (OMIM 120330) is caused by mutations in the PAX2 gene. Typical findings in these patients include renal hypoplasia, renal insufficiency, vesicoureteric reflux, and optic disc coloboma. A family with a novel heterozygous 10-bp deletion in exon 2 of the PAX2 gene leading to a truncating mutation and variable phenotype across three generations is reported. The first presentation of multicystic dysplastic kidney in this syndrome is reported. The possibility that abnormal PAX2 protein in this case may cause a dominant negative effect also is discussed. The finding of multicystic dysplastic kidney in renal coloboma syndrome could suggest that PAX2 may play a role in early ureteric obstruction and subsequent renal maldevelopment.     

Renin containing cells are present predominantly in scarred areas but not in dysplastic regions in multicystic dysplastic kidney

PURPOSE: Hypertension is an important complication of multicystic dysplastic kidney and it has been suggested that it is induced by renin. Little information is available on renin production in this disease. To assess renin production we examined the distribution of renin containing cells in multicystic dysplastic kidneys using immunohistochemical methods. MATERIALS AND METHODS: Immunohistochemical examination of renin was performed in 29 multicystic dysplastic kidneys from 14 boys and 15 girls 1 month to 10 years old using rabbit anti-human renin antibodies. In all cases normal renal function was confirmed by the serum creatinine level and no proteinuria on urinalysis. Two patients had the complication of hypertension before removal of the multicystic dysplastic kidney but plasma renin activity was normal. RESULTS: Immunostaining of renin was observed in 26 of 29 multicystic dysplastic kidneys (90%). Histologically multicystic dysplastic kidney involved scarred and dysplastic areas. Renin positive cells were observed predominantly in the scarred areas, mainly in the juxtaglomerular apparatus of mature glomeruli, interlobular arteries and some mature tubules. Immunopositive renin was sparsely noted in the juxtaglomerular apparatus or Bowman's capsules of occasional immature glomeruli in dysplastic areas. CONCLUSIONS: Our observations suggest that multicystic dysplastic kidney may have the ability to produce renin. Renin producing cells in the juxtaglomerular apparatus of mature glomeruli and interlobular arteries in the scarred areas may be the predominant source of renin production in this organ.     

Transitional cell carcinoma in a single ectopic ureter opening into the ejaculatory duct

The incidence of an ectopic ureter in male patients is low. The ectopic ureter in men often ends at the seminal tract in association with renal dysgenesis. Malignant transformation of this closed, nonfunctional urothelial system has been reported only once. To our knowledge, we report the first case of primary transitional cell carcinoma in a single ectopic ureter with a dysplastic kidney that terminated in the ejaculatory duct.     

Laparoscopic nephrectomy for a single-system ectopic ureter draining a small, dysplastic and poorly functioning kidney in children

PURPOSES: To assess the efficacy of laparoscopic nephrectomy for a single-system ectopic ureter draining a dysplastic kidney in children. PATIENTS AND METHODS: Between February 1999 and September 2005, 16 girls with a mean age of 6.2 years (range: 2-15 years) presented with urinary incontinence accompanied by regular voiding since birth (15 patients) and vaginitis (one patient). Ultrasonography, intravenous urography and a 99mTc-DMSA renal scan showed the presence of only a single kidney in all cases. Computed tomography (CT) showed a dysplastic kidney definitely in nine patients, structures suspicious of dysplastic kidney in three cases, and no dysplastic kidney in four cases. Magnetic resonance imaging was carried out in the four cases with non-visualized dysplastic kidneys by CT, and showed a suspicious lesion in only one case, and no lesion in the other three patients. All patients underwent transperitoneal laparoscopic nephrectomy for a dysplastic kidney. RESULTS: Laparoscopy identifies all dysplastic kidneys easily, even in those cases in which dystrophic kidney could not be identified by preoperative imaging. Dysplastic kidneys and ectopic ureters were removed successfully in all 16 patients. Mean operative time was 109 min (range: 40-155 min) with little intraoperative bleeding. Mean postoperative hospital stay was 2.6 days (range: 2-4 days). No intraoperative complication was encountered, except in one single case, in which a small bowel injury occurred during open Hasson's procedure. All patients became dry soon after the operation. CONCLUSION: Laparoscopic nephrectomy for an ectopic ureter draining into a dysplastic kidney is a safe and effective method, and can be carried out successfully, despite a failure by preoperative imaging studies to localize the dysplastic kidney.     

Single ectopic vaginal ureter diagnosed by computed tomography

A case of a single ectopic vaginal ureter in a 6-year-old girl with urinary incontinence is reported. Excretory urography and renal sonography failed to visualize the dysplastic kidney, but enhanced computed tomography clearly demonstrated a poorly functioning hypoplastic kidney, ectopic ureter and vagina filled with contrast medium. Copyright Copyright 1999 S. Karger AG, Basel     

Multicystic dysplastic kidney: natural history from in utero diagnosis and postnatal followup

Based on our experience with 13 in utero diagnoses we report the changes that may occur in the ultrasonic appearance of a multicystic dysplastic kidney. Macrocysts appear obvious only in the early third trimester of pregnancy. After reaching a maximum size the cysts start to involute either in utero or after birth, which may lead to a small noncystic mass, the so-called aplastic kidney, or even to complete disappearance of the entire dysplastic kidney. The dysplastic kidney seems vulnerable to anoxia or infection, and necrosis may supervene. The multicystic dysplastic kidney is a progressive and changing disorder. If its radiological appearance is typical management may be conservative with ultrasonic monitoring. Nephrectomy should be done if there is any abnormal clinical or ultrasonic change.