Wilms' tumor arising in a multicystic kidney

Prof. Dr. Giovanni De Toni-Editorial for the Commemoration of a Pediatric Luminary

Living in Liguria, acknowledging that the sea may be a metaphor for the human condition is not difficult [...].

Exposure to pesticides and pediatric Wilms' tumor. A meta-analysis on pre-conception and pregnancy parental exposure with an IARC/WHO commentary

BACKGROUND

There are hereditary types of nephroblastoma or Wilms' tumor associated with exposure of the germ cells of either parent to harmful environmental factors. Some studies have examined the exposure of compounds used pesticides and herbicides as a risk factor for Wilms' tumor.

METHODS

A systematic review and meta-analysis were carried out on case-control studies to establish the potential link between exposure to these organic molecules and Wilms' tumor occurrence in children rigorously. We examined the monographs on some organo-phosphate insecticides and herbicides issued by the International Association for the Research on Cancer (IARC) under the auspices of the World Health Organization (WHO). PUBMED, SCOPUS, and Google Scholar studies (1960-2021) were identified and systematically reviewed following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Subgroup analyses were conducted after stratification for occupational versus residential exposure and before birth (prenatal) vs. after birth (postnatal) exposure. In addition, we revised the monographs on chemical compounds issued recently by the IARC/WHO.

RESULTS

Our findings seem to consolidate that parental pesticide exposure during the preconception or pregnancy period is correlated with an increased occurrence risk for Wilms' tumor. We confirm the validity of the WHO essays on certain organophosphate herbicides and insecticides, which support these compounds, may be highly relevant in future cancer prevention policies.

CONCLUSION

Parental exposure to pesticides, particularly in household settings, is poorly emphasized in our society. There is a strong association between these organophosphate compounds and pediatric cancer. Public health agencies may need to take stronger action than in the past.

Evidence-based treatment of multicystic dysplastic kidney: a systematic review

OBJECTIVES

There is a lack of a standardised protocol for the investigation and non-operative management of paediatric multicystic dysplastic kidney (MCDK). Institutional protocols for non-operative management remain essentially ad hoc. The primary outcome of this systematic review is to establish the incidence of hypertension associated with an MCDK. The secondary outcome is to determine the malignancy risk associated with an MCDK. The tertiary outcome is to assess the rate of MCDK involution. Subsequent to these, an evidence-based algorithm for follow-up is described.

METHODOLOGY

A systematic review of all relevant studies published between 1968 and April 2017 was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were identified by specific inclusion and exclusion criteria, all of which included data relevant to the primary, secondary and tertiary outcomes. Hypertension was defined as systolic blood pressure greater than the 95th centile for gender, age and height centile. Subset analysis was performed for hypertension associated with an MCDK.

RESULTS

The primary outcome measure revealed a 3.2% (27/838) risk of developing hypertension associated with an MCDK. The secondary outcome measure noted a 0.07% malignancy risk (2/2820). The tertiary outcome measure established that 53.3% (1502/2820) had evidence of involution of the dysplastic kidney. A total of 44 cohort studies (2820 patients) were analysed.

CONCLUSION

Given the low risk of hypertension and malignancy, which is similar to the general population, the current conservative non-operative pathway is an appropriate management strategy. An algorithm to help support clinicians with ongoing management is proposed.

Follow-up of unilateral multicystic kidney dysplasia after prenatal diagnosis

OBJECTIVES

Since the introduction of antenatal diagnostic screening, multicystic kidney dysplasia (MCKD) has been diagnosed in 1 of 4300 live births. We analyze our own experience and demonstrate a management regime based on these results and existing studies.

METHODS

Retrospective data analysis was carried out in 110 patients, prenatally diagnosed with MCDK. A total of 93 patients with confirmed diagnosis of unilateral MCDK were born alive and followed up in our institutions.

RESULTS

A total of 110 unilateral cystic kidneys were prenatally diagnosed; 93 were confirmed postnatally. These children were retrospectively allocated to two treatment groups: 51 were operated upon; 42 were treated conservatively. A micturition cystourethrogram was performed 88 times, yielding 20 pathological findings. Vesicoureteral reflux was identified 11 times (12.5%). Eleven children (12%) had associated non-urological abnormalities. Cardiac and musculoskeletal malformations predominated. After 1995, nephrectomy was performed only when clinically indicated. Thirty-seven children were treated conservatively for between 4 months and 6 years (mean 33 months); 28 dysplastic kidneys exhibited size reduction. Complete involution was noted in 16 of 28 children between 7 and 29 months (mean 16.2 months).

CONCLUSION

This study provides evidence that neonatal nephrectomy of unilateral MCDK is rarely required. It also shows that the discussed malformation is not an isolated developmental abnormality. In a high proportion, associated urogenital abnormalities were present and therapeutically relevant, and determined the overall prognosis.

Non-surgical management of multicystic dysplastic kidney

OBJECTIVES

To better define the outcome and association of multicystic dysplastic kidney (MCDK) with hypertension, vesico-ureteric reflux (VUR), infection and cancer, as there is no consensus on the management of patients born with MCDK. The risk of cancer has dictated the surgical management of the disease in the past.

METHODS

The Medline database was searched for articles published between 1965 and 2006 and written in the English language, and containing the keywords 'multicystic dysplastic kidney'.

RESULTS

The inclusion criteria were met by 105 reports that were subsequently analysed. Of MCDK, 60% regress or involute within 3 years. About 25% of patients will have VUR into the contralateral kidney, of which 90% is grade <or=3. The risk of urinary tract infection appears to be associated with VUR or coexistent abnormalities rather than the MCDK. The risk of hypertension is no greater than that in the general population and nephrectomy is usually not curative. The overall risk of Wilms' tumour developing in a MCDK is <1 in 2000. All reported Wilms' tumours were identified before 4 years of age and 70% presented as a palpable mass.

CONCLUSIONS

Published reports support the non-surgical management of MCDK. Common practice has been to remove palpable or growing MCDKs, although these represent a very small fraction of MCDKs. In theory, ultrasonographic surveillance until 4 years old might allow the earlier detection of a Wilms' tumour, and decrease the intensity of chemotherapy and improve prognosis. Previous reports do not prove or disprove this concept, and the appropriate frequency of surveillance is not evident.

Outcome and cost analysis of laparoscopic or open surgery versus conservative management for multicystic dysplastic kidney

PURPOSE

To determine whether laparoscopic nephrectomy (LN), open nephrectomy (ON), or observation (OB) is most efficient for managing multicystic dysplastic kidney (MCDK).

METHODS

We performed a retrospective review of the management of our 12-year clinical experience of 32 MCDK patients to analyze the estimated total cost (ETC) of various treatment options and compare them with respect to survival, development of hypertension, and postoperative cosmetic appearance, to determine the most efficient treatment option.

RESULTS

There were 12 cases in the LN group, 6 in the ON group, and 14 in the OB group. ETC was lower for ON than for LN. But the length of preoperative observation and length of follow-up after spontaneous regression greatly affected ETC. If MCDK cases were observed > 5 years with standard investigations performed regularly, ETC was higher for the OB group than for the LN group. In 6/14 (42.9%) of OB cases, MCDK resolved within 5 years, and this subgroup had the lowest ETC up to the time of this review. Six cases initially in the OB group were managed surgically (4 by LN and 2 by ON) in accordance with parental requests, and ETC in these cases was highest. All cases are well after a mean follow-up of 5.7 years, without any impairment of renal function, or hypertension.

CONCLUSION

The decision to operate after lengthy observation increases costs. Overall, the most efficient surgical technique for managing MCDK was LN because of greater patient satisfaction with postoperative cosmesis. We recommend MCDK be treated by LN after a short period of observation.

Risk of Wilms' tumour with multicystic kidney disease: a systematic review

BACKGROUND

Children with multicystic kidney disease (MCKD) are increasingly managed conservatively and are followed up throughout childhood because they are perceived to be at increased risk of developing Wilms' tumour. With this risk still poorly defined and somewhat controversial, the strategy and the duration of follow up do not seem to be based on evidence.

METHODS

Systematic review of the literature for all published cohort studies (prospective and retrospective) of children diagnosed to have unilateral MCKD and managed conservatively.

EXCLUSION CRITERIA

bilateral MCKD, nephrectomy (not for malignancy) during the follow up period. We estimated for children with MCKD the probability of developing Wilms' tumour during the follow up period, with 95% CI using the Poisson distribution.

RESULTS

From 26 reviewed studies, no cases of Wilms' tumour developed in 1041 eligible children. The mean probability of a child with unilateral MCKD to develop Wilms' was therefore nil, with a 97.5% upper CI estimated at 0.0035 (or 3.5 per 1000 children).

CONCLUSION

The development of a national or a European registry for children with MCKD would increase the precision of their risk estimate to develop Wilms' tumour. In the meantime, there is no evidence to support any of the different modalities for following up these children by ultrasound, if indeed such a strategy is necessary.

Renal cystic neoplasms and renal neoplasms associated with cystic renal diseases: pathogenetic and molecular links

Cystic renal neoplasms represent an isolated cystic mass not accompanied by cystic change of the renal parenchyma. Although cystic change may be seen in any type of renal neoplasm, a few (i.e., cystic renal cell carcinoma, cystic nephroma, cystic partially differentiated nephroblastoma, mixed epithelial and stromal tumor) are characterized by constant cystic change that may involve the entire tumor. Cystic kidney disease is characterized by cystic change, which usually involves the kidneys in a bilateral and diffuse pattern, does not create a discreet mass, and is due to hereditary or developmental conditions. Some of the cystic kidney diseases are not known to give rise to renal neoplasm; others such as autosomal polycystic kidney disease or multicystic dysplastic kidney may fortuitously coexist with renal neoplasms. Three conditions (acquired cystic kidney disease, tuberous sclerosis, and von Hippel-Lindau disease) are associated with renal neoplasms with such a high frequency that they are considered preneoplastic. This article reviews the differential diagnoses among cystic neoplasms. It also focuses on the underlying genetic and molecular mechanisms for the relationship between cystic renal diseases and renal neoplasms.

Renal growth characteristics in children born with multicystic dysplastic kidneys

OBJECTIVES

To report on the growth characteristics of the affected and contralateral kidneys in children born with multicystic dysplastic kidneys (MCDKs).

METHODS

Thirty-three patients were enrolled from 1970 to 1995: 23 were initially managed nonoperatively (mean follow-up 3.39 years), and 10 underwent nephrectomy. Patients underwent radionuclide renal imaging and contrast voiding cystography. Serial ultrasonography was used to obtain measurements of the affected and contralateral kidneys. Blood pressure measurements and serum creatinine levels were available in some patients.

RESULTS

Among the 23 nonoperative patients, the affected MCDK involuted in 4 patients during a mean follow-up of 4.5 years at a rate of 1.02 cm/yr (24% annually); 7 kidneys decreased in size at a mean rate of 0.38 cm/yr (5.8% annually); 6 grew at a mean rate of 1.16 cm/yr (9.9% annually); 1 kidney did not change in size; and 5 children were lost to follow-up. The mean size of the contralateral kidneys at birth was 5.3 cm, 2 standard deviations larger than normal. Over time, this relative hypertrophy was maintained at a growth rate of 0.89 cm/yr (18.5% annually). Two patients who had undergone nephrectomy also had serial postoperative ultrasonic renal measurements, and contralateral growth was 0.61 cm/yr (12.16% annually). All but 1 patient had normal blood pressure measurements and serum creatinine levels.

CONCLUSIONS

Most MCDKs involute or decrease in size over time, although this may take many years. Contralateral hypertrophy is seen at birth and is maintained during childhood growth, regardless of whether the affected kidney is removed. There is no associated hypertension or malignancy when the dysplastic kidney is left in place.

Outcome and cost analysis of operative versus nonoperative management of neonatal multicystic dysplastic kidneys

PURPOSE

We determine whether nephrectomy or observation is the more appropriate treatment of neonates with multicystic dysplastic kidney in terms of medical care and cost-effectiveness.

MATERIALS AND METHODS

We retrospectively reviewed our 10-year clinical experience with 17 female and 32 male neonates presenting with multicystic dysplastic kidney who were followed with serial renal ultrasound. The literature also was reviewed.

RESULTS

Nephrectomy was performed in 12 patients (24%) for various reasons, of which family request at concomitant surgery was the most common (7). No kidney was removed due to hypertension or tumor. In the remaining 37 patients followup continues (mean 42 months) with involution developing in 9 multicystic dysplastic kidneys (24%) and 9 patients (24%) lost to followup. The total cost of 1-hour outpatient simple nephrectomy was estimated at $5,000 to $7,000 and, when performed as a concomitant procedure, it cost $2,000 to $5,000, the equivalent charges incurred for 17 to 28 serial ultrasound studies performed by a radiologist. Our review of the literature revealed that children with multicystic dysplastic kidney are at minimal risk for hypertension, pain and infection. The most important reason to perform screening renal ultrasound in this condition is to detect earlier stage Wilms tumor (3 to 10-fold the general pediatric population risk of 1/10,000 cases). With a maximum risk of 0.1% for Wilms tumor controversy exists as to whether any screening program is necessary. When screening is instituted, options include monthly parental abdominal palpation versus serial renal ultrasound. Because Wilms tumor has a rapid growth rate, when screening renal ultrasound is instituted, it must be performed no less than every 3 months until age 8 years (total of 32 studies) to screen effectively for early stage tumors.

CONCLUSIONS

The risks associated with multicystic dysplastic kidney are slight. Early nephrectomy is more cost-effective than observation in neonates with multicystic dysplastic kidney only when observation involves screening with ultrasonography every 3 months until age 8 years. Extensive parental counseling should be provided on the slight but definite risks of this condition.

Renal neoplasms of childhood

Wilms' tumor is the most common childhood renal tumor. This article describes the epidemiology, histopathologic features, and clinical manifestations of Wilms' tumor along with the spectrum of imaging findings using different modalities. The distinguishing features of other renal tumors encountered in children, such as clear cell sarcoma, rhabdoid tumor, congenital mesoblastic nephroma, multilocular cystic renal tumor, renal cell carcinoma, and angiomyolipoma are also reviewed.

Antenatal hydronephrosis. Fetal and neonatal management

As many as 1% of newborn infants have a prenatal diagnosis of hydronephrosis or significant renal pelvic dilation. Hydronephrosis often is caused by nonobstructive conditions. The likelihood of significant urologic pathology is directly related to the size of the fetal renal pelvis, and 90% with an anteroposterior diameter more than 2 cm need surgery or long-term urologic medical care. Following delivery, antibiotic prophylaxis should be administered and a renal sonogram and voiding cystourethrogram should be obtained. If there is grade 3 or 4 hydronephrosis, usually a diuretic renogram is recommended also. Pediatric urologic or pediatric nephrologic consultation usually is helpful in planing evaluation and treatment. Prenatal recognition of hydronephrosis allows neonatal diagnosis and treatment of urologic pathology, preventing complications of pyelonephritis and obstruction.

PET FDG studies of Wilms tumors

PURPOSE

Wilms tumor is the most common renal neoplasm in children. The diagnosis is usually suggested by anatomic imaging and established by biopsy or resection. The principal roles of functional imaging have been the search for skeletal metastases and evaluation of renal function. We hypothesized that, like many tumors, Wilms tumors could concentrate 18F-FDG and that evaluation of the metabolic activity of these neoplasms might prove clinically useful.

MATERIALS AND METHODS

Three patients with known or suspected Wilms tumors underwent positron emission tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) scanning (four scans). A patient with a single Wilms tumor was studied once at the time of diagnosis. The two patients with bilateral Wilms tumors were studied during therapy.

RESULTS

Uptake of FDG was present in the Wilms tumor studied at diagnosis, and in one of the tumors in each of the patients with bilateral disease studied during therapy. In all three cases, the results of the PET scans influenced therapeutic decisions.

CONCLUSION

PET FDG scanning may be useful for the management of selected patients with Wilms tumors.

Outpatient nephrectomy for nonfunctioning kidneys

We describe a surgical approach that allows multicystic dysplastic and nonfunctioning hydronephrotic kidneys to be removed on an outpatient basis through a 2.5 to 3 cm. subcostal incision. In the last 5 years 40 children (age 4 months to 5 years, mean 8.2 months) were scheduled for outpatient nephrectomy in an ambulatory surgical unit in a hospital setting. Of the 40 patients 30 had a multicystic kidney. Renal size ranged from 3 x 2 to 9.5 x 7.2 cm. Operative time ranged from 20 to 70 minutes (mean 45.4). In 34 cases (85%) an intercostal block was also performed to provide analgesia for 18 to 24 hours. Nephrectomy was done on an outpatient basis in 39 of the 40 children (98%). Mean pain score (range 0 to 5) in the last 19 patients who underwent an intercostal block was 0.68 at discharge from the hospital, 0.85 at bedtime and 0.95, 24 hours later. We conclude that nephrectomy may be performed through a small incision on an outpatient basis with minimal morbidity, and that this approach offers an alternative to laparoscopic nephrectomy and nonsurgical management of these kidneys.