Incidence Of Wilms Tumor Research Articles

A review of the genetic background in complicated WT1-related disorders.

The Wilms tumor 1 (WT1) gene was first identified in 1990 as a strong candidate for conferring a predisposition to Wilms tumor. The WT1 protein has four zinc finger structures (DNA binding domain) at the C-terminus, which bind to transcriptional regulatory sequences on DNA, and acts as a transcription factor. WT1 is expressed during kidney development and regulates differentiation, and is also expressed in glomerular epithelial cells after birth to maintain the structure of podocytes. WT1-related disorders are a group of conditions associated with an aberrant or absent copy of the WT1 gene. This group of conditions encompasses a wide phenotypic spectrum that includes Denys-Drash syndrome (DDS), Frasier syndrome (FS), Wilms-aniridia-genitourinary-mental retardation syndrome, and isolated manifestations of nephropathy or Wilms tumor. The genotype-phenotype correlation is becoming clearer: patients with missense variants in DNA binding sites including C2H2 sites manifest DDS and develop early-onset and rapidly developing end-stage kidney disease. A deeper understanding of the genotype-phenotype correlation has also been obtained in DDS, but no such correlation has been observed in FS. The incidence of Wilms tumor is higher in patients with DDS and exon-truncating variants than in those with non-truncating variants. Here, we briefly describe the genetic background of this highly complicated WT1-related disorders.

Race, ethnicity, and socioeconomic differences in incidence of pediatric embryonal tumors in the United States.

The etiology of childhood cancers and its social patterning remains largely unknown. Accounting for socioeconomic status (SES) when exploring the association between race/ethnicity and cancer incidence is necessary to better understand such etiology. We aimed to investigate differences in the incidence of embryonal tumors (ETs) by SES and race/ethnicity in the United States using population-based registries of the Surveillance, Epidemiology, and End Results (SEER) Program. Children with ETs aged 0-19 years diagnosed between 2000 and 2015 were ascertained from the census tract-level SEER database. SES was measured using a tract-level composite index. Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) by SES quintile and race/ethnicity were estimated using multivariable Poisson regression models. The majority of tumors had lower incidence among nonwhite children compared with non-Hispanic (NH) white children, after controlling for SES. NH blacks had a higher incidence of Wilms tumor than NH whites (IRR: 1.26; 95% CI, 1.13-1.39). There was an increasing linear trend (P=0.0001) across increasing SES quintile for embryonal rhabdomyosarcoma after controlling for race/ethnicity. Effect modification by race/ethnicity of the relationship between SES and tumor incidence was observed for several groups. Hispanics had a significant, linear trend (P=0.0005) in the incidence of Wilms tumor, while Asian/Pacific Islanders experienced a significant inverse trend (P=0.0002). Results from this study suggest differences in the incidence of several ETs by race/ethnicity and that these differences may be modified by SES. Investigation of potential risk factors that are socially patterned is warranted.

Global Disparities in Wilms Tumor

BackgroundWilms tumor accounts for more than 90% of all malignant kidney neoplasms in children. Survival after diagnosis and treatment is excellent in most high-income countries. Low- and middle-income countries (LMICs) continue to struggle with Wilms tumor detection and treatment. The purpose of this study was to compare the global incidence and outcomes of Wilms tumor. Material and methodsWilms tumor incidence data from the World Health Organization (WHO), International Incidence of Childhood Cancer, Volume III, was analyzed according to world region and country socioeconomic status using descriptive statistics and independent-sample Kruskal–Wallis Test. A literature review was also performed to assess outcomes and identify common themes. ResultsWilms tumor was most common in children aged 0-4 y (median incidence 15.1 [IQR 11.8-18.7] ASR/million). High-income countries reported significantly higher median incidence than middle-income countries (8.6 [7.4–9.3] versus 6.1 [4.9–8.7] ASR/million; P < 0.01), although low-income countries reported the highest median incidence overall (9.8 [6.2–16.4] ASR/million). Low-income countries had the fewest countries with registries (n = 6). Overall survival ranged from 70% to 97% in high-income countries, 61%–94% in upper-middle-income countries, 0%–85% in lower-middle-income countries, and 25%–53% in low-income countries. Delay in diagnosis, lack of available treatment, and inadequate follow up contributed to the large variations in outcomes. ConclusionsReported Wilms tumor incidence is highest in low-income countries, and these are also the countries that have the lowest survival. Lack of significance may reflect incomplete and absent data reporting from lower income countries. Accurate and comprehensive registries are the first steps to appropriate resource allocation in order to improve outcomes for this highly curable childhood malignancy.

Cancer Risk in Klippel-Trenaunay Syndrome.

Background: Klippel-Trenaunay syndrome (KTS) is an overgrowth syndrome defined by capillary/venous/lymphatic malformations (CVLM) with soft tissue and/or bone hypertrophy. Whether KTS predisposes to cancer is not clear. Methods and Results: We surveyed members of the K-T Support Group (KTSG) and reviewed PubMed for "Klippel Trenaunay Syndrome" or "CVLM" and "cancer." Individuals with cancer were reviewed for confirmation of KTS, tumor type, location, and age at presentation. Of 223 KTSG respondents, 24 (10.8%) reported 26 malignancies or benign brain tumors (diagnosed from 6 months to 68 years of age, median 41 years), including 3 who were younger than 18 years (2 with Wilms tumor). Nine of twenty-six cancers were basal cell carcinomas (4% of respondents). From 475 articles, we identified 11 cancers or brain tumors in 10 individuals with KTS. Four of these were in children (Wilms tumor n = 2; rhabdomyosarcoma n = 1; serous borderline tumor n = 1). Tumors in adults included basal cell carcinoma (n = 1), squamous cell carcinoma of skin (n = 2), and angiosarcoma, Hodgkin disease, glioblastoma, malignant hemangiopericytoma in one patient each. Ulceration or lymphedema associated with VLM or capillary malformations were associated with some basal cell or squamous cell carcinomas and angiosarcomas. Conclusions: The risk of embryonal cancer other than Wilms tumor in children with KTS does not appear to be higher than in the general population. Wilms tumor incidence is under 5%, and routine surveillance is not indicated. In adults, particular attention should be paid to skin in the area of malformations. These conclusions may not apply to all overgrowth syndromes with vascular malformations.

Trends in Urologic Indications for Pediatric Renal Transplantation Over a 27-Year-period United Network for Organ Sharing (UNOS) Database

To elucidate the trends in urologic causes for renal transplant in the pediatric population using a national database. Little is known about the specific pediatric urologic conditions and resultant trends that precede renal transplantation. We reviewed the United Network for Organ Sharing (UNOS) database for pediatric patients (<18 years old) who underwent renal transplantation from January 1988 to September 2015. We included those patients who received a renal transplant because of a urologic condition. Over 27 years, 7291 of 20,213 children (36%) underwent renal transplant secondary to a urologic condition. The 2 most common indications were hypoplasia/dysplasia/dysgenesis/agenesis (HDDA, 35.1%) and congenital obstructive uropathy (COU, 25.7%). The incidence of COU has increased from 18% to 30%, and the incidence of Wilms tumor has remained relatively consistent at 1.8% per year. In addition, 68% of all urologic renal transplants were performed in men compared with women. However, a higher percentage of women required transplantation because of Wilms tumor (3.1% vs 1.2%) and chronic pyelonephritis (17.6% vs 7.9%). Overall, the majority of patients (61.5%) who underwent renal transplantation were white, 18.8% Hispanic, and 15.3% black. HDDA and COU consistently have been the most common urologic indications for renal transplantation. Both are the leading causes in men, whereas HDDA and chronic pyelonephritis are predominant in women. Higher rate of renal transplant during the ages of 11-17 years is suggestive of increased burden on poorly functioning kidneys during times of adolescent growth.

Clinicopathological Profile of Wilms’ Tumour in Children

Introduction: Wilms’ tumor is the most common primary malignant renal tumor of childhood. It is important to pick up the children with wilms’ tumor earlier as early stages has excellent outcomes after treatment. Objective : To find out the common clinical presentations and pathological profile of Wilms’ tumor in children. Methods and Materials : A hospital based prospective study done with twenty diagnosed patients of Wilms tumour enrolled from department of Pediatric haemato-oncology, BSMMU, Dhaka in the period between January to December 2008. Results- The peak incidence of Wilms’ tumor was in 1 to 5 years age group (80%,n=16). Median age at presentation was 49 months with male: female ratio 1.8:1.The most common presentation was abdominal swelling (80%,n=16),followed by flank mass (75%,n=15), abdominal pain (55%,n=11), haematuria (15%,n=3), hypertension (10%,n=2). Thirteen raised from right kidney, ratio of right to left involvement 1.8:1. Histologically 13(65%) patients had triphasic histology having blastemal, stromal and epithelial elements, 7(35%) was biphasic having blastema and epithelia. All had favourable histological pattern. Most patients presented in stage III (55%,n=11) followed by stage II (25%,n=5), Stage IV(10%,n=2), Stage I(10%,n=2). No bilateral presentation. Conclusions : Most of the patients of Wilms’ tumor presented within 1 to 5 years of age(80%) with abdominal distension(80%) and flank mass(75%), few associated with haematuria(15%) and hypertension(10%). Histologically all were favourable and maximum presented in stage III (55%) followed by stage II(25%). DOI: http://dx.doi.org/10.3329/jbcps.v32i1.21015 J Bangladesh Coll Phys Surg 2014; 32: 5-8

Perinatal risk factors for Wilms tumor in a Swedish national cohort

Perinatal risk factors including high birth weight have been associated with Wilms tumor in case-control studies. However, these findings have seldom been examined in large cohort studies, and the specific contributions of gestational age at birth and fetal growth remain unknown. We conducted the largest population-based cohort study to date consisting of 3,571,574 persons born in Sweden in 1973-2008, followed up for Wilms tumor incidence through 2009 to examine perinatal risk factors. There were 443 Wilms tumor cases identified in 66.3 million person-years of follow-up. After adjusting for gestational age and other perinatal factors, high fetal growth was associated with increased risk of Wilms tumor among girls (hazard ratio per 1 standard deviation (SD), 1.36; 95% CI 1.20-1.54; P < 0.001), but not boys (1.10; 95% CI 0.97-1.25; P = 0.14) (P interaction = 0.02). Among girls, high fetal growth was associated with disease onset before age 5 years (odds ratio per 1 SD, 1.47; 95% CI 1.28-1.69; P < 0.001), but not beyond (1.00; 95% CI 0.76-1.31; P = 0.99). No clear associations were found for gestational age at birth or other perinatal factors. In this large cohort study, high fetal growth was associated with Wilms tumor before age 5 years among girls. These findings suggest that early-life growth factor pathways for Wilms tumor may be more common among girls than boys. Further elucidation of these mechanisms may reveal better targets for prevention or treatment of specific subtypes of Wilms tumor.

Different incidences of epigenetic but not genetic abnormalities between Wilms tumors in Japanese and Caucasian children

Epidemiological studies show that the incidence of Wilms tumor (WT) in East-Asian children is half of that in Caucasian children. Abnormalities of WT1, CTNNB1, WTX, and IGF2 were reported to be involved in Wilms tumorigenesis in Caucasians, although none of the studies simultaneously evaluated the four genes. WTX forms the β-catenin degradation complex; however, the relationship between WTX abnormality and CTNNB1 mutation was uncertain in WTs. We examined abnormalities of the four genes in 114 Japanese with WTs to clarify the relationship between genetic and epigenetic factors and the incidence of WTs. We found that abnormalities of WTX and CTNNB1 were mutually exclusive, and that although CTNNB1 mutation was frequent in WTs with WT1 abnormality, but rare in WTs without, the incidences of WTX abnormality were similar between WTs with or without WT1 abnormality. These findings were consistent with those reported in Caucasian populations, and indicate multiple roles of WTX abnormality. Abnormalities of WT1, WTX and CTNNB1, and loss of IGF2 imprinting (LOI) were detected in 31.6%, 22.8%, 26.3%, and 21.1% of the 114 WTs, respectively. When we selected 101 sporadic WTs, the incidences of WT1, CTNNB1, or WTX abnormality were generally comparable between the two populations, whereas the incidence of IGF2 LOI was lower in Japanese than that of IGF2 LOI reported in Caucasians (P = 0.04). This is the first comprehensive study of the four genes, and the results supported the hypothesis that the lower incidence of IGF2 LOI contributes to the lower incidence of WTs in Japanese children.

Abstract 629: Childhood cancer incidence trends in association with folic acid fortification in the United States (1986-2008)

Abstract Folic acid plays a critical role in embryonic development and sufficient maternal prenatal folic acid consumption significantly reduces the incidence of congenital abnormalities in offspring. Epidemiological evidence supports the hypothesis that maternal prenatal folic acid supplementation lowers the risk of childhood cancer in offspring; however a systematic evaluation of population-based childhood cancer incidence trends following fortification of enriched grain products with folic acid in the U.S. in 1996-1998 has not been previously reported. Here we describe temporal trends in childhood cancer incidence in association with U.S. folic acid fortification. Using Surveillance, Epidemiology, and End Results program data (1986-2008) we calculated incidence rate ratios (IRRs) and 95% confidence intervals (CIs) to compare pre- and post-fortification incidence rates in children aged 0-4 years. Using joinpoint and loess regression models, we looked for inflection points during this period where the incidence trend changed in magnitude and/or direction. From 1986-2008, 8,829 children aged 0-4 years were diagnosed with malignancies, including 3,790 and 3,299 in utero during the pre- and post-fortification periods, respectively. Pre- and post-fortification incidence rates were similar for all cancers combined (IRR=1.01, 95% CI: 0.96-1.06) and for most specific cancer types examined. Rates of ependymomas (IRR=0.70, 95% CI: 0.51-0.97), primitive neuroectodermal tumors (PNETs) (IRR=0.56, 95% CI: 0.37-0.84) and Wilms tumor (WT) (IRR=0.80, 95% CI: 0.68-0.95) were significantly lower post-fortification. Notably, a greater reduction in post-fortification incidence was observed for the latter two subtypes upon restricting the analysis to infants, in whom any true effect of folic acid is expected to be greater. Joinpoint regression models detected increasing PNET incidence from 1986-1993 (annual percent change, APC=11.5, 95% CI: -5.0-31.0) followed by a sharp decrease from 1993-2008 (APC=−7.4%, 95% CI: -12.1- -2.4), and increasing WT incidence from 1986-1997 (APC=2.2, 95% CI: -1.2-5.8) followed by a sizable decline from 1997-2008 (APC=−4.0%, 95% CI: -7.3- -0.6). Loess curves indicated similar patterns. These results provide support for decreases in PNET and WT incidence, but not other childhood cancers, following U.S. folic acid fortification. Ten years of data are now available post-fortification and any substantial changes in childhood cancer rates attributable to fortification should be evident. Drawing firm conclusions regarding the isolated effects of folic acid is difficult, however, as other temporal trends occurred during the time period examined. Alternative study designs are required to rule out other explanations and confirm causal relationships. Supported by NIH Grants T32 CA099936 and K05 CA157439, and Children's Cancer Research Fund, Minneapolis, MN. A.M. Linabery and K.J. Johnson contributed equally to this work. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 629. doi:1538-7445.AM2012-629

Wilms tumor incidence in children with 2q terminal deletions: A cohort study

Three individuals with chromosome 2q terminal deletions have been reported in the medical literature to have developed Wilms tumor. By looking at a UK national cohort, we aimed to ascertain the chance of an individual with a 2q terminal deletion developing a Wilms tumor. The objective was to clarify screening recommendations. All individuals over a 40-year period with chromosome 2q terminal deletions were ascertained from the Chromosome Abnormality Database. The names and dates of birth of these individuals were obtained from the Regional Cytogenetic Departments where the original chromosome analyses were performed. These data were collated and compared with the National Registry of Childhood Tumors. One hundred twenty-nine subjects were identified over a 40-year study period. Only a single individual in our national cohort was affected by Wilms tumor. This individual had an add(2)(q35) karyotype. We conclude that the incidence of Wilms tumor in the majority of individuals with a 2q terminal deletion is low, and is below the recommended threshold for surveillance for tumor development.

Race Disparities in Wilms Tumor Incidence and Biology

Wilms tumor (WT) is thought to arise in children of Black African ancestry with greater frequency than in Whites. To clarify the biological basis for race disparities in WT, we first verified that Black children residing in Tennessee have an increased incidence of WT, and second, established molecular profiles in WT that are specific to race. To assess race disparities in WT epidemiology, the Tennessee Cancer Registry (TCR) was queried for all in-state patients less than 20 y of age and registered between 1999 and 2008. To explore race disparities in WT biology, six Black and four White WT specimens acquired in Tennessee were analyzed using imaging mass spectrometry (IMS). TCR data show that Black children are over-represented among WT patients (29%) relative to all other childhood cancers (18.5%; P = 0.01). WT ranked the fifth most common cancer diagnosis among Blacks, but ninth among Whites. The diagnosis of WT occurred 79% more frequently among Blacks (n = 28) than Whites (n = 69; P = 0.01), and proportionally more Blacks tended to present with distant disease. Although overall survival from WT was not statistically different between Blacks (92.9%) and Whites (94.0%), Black males showed the lowest survival (85%; P = 0.21). IMS analysis identified peptide spectra from both WT blastema and stroma that independently classify specimens according to race with greater than 80% accuracy. In Tennessee, Black children appear more susceptible than Whites to develop WT. Race-specific molecular profiles can be determined that may help to clarify pathways of Wilms tumorigenesis and the biological basis for race disparities in WT incidence and biology.

Abstract 3426: The lower incidence of loss of IGF2 imprinting, but not that of WT1, WTX or CTNNB1 abnormality may cause different incidence rates of Wilms tumor between Japanese and Caucasian populations

Abstract Incidence rates of Wilms tumor (WT) markedly differ among ethnic groups; the epidemiological studies showed that the incidence of WT in Japanese children is about half of that of WT in Caucasian children. In Hawaii and Britain, the rates of WT in Asian descent were less than two-third or a half of those in Caucasian children, and these findings suggest that the different incidences of WT may be caused by genetic factor(s), but not by environmental factor(s). Development of WT is associated with mutations of certain genes, including WT1, WTX and CTNNB1, and abnormal expression of IGF2, namely, loss of imprinting (LOI). The frequency of these abnormalities occurs in 10-15% (WT1), 7-15% (WTX), 5-13% (CTNNB1) and 30-60% (IGF2 LOI) of sporadic WTs based on the studies in North-American or European children. To demonstrate the molecular characteristic in Japanese WT, we examined mutations/deletions of WT1, WTX and CTNNB1 using Southern blot, SNP array, sequencing and/or real-time PCR, and expression pattern of IGF2 using the ApaI polymorphism site in exon 9 and the methylation status of the CTCF binding site 6 at H19-differential methylated region (DMR) in 101 sporadic and 13 syndromic WTs in Japanese children. Abnormalities of WT1, WTX or CTNNB1 were detected in 24 (23.8%), 24 (23.8%), and 21 (20.8%)of 101 sporadic WTs, respectively, and in 13 (100%), 0, and 10 (76.9%) of 13 syndromic WTs, respectively. LOI of IGF2 was found in 24 (23.8%) of sporadic WTs and in 1 (7.7%) of syndromic WTs. Thus, the incidence of WT1, WTX or CTNNB1 abnormality was higher, but that of LOI of IGF2 was lower in Japanese children than in Caucasian counterparts. Because the incidence of WT in Japanese children is about half of that of WT in Caucasian ones, the population-based incidences of WT1, WTX or CTNNB1 abnormality may be similar between the two ethnic groups. In contrast, the incidence rate of IGF2-LOI in Japanese children was lower than those of IGF2-LOI in Caucasian children, and the difference in the population-based incidences is much larger. A recent study of 47 Japanese patients with Beckwith-Wiedemann syndrome revealed a significantly lower frequency of H19-DMR hypermethylation in Japanese patients than in North American and European patients (Sasaki et al, Eur J Hum Genet 2007). This and the present findings suggest that susceptibility to epigenetic alterations differs between Japanese and Caucasian populations. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3426.

Incidences of Kidney, Pelvis, Ureter, and Bladder Cancer in a Nationwide, Population-based Cancer Registry, Denmark, 1944-2003

To determine changes in the population-based incidence rates, degree of histologic verification, and morphologic distribution of tumors of the kidney, pelvis, and ureter and bladder in both sexes for the duration of 60 years in Denmark. Age-standardized incidence rates in 5-year age and calendar intervals, histologic verification and morphologic distribution were derived from reports to the Danish Cancer Registry. The incidence of kidney tumors increased by 78% among men and 32% among women during the study period; the incidence of pelvis and ureter tumors increased by 1070% and 2785%, respectively, and those of bladder tumors increased by 325% and 195%, respectively. The incidence of Wilms tumor was stable; the incidence of other kidney tumors leveled out during the last 30 years of the period and those of other 2 groups during the last 20 years. The frequency of histologic verification was stable for pelvis and ureter cancers and Wilms tumor and increased for kidney and bladder tumors. Most of the kidney tumors were of epithelial origin and most others were of urothelial origin. The overall incidences of all tumors increased in both sexes during the 60-year period. Some of the increase could be due to improved diagnosis. The recent decline in rates might be due to reduced exposure to risk factors.

Molecular Pathology and Epidemiology of Nephrogenic Rests and Wilms Tumors

Perilobar (PLNR) and intralobar nephrogenic rests (ILNR) are distinct precursor lesions of Wilms tumors that have different structural, clinical, genetic, and epidemiologic features. Wilms tumors in East-Asian children have unique epidemiologic features in that the incidence is about half that of white children, an early age at diagnosis, a male predominance, and an association with ILNR. Loss of IGF2 imprinting is associated with PLNR more commonly seen in Wilms tumors from white children than tumors from children of Asian descent. Therefore, this epigenetic difference and the higher frequency of PLNR provide an explanation for the interethnic variations in the incidence of Wilms tumor. The histopathologic, clinical, and genetic differences between ILNR and PLNR are described in this review, followed by a description of an epigenetic mechanism that underlies PLNR formation and the unique epidemiologic feature of Wilms tumors.

Congenital diaphragmatic hernia in WAGR syndrome

Wilms tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is a contiguous gene deletion syndrome involving the Wilms tumor 1 gene (WT1), the paired box gene 6 (PAX6), and possibly other genes on chromosome 11p13. WT1 is required for normal formation of the genitourinary system and the high incidence of Wilms tumor and genitourinary anomalies found in patients with WAGR are attributed to haploinsufficiency of this gene. It has been hypothesized that WT1 also plays an important role in the development of the diaphragm. During mammalian embryonic development, WT1 is expressed in the pleural and abdominal mesothelium that forms part of the diaphragm. Furthermore, mice that are homozygous for a deletion in the mouse homolog of WT1 have diaphragmatic hernias. Case reports describing congenital diaphragmatic hernias in infants with Denys-Drash and Frasier syndromes, both of which can be caused by mutations in WT1, provide additional support for this hypothesis. We report an infant with aniridia, bilateral cryptorchidism, vesicoureteral reflux, and a right-sided Morgagni-type diaphragmatic hernia. G-banded chromosome analysis revealed a deletion of 11p12-p15.1. Breakpoint regions were refined by fluorescence in situ hybridization (FISH) and deletion of the WAGR critical region, including WT1, was confirmed. A review of the medical literature identified a second patient with a deletion of 11p13, a left-sided Bochdalek-type diaphragmatic hernia, and anomalies that suggest a diagnosis of WAGR including bilateral microphthalmia, a small penis, bilateral cryptorchidism, and a hypoplastic scrotum. These cases demonstrate that congenital diaphragmatic hernia can be associated with WAGR syndrome and suggest that deletions of WT1 may predispose individuals to develop congenital diaphragmatic hernia.

The occurrence of Wilms tumor in horseshoe kidneys: A report from the National Wilms Tumor Study Group (NWTSG)

Background/Purpose: An increased incidence of Wilms tumor has been noted in patients with a horseshoe kidney. These represent a difficult diagnostic and therapeutic challenge. The charts of all National Wilms Tumor Study Group (NWTSG) patients with Wilms tumor occurring in a horseshoe kidney were reviewed. Methods: From 1969 to 1998, 8,617 patients were enrolled in the NWTSG. Forty-one patients were found to have a Wilms tumor arising in a horseshoe kidney for an incidence of 0.48%. Their records were reviewed retrospectively. Results: Horseshoe kidney was not recognized preoperatively in 13 patients, 10 of whom were evaluated with computed tomography (CT). Four of the 10 also had renal ultrasonography and one an intravenous pyelogram (IVP). Two of the 13 were evaluated with an IVP only, and the last had no preoperative imaging studies performed. Stage at presentation was stage I, 10 pts; stage II, 10; stage III, 12; stage IV, 6; stage V, 3. Primary surgical resection was performed in 26 patients, including 23 nephrectomies and 3 partial nephrectomies. Fifteen children were treated with preoperative chemotherapy after initial biopsy of the tumor. The mean total remaining renal parenchyma after all operations (excluding treatment of relapses) was approximately 75%. Surgical complications occurred in 14.6% of patients, including 2 urine leaks, 2 ureteral obstructions, and 1 ureteral injury. Two patients had transient renal failure. Conclusions: The diagnosis of horseshoe kidney often was missed on preoperative imaging. Accurate preoperative diagnosis is important in planning the operative approach and may help to decrease complications related to transection of the urinary collecting system. Although 37% of patients with Wilms tumor arising in a horseshoe kidney were judged inoperable at initial exploration, all were amenable to resection after chemotherapy. J Pediatr Surg 37:1134-1137. Copyright 2002, Elsevier Science (USA). All rights reserved.

RENAL FINDINGS ON RADIOLOGICAL FOLLOWUP OF PATIENTS WITH BECKWITH-WIEDEMANN SYNDROME

Purpose The Beckwith-Wiedemann syndrome is most commonly characterized by macroglossia and abdominal wall defect(s), and it carries a predisposition to embryonal tumors, including Wilms tumor. We report our experience with the character and incidence of renal disease in patients with the Beckwith-Wiedemann syndrome, and discuss the role of radiological followup. Materials and Methods We reviewed the medical records of all patients diagnosed with the Beckwith-Wiedemann syndrome who were treated at our institution between March 1979 and February 1998. Radiological followup consisted of renal ultrasound at approximately 3 to 6-month intervals with the addition of computerized tomography or magnetic resonance imaging (MRI) in patients with an indeterminate lesion(s) or nephrogenic rest(s). Results A total of 29 patients were identified. Of these cases renal ultrasound showed normal kidneys bilaterally in 19 (70%), simple cysts in 5 (19%), indeterminate lesion(s) in 2 (7%) and nephrocalcinosis in 1 (4%). Nephrogenic rests were followed with MRI in 1 patient, and 1 in whom a 2 cm. mass was revealed by followup MRI underwent partial nephrectomy and chemotherapy for stage I Wilms tumor. Conclusions The 3.7% incidence of Wilms tumor in our patients with the Beckwith-Wiedemann syndrome is similar to that in previously published reports. Aggressive followup by a sensitive radiological technique is warranted in cases of the Beckwith-Wiedemann syndrome, and associated hemihypertrophy and/or nephromegaly with or without evidence of a Wilms tumor precursor. The detection of suspected malignant disease at an early stage may permit curative nephron sparing surgery.