Fetal and neonatal renal tumors

MR Imaging of the Fetal Genitourinary Tract

Fetal MR imaging overcomes many of the technical barriers of ultrasound and is an important diagnostic tool for fetal genitourinary (GU) anomalies. It is suited for evaluation of GU anomalies because of the fluid-sensitive sequences and superior soft tissue contrast. Often GU malformations are part of a multisystem genetic or congenital condition, and imaging the entire fetus with MR adds additional clarity about the extent of disease. It adds confidence to diagnoses of renal agenesis, urinary tract dilation, cystic disease, and tumors. It is particularly useful to delineate anatomy in complex GU malformations. This additional information guides counseling.

Diagnostic magnetic resonance imaging characteristics of congenital mesoblastic nephroma: a retrospective multi-center International Society of Pediatric Oncology-Renal Tumor Study Group (SIOP-RTSG) radiology panel study

BACKGROUND

Congenital mesoblastic nephroma is the most common solid renal tumor in neonates. Therefore, patients <3 months of age are advised to undergo upfront nephrectomy, whereas invasive procedures at diagnosis in patients ≥3 months of age are discouraged by the International Society of Pediatric Oncology-Renal Tumor Study Group (SIOP-RTSG). Nevertheless, discriminating congenital mesoblastic nephroma, especially from the more common Wilms tumor, solely based on imaging remains difficult. Recently, magnetic resonance imaging (MRI) has become the preferred modality. Studies focusing on MRI characteristics of congenital mesoblastic nephroma are limited.

OBJECTIVE

This study aims to identify diagnostic MRI characteristics of congenital mesoblastic nephroma in the largest series of patients to date.

MATERIALS AND METHODS

In this retrospective multicenter study, five SIOP-RTSG national review radiologists identified 52 diagnostic MRIs of histologically proven congenital mesoblastic nephromas. MRI was performed following SIOP-RTSG protocols, while radiologists assessed their national cases using a validated case report form.

RESULTS

Patients (24/52 classic, 11/52 cellular, and 15/52 mixed type congenital mesoblastic nephroma, 2/52 unknown) had a median age of 1 month (range 1 day-3 months). Classic type congenital mesoblastic nephroma appeared homogeneous with a lack of hemorrhage, necrosis and/or cysts, showing a concentric ring sign in 14 (58.3%) patients. Cellular and mixed type congenital mesoblastic nephroma appeared more heterogeneous and were larger (311.6 and 174.2 cm3, respectively, versus 41.0 cm3 for the classic type (P<0.001)). All cases were predominantly T2-weighted isointense and T1-weighted hypointense, and mean overall apparent diffusion coefficient values ranged from 1.05-1.10×10-3 mm2/s.

CONCLUSION

This retrospective international collaborative study showed classic type congenital mesoblastic nephroma predominantly presented as a homogeneous T2-weighted isointense mass with a typical concentric ring sign, whereas the cellular type appeared more heterogeneous. Future studies may use identified MRI characteristic of congenital mesoblastic nephroma for validation and for exploring the discriminative non-invasive value of MRI, especially from Wilms tumor.

Congenital and gynecological tumors: A review

Congenital tumors are rare, and malignant congenital tumors are uncommon. Benign tu,mors might be life-threatening, depending on the location and size of the tumor. Different factors affect congenital tumors, such as maternal and placental hormones and environmental factors such as drugs, radiation, and infection. Developing fetal imaging methods and continuous follow-up during pregnancy are important factors in congenital tumor prognosis. Ultrasound is the most common method used for fetal evaluation. The complementary evaluation method is MRI. Both methods are helpful and widely spread for the detection of congenital tumors. These imaging methods help the medical team make a suitable decision about therapy. Some of these tumors regressed spontaneously, and some need surgical treatments. Treatment of tumors has developed rapidly, and recently molecular-targeted drugs have been used.

Fetal Wilm's tumor detection preceding the development of isolated lateralized overgrowth of the limb: a case report and review of literature

Fetal Wilms tumor (WT) is extremely rare, but with advances in fetal imaging, more cases are being reported. The management of these cases remains challenging. Herein, we present the case of a full-term female infant diagnosed antenatally at 32 weeks of gestation with a right solid renal mass detected on routine prenatal ultrasound without polyhydramnios. At birth, the infant was healthy, with no evidence of dysmorphic features or abnormal laboratory tests to suggest a predisposition syndrome. Her family history was also unremarkable. A successful radical right nephrectomy was performed on day 2 of life revealing a classic WT. She received vincristine as adjuvant chemotherapy without any complications. At the age of 1 month, the infant developed isolated lateralized overgrowth of the right lower limb suspicious of Beckwith-Wiedemann syndrome. At the latest follow-up of 4 years, the child is healthy and disease-free with conserved asymmetry of lower limbs. The case provides insights into the challenging diagnosis and treatment of fetal WT. A review of the literature suggests that the presence of polyhydramnios is a worse prognostic factor while the combination of best supportive care and surgery remains the best management. Fetal WT can be associated with predisposition syndromes; however, their first manifestations can develop after the diagnosis of cancer has been made, as in our patient. We propose starting active surveillance programs and genetic testing for any case of fetal WT.

Infantile Congenital Mesoblastic Nephroma Leading to Multi-Systemic End-Organ Disease

Congenital mesoblastic nephroma (CMN) is a rare infantile abdominal tumor that is highly curable with early surgical intervention. However, chronic, unrecognized tumor burden can cause significant compression of local vascular and solid structures, resulting in multi-systemic end-organ dysfunction. In this case report, we describe the effects of chronic abdominal compartment syndrome in an infant due to a solid renal tumor and its anesthetic implications.

Prenatal Course and Sonographic Features of Congenital Mesoblastic Nephroma

Background: Congenital mesoblastic nephroma (CMN) is the most common renal tumor among fetuses and infants before the age of 6 months. It usually behaves as a benign tumor. The prenatal features and outcomes of pregnancies with fetal CMN have never been systematically reviewed and analyzed, whereas neonatal or pediatric series have been published several times. The aims of this study are to (1) describe the prenatal natural course and prenatal sonographic char-acteristics of CMN; (2) determine the outcomes of pregnancies with fetal CMN; and (3) demonstrate typical sonographic images together with video clips of prenatal CMN, as an educational example based on our index case presented here. Methods: Studies focused on fetal CMN, including those consecutively published on PubMed from 1980 to June 2022 as well as the index case presented here, were identified and validated to perform a systematic review. The data of fetal imaging and the prenatal course of pregnancies were extracted for analysis. Results: The findings derived from 41 cases of review are as follows: (1) No single case has been diagnosed in the first half of pregnancy. No cases were detected during routine anomaly screening at mid-pregnancy. All cases were de-tected in the third trimester or late second trimester. (2) Polyhydramnios is very common and is the first clinical manifestation in most cases, leading to detailed ultrasound in the second half of pregnancy. (3) Preterm birth and low birth weight are the most common adverse pregnancy out-comes, resulting in neonatal morbidity. (4) Hydrops fetalis, though relatively rare, can be associated with CMN and is a grave sign. (5) Prenatal diagnosis is essential since it is critical for the antenatal plan, comprising either referral to a tertiary care center or proper surveillance to prevent serious obstetric complications, especially preterm birth. (6) Ultrasound is the primary tool for prenatal diagnosis of CMN, whereas MRI can be used as an adjunct if some other tumors are suspicious or sonographic features are not typical for CMN. Conclusion: In contrast to CMN in neonates, fetal CMN is much more serious since it significantly impacts adverse pregnancy outcomes and perinatal morbidity and mortality. The typical prenatal course and the sonographic features of CMN are described.

Cellular congenital mesoblastic nephroma detected by prenatal MRI: a case report and literature review

Congenital mesoblastic nephroma (CMN) is a rare tumor, yet it is the most frequently diagnosed renal neoplasm in the first 3 months of life. CMN reports with prenatal magnetic resonance imaging (MRI) are scarce. Our aims were to describe a case with fetal MR imaging along with other findings, and to review the literature concerned with prenatal MRI detection of CMN. Upon routine ultrasound (US) examination of a 36-week pregnant woman, a fetal abdominal mass was disclosed. Prenatal MRI revealed a large, well-circumscribed renal mass of solid and cystic components, not invading the adjacent tissues, but compressing normal renal parenchyma of the lower pole of the left kidney. Thus, a low malignant renal tumor was considered. After Cesarean delivery, imaging including US and computerized tomography (CT) scan was performed on the apparently healthy boy and verified the prenatal MRI finding. Accordingly, left nephrectomy was performed at the age of 12 days. The pathology confirmed CT results of the solid and cystic components of the mass, in addition to the necrotic and hemorrhagic constitution. Cellular CMN was diagnosed, and ETV6 gene rearrangement was demonstrated by FISH analysis. No recurrence was detected within the 40 months follow-up after the operation. Our report described a rare and seldomly detected renal tumor in utero with the aid of MRI and reviewed the few related reports in the literature in which MRI was performed prenatally. This report also highlights the need for prenatal MRI as a complementary tool to US in cases with suspected fetal renal mass and recommends its use for carefully managing the possible risks during the perinatal period.

Prenatal diagnosis and postnatal management of congenital mesoblastic nephroma: A case report and literature review

BACKGROUND

Congenital mesoblastic nephroma (CMN) is a rare renal tumour in children, the most common kidney tumour in the neonatal period. It can be divided into three types, classical, cellular and mixed.

CASE PRESENTATION

A 31-year-old Chinese woman had no apparent foetal abnormality in regular prenatal care during the first and second trimesters. At 33 weeks of gestation, a solid mass in the right kidney was noted with echoes similar to liver and hypervascularity. It grew larger during late pregnancy. The infant was transferred to have a radical nephrectomy on the 9th day after birth. The postoperative histopathological result indicated classical CMN.

CONCLUSION

CMN could be detected prenatally, mainly during late pregnancy. The postnatal outcome is good.

Congenital Bilateral Wilms Tumor: A Case Report

Compare to congenital mesoblastic nephroma in fetus, congenital wilms tumor is extremely rare. Herein we report a case of congenital bilateral solid masses on antenatal ultrasound. The mass was evaluated by ultrasonography and contrast computed tomography scan in postnatal period, and the patient was undergoing tumor enucleation separately in short period after neoadjuvant chemotherapy. The diagnosis was confirmed by histology analysis for each side, and the treatment was taken according to the International Society of Pediatric Oncology.

Prenatal diagnosis and postnatal management of congenital mesoblastic nephroma: Experience at a single center in China

OBJECTIVE

To review the prenatal and postnatal clinical characteristics and pathological subtypes, as well as the surgical outcome for congenital mesoblastic nephroma (CMN) cases.

METHOD

A retrospective review was performed in 11 cases with CMN prenatally diagnosed at a single center between 2015 and 2019. The clinical characteristics, surgical outcome, histopathology, and follow-up were retrospectively obtained and reviewed.

RESULTS

The median gestational age at which the sonographic diagnosis was made was 35 weeks. Polyhydramnios was found in four (36.4%) cases, and all resulted in a preterm birth. Nine infants had hypertension. Ten cases underwent radical nephrectomy, and one underwent radical nephrectomy and partial adrenalectomy. The pathological results showed that six tumors were classical variants, four mixed variants, and one was a cellular variant. Three cases presented as a stage I, eight as stage II, and no stage III or IV cases were diagnosed. All patients are alive so far. At a median follow-up of 14 months, no local recurrence, or remote metastases were found.

CONCLUSION

The prognosis of prenatal CMN cases is excellent after early surgery.

Neonatal Renal Tumors

Renal tumors are rare in the neonatal period. Although some may be detected prenatally, a greater proportion present after birth, most often with a palpable abdominal mass with or without other associated symptoms. Cross-sectional imaging is typically followed by radical nephrectomy to make a specific histologic diagnosis to determine the need for additional therapy. This article reviews the clinical presentation, workup, treatment, and outcomes for neonates with some of the more common renal tumors seen in this population.

Imaging of solid congenital abdominal masses: a review of the literature and practical approach to image interpretation

Fetal abdominal tumors are rare, usually benign, and cause a great deal of anxiety for expectant parents and the physicians counseling them. In this paper the author reviews the most common fetal abdominal tumors in the liver (hemangioma, mesenchymal hamartoma, hepatoblastoma, metastases) and the kidney (congenital mesoblastic nephroma, Wilms tumor, malignant rhabdoid tumor, and clear cell sarcoma), and suprarenal mass lesions (adrenal neuroblastoma, adrenal hemorrhage, and subdiaphragmatic extralobar pulmonary sequestration). The author describes the imaging approach, imaging appearance and differentiating features of tumors, and differences between fetal and childhood appearances of tumors.

Imaging manifestations of congenital mesoblastic nephroma

OBJECTIVE

Congenital mesoblastic nephroma (CMN) is a rare renal tumor mainly observed in infants and young children. This study aims to analyze the imaging manifestations of CMN to improve the understanding of the disease.

METHODS

The imaging manifestations and clinical records of all pediatric patients with CMN admitted to our hospital over the last 7 years were retrospectively analyzed. The diagnosis of CMN was confirmed by postoperative pathology. All patients underwent computed tomography (CT) scans; 2 patients additionally underwent magnetic resonance imaging (MRI) scans (including one prenatal MRI scan).

RESULTS

We evaluated 10 pediatric patients (6 males and 4 females) aged 7 days to 12 months (median age: 4 months) with CMN located on the left kidney in six cases and the right kidney in four cases. The CT imaging manifested as solid lesions (5 cases), solid-cystic lesions with solid predominance (4 cases), or solid-multicystic lesions with cystic predominance (1 case). Enhanced CT showed moderately and heterogeneously enhanced solid component and intracystic septations at the corticomedullary phase that were further enhanced at the nephrographic phase, although their CT values were still lower than those of the renal parenchyma. The "double-layer sign" were seen in 4 cases of classic type of CMN, and the "intratumor pelvis sign" were seen in 9 cases that include 5 classic, 3 cellular and 1 mixed type of CMN. In the 2 patients who underwent MRI, the scans showed solitary masses. The lesions had hypointense signals on the T1WI sequence and isointensity or slightly lower-intensity signals than the surrounding renal parenchyma on the fluid-sensitive sequences, whereas the lesions showed hyperintense signals on the diffusion-weighted imaging (DWI) sequence.

CONCLUSIONS

The imaging manifestations of CMN are closely correlated with the pathological subtype and have certain characteristics. The "double-layer sign" was seen with most classic type CMN, and "intratumor pelvis sign" was seen in 90% cases.

Prenatal diagnosis of congenital mesoblastic nephroma: a case with poor prognosis

Congenital mesoblastic nephromais a rare tumour found in neonates, with a very small number of cases diagnosed prenatally. We report a case of a fetal renal tumour suspected at 28 weeks' gestation on routine ultrasound. Prenatal follow-up revealed a severe polyhydramnios at 32 weeks' gestation subsequent amniodrainage was undertaken. She delivered at 34+5 weeks' gestation, after spontaneous premature rupture of membranes.

Specific computed tomography imaging characteristics of congenital mesoblastic nephroma and correlation with ultrasound and pathology

INTRODUCTION

Congenital mesoblastic nephroma (CMN) is a common solid renal tumor in the neonate. Congenital mesoblastic nephroma can be divided into classic, cellular, and mixed types. The prognosis of CMN is very optimistic. But CMN can easily be misdiagnosed as the other malignant renal tumors by radiology. However, no studies have described the computed tomography (CT) imaging appearance of CNM in detail. The objective of this study is retrospective analyses of the multislice CT characteristics of CMN and their corresponding ultrasound findings and pathology.

METHODS

This retrospective study reviewed the enhanced CT images of the CMNs and other renal tumors in children younger than 1 year in the past 10 years from the First Affiliated Hospital of Sun Yat-sen University. Two radiologists had noted the CT imaging characteristics of these images. t-test and Fisher's exact test were used in the comparison of imaging characteristics between the CMNs and other renal tumors.

RESULTS AND DISCUSSION

Compared with other malignant renal tumors, the CMNs tend to appear as smaller round masses without clear coverage or clear boundary with the kidney in CT images (P < 0.01). The intratumor pelvis and the double-layer sign are the specific characteristics of CMNs (P < 0.01). The gender, quality of tumor (solid or solid-cystic), character of enhancement (homogeneous or heterogeneous enhancement), peri-renal hemorrhage, or peripheral lymph node enlargement showed no statistical significance (P > 0.05) between CMNs and other renal tumors. The appearances of CMN with classic components in the CT images are relevant to the pathological findings. The intratumor pelvis is caused by the classic components of CMN growing to encapsulate the pelvis. The double-layer sign in CT image correlates with the specific hypoechoic ring in ultrasound, which is caused by the slow blood flow and delay contrast agent filling in the blood sinus located in the peripheral part of the tumor. The differential diagnosis of CMN should include the other solitary renal tumors such as Wilms' tumor, clear-cell sarcoma of the kidney, and rhabdoid tumor of the kidney.

CONCLUSION

The unclear coverage and unclear boundary with the kidney, the intratumor pelvis, and double-layer sign after contrast were specific CT imaging characteristics of CMN.

The extraordinary challenge of treating patients with congenital rhabdoid tumors-a collaborative European effort

BACKGROUND

Congenital rhabdoid tumors are rare and highly aggressive malignancies. In general, patients are considered to be incurable and are often treated using an exclusive, primarily palliative approach.

METHODS

A prospective and retrospective collection of 42 patients from the European Rhabdoid Registry (EU-RHAB), France and Moscow (2006-2016) diagnosed within the first 28 days of life was evaluated. Genetic and clinical reference evaluation included SMARCB1 and/or SMARCA4 (fluorescence-in-situ-hybridization, multiplex ligation-dependent probe amplification, and sequencing) mutation analysis and immunohistochemistry. Forty-eight percent (20/42) of patients were treated according to the EU-RHAB therapy, 7% (3/42) according to the pilot approach Rhabdoid 2007, 33% (14/42) with individual schedules, and 12% (5/42) received no chemotherapy at all.

RESULTS

Forty point five percent (17/42) of patients presented with extracranial rhabdoid tumors, 33.5% (14/42) with rhabdoid tumors of the central nervous system (atypical teratoid/rhabdoid tumor), and the remainder 26% (11/42) demonstrated synchronous tumors. Metastases at diagnosis were present in 52% (22/42) of patients. A germline mutation was detected in 66% (25/38) and was associated with a poor prognosis (4.2 ± 4.1% vs. 48 ± 16.4%, P < 0.00005). A gross total resection (GTR) was realized in 17%. A GTR (42.9 ± 18.7% vs. 4.9 ± 4.3%, P = 0.04), therapy according to a standardized approach (20.9 ± 8.7% vs. 7.1 ± 6.9 %, P = 0.0018), and a complete remission (CR) (23.6 ± 9.8% vs. 1.3 ± 3.6%, P = 0.04) were significant prognostic factors.

CONCLUSIONS

The management of patients with congenital rhabdoid tumors requires a major multidisciplinary effort. In many instances, cure is not possible and a palliative approach is warranted. Our data indicate a positive impact of standardized therapeutic approaches on survival, making a tailored approach toward affected patients and their families mandatory.

Renal Tumors in Children Younger Than 12 Months of Age: A 65-Year Single Institution Review

Wilms tumor (WT) is the most prevalent pediatric renal tumor and most commonly occurs between ages 1 and 5 years. Data are lacking on children younger than 12 months with renal tumors. The cancer registry at the authors' institution was queried to identify patients 12 months and younger with renal masses. Demographics, clinical presentation, histopathology, stage, and survival outcomes were reviewed. The most common presenting symptoms included an asymptomatic abdominal mass (73%) and hematuria (9%). Histopathology revealed WT in 73% of patients, mesoblastic nephroma in 20%. Of those infants younger than 1 month of age, mesoblastic nephroma was the most common histopathology (68%). The 5-year overall survival (OS) was 93%, and 5-year event-free survival (EFS) was 93% for the entire group. For patients with WT, 5-year OS was 88% and 5-year EFS was 83%. Outcomes for congenital mesoblastic nephroma were excellent with 5-year OS and EFS of 100%. Reasons for good prognosis may be multifactorial and may include frequent well child checks in the first year of life and favorable histology. Patients in this age group are more likely to be classified as very low risk and may be treated with surgical resection alone.

Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 1. The 1st Decade: From the Radiologic Pathology Archives

Wilms tumor is the second most common pediatric solid tumor and by far the most common renal tumor of infants and young children. As most tumors are large at presentation and are treated with nephrectomy, the role of imaging is primarily in preoperative planning and evaluation for metastatic disease. However, with treatment protocols increasingly involving use of preoperative (neoadjuvant) chemotherapy (the standard in Europe) and consideration of nephron-sparing surgery, the role of imaging is evolving to include providing initial disease staging information and a presumptive diagnosis to guide therapy. Differential diagnostic considerations include lesions that are clinically benign and others that require more intensive therapy than is used to treat Wilms tumor. In part 1 of this article, the unique histologic spectrum of renal neoplasms of infants and young children is reviewed with emphasis on radiologic-pathologic correlation. Part 2 will focus on renal tumors of older children and adolescents.

Management of mixed type congenital mesoblastic nephroma: Case series and review of the literature

Congenital mesoblastic nephroma (CMN) is the most common renal tumor of infancy; however, it occurs infrequently with an incidence of 1 : 125,000. The cellular and classical variants are the most common subtypes of tumors, with a mixed variant occurring infrequently. We describe two cases of mixed variant CMN, which presented within days of each other differing in their clinical behavior. The first case followed a typical course, previously described in the literature, while the other deviated significantly. Traditionally, CMN presents as large abdominal mass in the neonatal period associated with a paraneoplastic syndrome, which can result in hypertension or hypercalcemia. Surgical resection is curative in most cases and long-term prognosis is excellent. Hypertension rarely persists after removal of the tumor, but remained in one of our two patients.

Congenital Mesoblastic Nephroma Presenting With Refractory Hypertension in a Premature Neonate: A Case Study

The most common nonencapsulated solid renal tumor in the neonatal period is congenital mesoblastic nephroma. Mesoblastic nephroma is a solid lesion originating within or extending from the renal parenchyma. These tumors proliferate rapidly, typically within 3-6 months after birth. Mesoblastic nephromas are stratified by classification as either classical (benign) or atypical (malignant); masses composed of both benign and malignant cells are also reported. The hallmark clinical manifestation of mesoblastic nephroma is a palpable abdominal mass, which may be accompanied by hypertension, hypercalcemia, hematuria, and polyuria. Differentiating between benign and malignant renal tumors is essential to invoke a timely, evidence-based management and treatment plan. With appropriate surgical intervention in a timely manner, prognosis is excellent and mesoblastic nephroma is considered curable. We present a case involving a premature infant with congenital mesoblastic nephroma with discussion of embryology, pathophysiology, diagnostic, management, and prognostic implications for the neonate and family.

The Value of Mitotic Count and Ki67 Proliferation Index in Congenital Mesoblastic Nephroma

OBJECTIVE

We aimed to define the histopathologic features and proliferative rate of congenital mesoblastic nephroma (CMN) as a risk factor for recurrence.

METHODS

Fourteen cases of CMN among 138 registered pediatric renal tumors were retrospectively reviewed. The prognostic impact for mitotic rate and Ki67 index was investigated.

RESULTS

There were four (28.6%) classic, six (42.9%) cellular, and four (28.6%) mixed type CMNs, with average Ki-67 counts of 16.75% in the classic CMN, and 53.2% in the tumors with cellular components (both mixed and cellular CMNs). Twelve patients (85.7%) were aged less than six months. Tumors with cellular component showed significantly larger tumor diameter and higher Ki-67 index (p = 0.015 and p = 0.016, respectively). The patient with cellular CMN, whose tumor showed the highest mitotic rate (4.9/HPF), but not the highest Ki67 index (57.4%), died of recurrent disease with distant metastasis.

CONCLUSION

Proliferative markers-mitotic count and Ki67 index-have limited value to predict recurrence or metastasis in CMNs with a cellular component.

[Radiological evaluation of congenital tumors]

In this article, we consider tumors that are diagnosed during pregnancy or in the first three months of life. This is a heterogeneous group of neoplasms with special biological and epidemiological characteristics that differentiate them from tumors arising in children or adults. In the last two decades, the prenatal detection of congenital tumors has increased due to the generalized use of prenatal sonographic screening. Advances in imaging techniques, especially in fetal magnetic resonance imaging, have enabled improvements in the diagnosis, follow-up, clinical management, and perinatal treatment of these tumors. This image-based review of the most common congenital tumors describes their histologic types, locations, and characteristics on the different imaging techniques used.

Upper urinary tract anomalies and perinatal renal tumors

Congenital anomalies of the upper urinary tract are common and frequently diagnosed on prenatal ultrasound. In the absence of infection, these anomalies are often asymptomatic. This article reviews key features and long-term implications to assist in discussions with families. In contrast, a perinatal renal tumor is rare but extremely alarming. This update on the most common tumors and their treatment is useful in reassuring parents that most infants, after primary surgical resection, are cured without adjuvant therapies. To understand renal agenesis and other congenital renal malformations and their associated anomalies, a brief review of normal renal development is presented.

Preclinical evaluation of engineered oncolytic herpes simplex virus for the treatment of pediatric solid tumors

Recently, investigators showed that mice with syngeneic murine gliomas that were treated with a neuroattenuated oncolytic herpes simplex virus-1 (oHSV), M002, had a significant increase in survival. M002 has deletions in both copies of the γ134.5 gene, enabling replication in tumor cells but precluding infection of normal cells. Previous studies have shown antitumor effects of other oHSV against a number of adult tumors including hepatocellular carcinoma and renal cell carcinoma. The purpose of the current study was to investigate the oncolytic potential of M002 against difficult to treat pediatric liver and kidney tumors. We showed that the oHSV, M002, infected, replicated, and decreased cell survival in hepatoblastoma, malignant rhabdoid kidney tumor, and renal sarcoma cell lines. In addition, we showed that in murine xenografts, treatment with M002 significantly increased survival and decreased tumor growth. Finally, these studies showed that the primary entry protein for oHSV, CD111 (nectin-1) was present in human hepatoblastoma and malignant rhabdoid kidney tumor specimens. We concluded that M002 effectively targeted these rare aggressive tumor types and that M002 may have potential for use in children with unresponsive or relapsed pediatric solid tumors.

Neonatal cancer

Neonatal cancer is rare and comprises a heterogeneous group of neoplasms with substantial histological diversity. Almost all types of paediatric cancer can occur in fetuses and neonates; however, the presentation and behaviour of neonatal tumours often differs from that in older children, leading to differences in diagnosis and management. The causes of neonatal cancer are unclear, but genetic factors probably have a key role. Other congenital abnormalities are frequently present. Teratoma and neuroblastoma are the most common histological types of neonatal cancer, with soft-tissue sarcoma, leukaemia, renal tumours, and brain tumours also among the more frequent types. Prenatal detection, most often on routine ultrasound or in the context of a known predisposition syndrome, is becoming more common. Treatment options pose challenges because of the particular vulnerability of the population. Neonatal cancer raises diagnostic, therapeutic, and ethical issues, and management requires a multidisciplinary approach.

[Malignant neoplasms in the neonate]

Cancer in children has characteristics that differentiate it from other types reported in later ages. Overall survival at 3 years is up to 70% depending on the tumor studied. Major organs and systems affected are the hematopoietic system, central nervous system and sympathetic and mesenchymal tissues. The increased incidence of neonatal tumors observed in this and other studies is based on the increasing number of solid tumors (teratomas and neuroblastomas) because cases of central nervous system tumors and leukemias have remained constant. Ultrasonography is the first line of approach and can detect up to 70% of fetal anomalies. The physiology of the newborn causes the necessary multidisciplinary treatment in neoplastic disease to be modified substantially in this age group to avoid toxicity and sequelae. The most common treatment is surgery. Achieving timely diagnostic treatment options are effective in improving the survival of these patients.

Renal and hepatic tumors in the neonatal period

Renal and hepatic tumors in neonates are extremely rare. Nevertheless it is important for clinicians to be familiar with them. Both renal and hepatic neonatal tumors are heterogeneous collections of several tumor types. Some renal and hepatic tumors are benign and may require no interventions whereas others can be associated with significant morbidity and even mortality and may require multimodality treatment. Early diagnosis and initiation of the proper treatment plan is crucial for achieving the best outcomes for these rare tumors in this vulnerable population.

Mesoblastic nephroma: a report of the United Kingdom Children's Cancer and Leukaemia Group (CCLG)

BACKGROUND

Mesoblastic nephroma (MN) is a rare tumour which occurs mainly in early infancy and for which primary nephrectomy is the treatment of choice. This study aimed to assess surgical complications and outcomes in this patient group and to re-evaluate the age threshold of 6 months for recommending primary nephrectomy.

PROCEDURE

A retrospective file review of all cases of MN registered in UK Children's Cancer and Leukaemia Group renal tumour trials between October 1991 and March 2008. Data from the trials were compared with data held by the National Registry of Childhood Tumours, Oxford.

RESULTS

Forty-seven (3.5%) confirmed cases of MN were found among 1346 registered renal tumours. Median age at diagnosis was 30 days (range birth-3.8 years). MN was significantly more common in the first 3 months of life compared to between 3 and 6 months (33 vs. 2 cases). Seven cases occurred between 6 months and 1 year and only five cases occurred beyond 1 year of age. There was a significant difference in the age of diagnosis by histological subtype. There were 11 complications in the series; no registered patient developed a recurrent tumour; and all were alive at last follow-up.

CONCLUSIONS

Outcome for children with MN is excellent at all ages, with little indication for adjuvant chemotherapy. Children presenting at <3 months of age, should be treated by primary nephrectomy. In those presenting aged >3 months, alternative diagnoses should be considered, especially in the presence of surgical risk factors.

Intrauterine demise due to congenital mesoblastic nephroma in a fetus conceived by assisted reproductive technology

OBJECTIVE

To report a case of antenatally diagnosed congenital mesoblastic nephroma in an assisted reproductive technology (ART) conception.

DESIGN

Case report.

SETTING

Tertiary care university-affiliated hospital.

PATIENT(S)

Fetus of 26-weeks' gestation with antenatally diagnosed large abdominal tumor.

INTERVENTION(S)

ART with transfer of cryopreserved embryo.

MAIN OUTCOME MEASURE(S)

Postmortem examination.

RESULT(S)

Examination revealed a congenital mesoblastic nephroma, mixed classic and cellular type, with marked intratumoral hemorrhage and associated hydrops. The marked fetal erythroblastosis was suggestive of fetal response to pronounced anemia. Intrauterine demise is attributed to fetal intratumoral hemorrhage and early nonimmune hydrops secondary to a large congenital mesoblastic nephroma.

CONCLUSION(S)

This is the third reported case of congenital mesoblastic nephroma in an ART conception. Whether the association between mesoblastic nephroma and ART is coincidental or causative remains to be determined.

Congenital tumors: imaging when life just begins

Background

The technical developments of imaging methods over the last 2 decades are changing our knowledge of perinatal oncology. Fetal ultrasound is usually the first imaging method used and thus constitutes the reference prenatal study, but MRI seems to be an excellent complementary method for evaluating the fetus. The widespread use of both techniques has increased the diagnosis rates of congenital tumors. During pregnancy and after birth, an accurate knowledge of the possibilities and limits of the different imaging techniques available would improve the information obtainable, thus helping the medical team to make the most appropriate decisions about therapy and to inform the family about the prognosis.

Conclusion

In this review article, we describe the main congenital neoplasms, their prognosis and their imaging characteristics with the different pre- and postnatal imaging methods available.

Neonatal renal tumours

Neonatal renal tumours are rare, with only 7% of all neonatal tumours arising from the kidney. Presentation is usually as a flank mass or as a coincidental finding on either antenatal or postnatal ultrasound. Mesoblastic nephroma is the most common tumour to be found at this age, but Wilms' tumour and other malignant and benign tumours occur. Cross sectional imaging is useful to delineate the extent of the disease. Given the low malignant potential of these tumours, treatment is by radical nephroureterctomy, except in cases with bilateral disease or syndromic patients with a high incidence of metachronous tumours. Chemotherapy is rarely indicated. Survival is generally excellent for all tumour types in this age group, the exception being malignant rhabdoid tumour of the kidney which may have metastases at presentation.

Fetal and neonatal rhabdoid tumor

PURPOSE

Few studies have focused on the behavior of rhabdoid tumor (RT) in the fetus and neonate. The purpose of this review is to show that perinatal RTs are associated with unusual findings and a poor prognosis.

METHODS

The author conducted a 40-year systematic review of the literature. Clinical presentation, pathology, management, and outcome of 72 fetuses and neonates with RTs are discussed.

RESULTS

Seventy-two fetuses and neonates presented with RTs detected prenatally (n = 12) and during the neonatal period (n = 60). The review consisted of 3 main groups: extrarenal noncentral nervous system (CNS) RT, renal RT, and CNS RT. There were some group differences in survival: extrarenal non-CNS RT (3/33 or 9.1%), renal RT (2/27 or 7.4%), and CNS RT (2/12 or 16.7%). Metastatic RT was present at diagnosis in more than half the patients (41/72 or 57%) who had a survival of 2.3%. The overall survival was 9.7%. For statistical results, there was no significant difference in survival among the 3 groups by type of tumor (P = .692). chi(2) analysis for survival with and without metastases was not valid due to small sample size.

CONCLUSIONS

The review shows that extrarenal RT was more common than either renal RT or CNS RT groups that is different than that observed in older individuals. Concomitant brain tumors were found in almost a third of fetuses and neonates. The CNS involvement occurred more often in patients with renal RT than in those with extrarenal RT. Metastatic disease at diagnosis was noted in more than half of the patients. Higher stage and presence of a CNS tumor were significant determinants in survival.