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.

Congenital mesoblastic nephroma: a single-centre series.

BACKGROUND: Congenital mesoblastic nephroma is a rare disease. Treatment is surgical in the first instance. Chemotherapy has traditionally been thought not to have a role. Recent literature suggests a 50% mortality rate for recurrent/metastatic disease. MATERIALS AND METHODS: This study is a retrospective case review of prospectively collected data. Demographics, histopathology, treatment, outcomes and follow up were reviewed. RESULTS: Nine patients, 6 male and 3 female, were included. The median age at presentation was one month (range 0-7 months); follow-up was for a median of 21.5 months (range 16-79 months). Two patients had mixed and classical subtypes and the other five had the cellular subtype. Surgery was completed by an open procedure in eight patients and laparoscopically in one. There were three recurrences; two were local and one was pulmonary. Recurrences were treated with a combination of chemotherapy, radiotherapy and surgery. One patient with recurrent disease died from acute-on-chronic respiratory failure secondary to lung irradiation but was disease free. The other eight are disease free, alive and well with no sequelae at latest follow-up. CONCLUSIONS: Surgery remains the mainstay of management with chemo- and radiotherapy reserved for unresectable tumours or adjuvant management of recurrent disease. Specimen-positive margins are not an indication for instituting chemotherapy. The tyrosine kinase pathway seems to be a potential target for future chemotherapeutic agents although it is too early to assess how that will impact on the management of congenital mesoblastic nephroma.

Cellular mesoblastic nephroma in infants and children: Report of four cases and review of the literature.

BACKGROUND: Cellular mesoblastic nephroma is rare after infancy, and there are many controversial reports about its clinical presentation and treatment as well as outcome in infants, young children, and adolescents. OBJECTIVES: In this report, we will discuss our experience with four cases of cellular mesoblastic nephroma presented from infancy to childhood (from 18 months of age to 11 years of age). CASES: During 10 years, we had the experience of 4 cases of pediatric renal tumor with the diagnosis of cellular mesoblastic nephroma, which have been followed between 1 year and 6 years. There were three male and one female patients with the age of 1.5, 2, 2, and 11 years. These tumors showed variable characteristics according to the number of mitosis, proliferative rate, necrosis, immunohistochemical markers, and metastatic potential; however, despite of all of these variabilities, all of these patients have done well and all have been well at the end of study. CONCLUSION: Pediatric renal tumors with the histologic diagnosis of cellular mesoblastic nephroma have good outcome even with metastasis, mitosis, and high proliferative rate.

[Solid pediatric tumors : A brief survey of the rarity cabinet]. / Solide Kindertumoren : Ein Streifzug durch das Raritätenkabinett.

Solid tumors in childhood are extremely rare entities, which are usually treated in specialized centers. Diagnosis and therapy are carried out according to a joint European protocol, whereby the pathological evaluation and therapy are carried out according to international guidelines. For the correct diagnosis and/or therapy of most tumors, analysis of specific genetic changes is mandatory; therefore, tumors have to be adequately sampled for parallel genetic analysis during the pathological work-up. A second opinion reference of the histopathological assessment is part of the international guidelines. Neuroblastomas, congenital mesoblastic nephromas and rhabdoid tumors are examples of solid tumors in childhood that are not restricted to one organ and occur exclusively during childhood.

Current Management of Fetal and Neonatal Renal Tumors.

Fetal and neonatal renal tumors are rare. Nevertheless, in-depth understanding of their features can lead to early recognition and appropriate treatment, ultimately benefiting outcome. Despite the many obvious similarities, important distinctions exist between these tumors and their counterparts in older children. Likewise, some important distinctions exist between fetal tumors on the one hand and neonatal tumors on the other. In this article, we review the pertinent features of fetal and neonatal renal tumors and specifically point out the important individualities in their clinical management.

Cellular mesoblastic nephroma with liver metastasis in a neonate: prenatal and postnatal diffusion-weighted MR imaging.

Congenital mesoblastic nephroma (CMN) is the most common renal tumor in the first year of life. Here, we present unique findings of cellular variant CMN seen on prenatal and postnatal MRI with diffusion-weighted imaging (DWI).The mass was well-visualized on prenatal MR DWI with diffusion restriction in the solid portions. After excision of the mass, follow-up whole body MRI with DWI helped identify local tumor recurrence with suspicious liver metastasis. This hepatic lesion also showed diffusion restriction.

Cellular congenital mesoblastic nephroma: case report.

INTRODUCTION: Congenital Mesoblastic Nephroma (CMN) is a rare pediatric renal tumor. It comprises two histological subtypes, namely classic and cellular, with the second accounting for two thirds of all cases and being more often associated with poor prognosis. It remains a diagnostic challenge for pathologists due to its similarity with other more frequent pediatric kidney neoplasms. CASE REPORT: We describe the case of a 2-year- old girl who presented with a left renal mass. After nephrectomy, the specimen analysis showed, on gross examination, an extensive, granular and whitish tumor lesion occupying almost the entire kidney, invading the renal sinus, capsule and perirenal fat, with areas of hemorrhage and necrosis. Histologically, it was characterized by ovoid spindle cells, mitoses and no cell atypia, which led to a diagnosis of cellular mesoblastic nephroma. Adjuvant chemotherapy was carried out, but tumor recurrence occurred in the first year, presenting as an unresectable tumor that did not respond to adjuvant chemotherapy and the patient died at 4 years of age. DISCUSSION: The cellular variant tends to be more aggressive, with a survival rate of 85% versus 100% for the classic variant. Recurrence generally occurs in the first year, particularly with the cellular variant.

Nefroma mesoblástico congênito subtipo celular: relato de caso / Cellular congenital mesoblastic nephroma: case report

INTRODUÇÃO: Nefroma Mesoblástico Con-gênito é uma rara neoplasia renal pediátrica. Apresenta dois subtipos histológicos, clássico e celular, sendo o último de pior prognóstico e responsável por aproximadamente dois terços dos casos. Esse tumor ainda é um desafio diagnóstico aos patologistas devido à similaridade com outras neoplasias pediátricas renais mais frequentes. RELATO DO CASO: Criança do gênero feminino, 2 anos e 9 meses de idade, foi encaminhada a serviço médico com referência em oncologia apresentando massa renal à esquerda. Após nefrectomia, o estudo do espécime mostrou, macroscopicamente, extensa área tumoral granular, brancoacinzentada, ocupando aproximadamente todo o rim, invadindo seio renal, cápsula e gordura perirrenal, com áreas de hemorragia e necrose. Histologicamente, caracterizava-se pela presença de células fusiformes e mitoses, sem atipias celulares. O diagnóstico foi de Nefroma Mesoblástico Congênito subtipo celular e a paciente foi submetida a quimioterapia. Durante o primeiro ano de tratamento, houve recidiva do tumor, apresentando-se irressecável e sem resposta a nova quimioterapia. A paciente foi a óbito aos 4 anos de idade. DISCUSSÃO: O subtipo celular do nefroma mesoblástico tende a ser mais agressivo, apresentando uma taxa de sobrevivência de 85 por cento, comparada com 100 por cento para a variante clássica. Geralmente, a recorrência ocorre no primeiro ano de tratamento, principalmente quando o subtipo é o celular.

INTRODUCTION: Congenital Mesoblastic Nephroma (CMN) is a rare pediatric renal tumor. It comprises two histological subtypes, namely classic and cellular, with the second accounting for two thirds of all cases and being more often associated with poor prognosis. It remains a diagnostic challenge for pathologists due to its similarity with other more frequent pediatric kidney neoplasms. CASE REPORT: We describe the case of a 2-year- old girl who presented with a left renal mass. After nephrectomy, the specimen analysis showed, on gross examination, an extensive, granular and whitish tumor lesion occupying almost the entire kidney, invading the renal sinus, capsule and perirenal fat, with areas of hemorrhage and necrosis. Histologically, it was characterized by ovoid spindle cells, mitoses and no cell atypia, which led to a diagnosis of cellular mesoblastic nephroma. Adjuvant chemotherapy was carried out, but tumor recurrence occurred in the first year, presenting as an unresectable tumor that did not respond to adjuvant chemotherapy and the patient died at 4 years of age. DISCUSSION: The cellular variant tends to be more aggressive, with a survival rate of 85 percent versus 100 percent for the classic variant. Recurrence generally occurs in the first year, particularly with the cellular variant.

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.

Part II: Treatment of primary malignant non-Wilms' renal tumours in children.

Renal-cell carcinoma, clear-cell sarcoma, (congenital) mesoblastic nephroma, rhabdoid tumour, and renal medullary carcinoma form a heterogeneous group of childhood renal malignancies known as non-Wilms' tumours. Progress has been slow in improving the management of these tumours to decrease morbidity and increase survival. However, greater cooperation between national and international centres should engender specialisation, and an increased knowledge of the molecular biology of these tumours will inevitably lead to substantial progress over the next decade. This review is the second of two parts: the first part provided an updated review of the clinical presentation, imaging, and pathology of non-Wilms' tumours and this second part provides an updated review of the treatment of these tumours.

Part I: Primary malignant non-Wilms' renal tumours in children.

Non-Wilms' tumours form a small heterogeneous group of clinically significant renal malignancies in children, including renal-cell carcinoma, clear-cell sarcoma, (congenital) mesoblastic nephroma, rhabdoid tumour, and renal medullary carcinoma. Good progress has been made in the assessment of these tumours, which has led to a greater understanding of the molecular changes that occur in their development. This review is the first of two parts, and provides an updated review of the clinical presentation, imaging, and pathology of these tumours.

A case of fetal congenital mesoblastic nephroma with oligohydramnios.

Although congenital renal tumors are rare, congenital mesoblastic nephroma (CMN) is the most common renal tumor in early infancy. It is non-metastatic, well differentiated, amenable to surgical removal, and carries a good prognosis. Polyhydramnios has been detected in most of the published cases of CMN. However, we experienced a rare case of fetal CMN associated with oligohydramnios. A 28-yr old woman at 34 weeks of gestation was referred to our hospital for oligohydramnios and a fetal abdominal mass. An ultrasonography revealed a huge, well-encapsulated mass arising from the right kidney. An emergency cesarean section was performed due to fetal distress. After birth, despite intensive neonatal care, the baby died because of renal failure, disseminated intravascular coagulopathy, pulmonary edema, together with other problems.

An association of pleuropulmonary blastoma and cystic nephroma: possible genetic association.

The association of pleuropulmonary blastoma and cystic nephroma is an uncommon entity, with only 4 cases of such an association in the same patient described in English literature. We report a 5th histologically documented case in a 32-month-old boy. The boy underwent a pulmonary biopsy that showed a pleuropulmonary blastoma and a nephrectomy that showed a cystic nephroma. The pleuropulmonary mass showed an important regression with postbiopsy chemotherapy, allowing subsequent tumorectomy. To date very little is known about this rare entity, and a genetic link between these 2 tumors is hypothesized.

Mesoblastic nephroma--a report from the Gesellschaft fur Pädiatrische Onkologie und Hämatologie (GPOH).

BACKGROUND: Surgery alone is the appropriate first-line treatment for patients with mesoblastic nephroma (MN). Nevertheless, there are reports of local recurrences and metastasis, especially in the cellular subtype. The authors evaluated the outcome of patients with MN who were enrolled in either the International Society of Pediatric Oncology (SIOP) 93-01/GPOH or the SIOP 2001/GPOH Nephroblastoma Study and Trial. METHODS: In total, 50 patients with MN were analyzed. Eleven patients were suspected antenatally of having a renal tumor. The median age at diagnosis was 18.5 days. Central pathologic review was performed for all specimens. The median observation time was 4.2 years. RESULTS: Forty-five patients underwent initial surgery. Five patients older than 6 months received preoperative chemotherapy. Twenty-nine tumors were classic MN, and 21 tumors were cellular MN. Nine patients had a Stage III MN, 5 of those patients had tumor ruptures, and 8 had positive surgical margins. After they underwent nephrectomy, 40 patients received no further treatment. For the entire group, event-free survival (EFS) (94%) and overall survival (OS) (95%) were excellent. Patients with a cellular MN, patients with age 3 months or older, and patients with Stage III MN had lower EFS. Three patients developed recurrent disease, and 2 of those patients died. Metastases to the brain, lung, and liver were observed in 1 patient. CONCLUSIONS: Radical nephrectomy with accurate surgical-pathologic staging is the standard of care for children with MN. Nonetheless, a subgroup of patients with MN (Stage III cellular MN in patients age 3 months or older) tends to develop recurrences more often. Further prospective studies will be needed to verify this finding and should help determine whether these patients may benefit from adjuvant therapy.

[Nephroblastoma in children aged less than 6 months at diagnosis]. / Nowotwory nerek u noworodków i niemowlat w pierwszych 6 miesiacach zycia.

UNLABELLED: We present the results of treatment of kidney tumours in newborns and infants aged less than 6 months, in the years 1993-2000, from the Nephroblastoma Committee of the Polish Paediatric Group of Solid Tumours (PPGGL). We have analysed the diagnostic and treatment results in the group of 31 children aged 0 to 6 months. For 19 children registered between 1993 and 1996, event-free survival (EFS) and overall survival (AS) were assessed. Among 450 children registered between 1993 and 2000 by PPGGL and treated for kidney tumours, there were 31 (7.1%) newborns and infants aged below 6 months. The accuracy of diagnosis based on imaging studies was 97%. Only in one child the initial diagnosis of kidney tumour was not confirmed; cystic degeneration of kidney was finally established. The tumours removed during surgery were small, with average size 213 cm3, and in half of the cases the size of the tumour did not exceed 165 cm3. Primary complete excision of the tumour was performed in 21 children (67.7%). In 10 cases histopathology confirmed mesoblastic nephroma, in 19 cases nephroblastoma and in 2 cases sarcoma clarocellulare. In 10 infants (32.2%) with nephroblastoma delayed surgery preceded by chemotherapy was performed. Indications for initial preoperative chemotherapy comprised: tumour in a single kidney, tumour in a horseshoe kidney, preoperative diagnostic biopsy of the tumour and large tumour in neonates older than 3 months. In almost 70% of the children the stage of advancement was low (stage I and IIN-). Histopathology of excised tumours confirmed in 42% of cases low risk, and in 51.6% intermediate risk. Intraoperative complications occurred in 5 infants (16%). The tolerance of reduced chemotherapy by the infants was good. AS was 100%. ESF for the 19 children registered for nephroblastoma between 1993 and 1996 for all stages of advancement and types of histology was 94.75%. CONCLUSIONS: 1) Mesoblastic nephroma and low risk nephroblastoma are the most common tumours in children within the first three years of life. 2) The results of treatment of nephroblastoma in the youngest children (below 6 months of age) are the most favourable and represent world standards.3) Surgical complications in children operated primarily for nephroblastoma indicate the need of performing such operations in academic centres, specialised in newborn surgery. 4) In infants with extensive kidney tumours older than 3 months, primarily considered as inoperative, individual induction chemotherapy should be taken into account.

Perinephric cystic mesoblastic nephroma complicated by hepatic metastases: a case report.

Congenital mesoblastic nephroma (CMN) is a well-recognised renal tumour presenting in infancy, which has an excellent prognosis if completely excised. We describe the imaging appearances of an unusual, predominantly perinephric cystic CMN, with relative renal preservation but with retroperitoneal extension and bowel infiltration, which was complicated by hepatic metastases. To our knowledge, neither the appearance of the primary tumour nor the subsequent development of hepatic metastases has previously been reported. This appearance may represent a poor prognostic indicator for outcome. However, following partial hepatectomy, the patient remains disease-free at 1 year.

Cystic atypical mesoblastic nephroma.

Cystic variants of atypical mesoblastic nephromas are very rare. The present communication deals with two such cases encountered in 3- and 6-month-old patients. The literature is briefly reviewed. The need for proper diagnosis of this tumor to distinguish it from cystic nephroma and Wilms' tumor is highlighted.

Pediatric renal tumors.

A broad spectrum of renal tumors occurs in infants and children ranging from the benign cystic nephroma to the extremely aggressive malignant rhabdoid tumor of the kidney. A thorough understanding of these tumors is crucial to the optimal diagnosis and management of children with renal masses. The common renal tumors in infants and children are discussed and an orderly method for their evaluation is presented. Recent developments in the molecular biology of Wilms' tumor are outlined to provide insight into the origin of this tumor.

[Atypical mesoblastic nephroma with metastases right away?]. / Néphrome mésoblastique atypique avec métastases d'emblée?

The diagnosis of a metastatic kidney tumor arising in a 2-month infant is discussed between atypical mesoblastic nephroma and clear cell sarcoma. The precocity of distant metastases, their location in bone marrow, liver and thoracic soft tissues, and their association with myelofibrosis set up an original clinical presentation which seems to have never been described elsewhere. Treatment strategy with surgery of the primary followed by a polychemotherapy combining vincristin-etoposide-ifosfamide and the short term follow-up are reported.