[Multiloculated mesenteric and retroperitoneal tumour - lymphatic malformation - in a 4-year-old girl]. / Wielokomorowy guz krezki I prezestrzeni zaotrzewnowej - malformacja chlonna u czteroletniej dziewczynki.

Mesenteric cysts are rare and mostly benign abdominal tumours in children. Majority of them are lymphangiomas (lymphatic malformations). We diagnosed a broad, multiloculated mesenteric and retroperitoneal cyst, associated with intensive inflammation, in a 4-year-old girl. Surgical therapy was fully successful.

Intraspinal mesenchymal chondrosarcoma in a 14-year-old patient: diagnostic and therapeutic problems in relation to the review of literature.

Mesenchymal chondrosarcoma (MC) is an infrequent, highly malignant neoplasm of the soft tissues and bone. It is very rare in the pediatric age group, especially in the intraspinal location. Only 24 cases have been reported to date. The authors present a case of a 14-year-old boy with an intraspinal MC who died of the disease 50 months from the initial diagnosis and after the third local recurrence. The patient was treated with a combination of chemotherapy, radiotherapy, and surgery. The authors review the clinical presentation, diagnostics, and the efficacy of treatment of pediatric patients with MC reported in the literature from 1978 to 2010.

[Opsoclonus-myoclonus syndrome in a 2 year old boy with prenatally diagnosed retroperitoneal tumour]. / Zespol opsoklonie-mioklonie (the opsoclonus-myoclonus syndrome- OMS) u 2-letniego chlopca z rozpozpoznanym prenatalnie guzem przestrzeni zaotrzewnowej

Opsoclonus-myoclonus syndrome, also named Myoclonic Encephalopathy of Infants, Opsoclonus- Myoclonus Ataxia, Dancing Eyes - Dancing Feet Syndrome, Dancing Eyes Syndrome, Kinsbourne syndrome, is a rare, paraneoplastic or possibly post-viral chronic neurological disorder. The age of presentation ranges from 6 months to 3 years. In 50% of affected children the syndrome is associated with an underlying occult or clinically apparent neuroblastoma. In most patients the tumour is localized, small and well differentiated, with no NMYC gene copy number amplification. The syndrome may also occur after tumour resection or at relapse. The opsoclonus-myoclonus syndrome can occur in children without neuroblastoma, in such idiopathiccases, the onset of neurological symptoms is related to infection. It is assumed, that in idiopathic cases the syndrome could have developed in the course of neuroblastoma which had undergone a complete spontaneous regression. The most characteristic clinical features of opsoclonus-myoclonus syndrome are: opsoclonus, myoclonus, ataxia, irritability, mutism and sleep disturbances. The disease course is usually long-term with episodes of remission and relapses. Approximately 80% of children with opsoclonus-myoclonus syndrome suffer from mild to severe neurological handicaps, mainly cognitive impairment. The authors present a 2-year old boy with opsoclonus-myoclonus syndrome preceded by involution of prenatally documented retroperitoneal area tumour.

Thymic carcinoma in children: a report from the Polish Pediatric Rare Tumors Study.

BACKGROUND: Invasive thymomas and thymic carcinomas are rare tumors jointly accounting between 0.2% and 1.5% of malignancies in adults. They are usually at an advanced stage when diagnosed and have both high recurrence and poor survival rates. In this report, the aim is to explore our experience in the treatment of thymic carcinomas in Polish children. PROCEDURE: The clinical data of nine children with thymic carcinomas, treated between 1992 and 2008 in the Polish oncological and surgical centers was retrospectively analyzed. RESULTS: In five cases, presenting symptoms resulted from the compression of the respiratory ways by the mediastinal tumor. In two children paraneoplastic autoimmune syndromes were associated with thymic carcinoma. In accordance with the Masaoka classification, two patients had stage II, five had stage III, and two had stage IV of the disease. Diagnostic biopsy of mediastinal tumor was performed on eight patients and one underwent complete primary resection and subsequently received radiotherapy; he has passed 11 years since the conclusion of therapy. Six patients received multi-drug chemotherapy with or without steroids. Delayed surgery was performed in four children (R0-2, R1-1, and R2-1). After complete resection, one child received chemotherapy. In three patients, chemotherapy and radiotherapy was administered. Seven patients died, including six due to progression of the disease with the other as a result of complications following chemotherapy; only two patients classed at stage II remain alive. CONCLUSIONS: Most thymic tumors in pediatric patients are inoperable at diagnosis, which results in poor prognosis. Improved chemotherapy approaches are needed.

Factors predicting survival in childhood malignant and intermediate vascular tumors : retrospective analysis of the Polish and German cooperative paediatric soft tissue sarcoma study groups and review of the literature.

BACKGROUND: The rarity of malignant and intermediate vascular tumors in children means that little is known about their clinical course, optimal treatment, and variables predicting survival. METHODS: A total of 32 children with malignant vascular tumors (14 angiosarcomas [AS], 5 epithelioid hemangioendotheliomas, and 13 intermediate vascular tumors, including other hemangioendotheliomas plus adult-type hemangiopericytomas), registered in the German and Polish Paediatric Soft Tissue Sarcomas Study Groups, were treated following the Cooperative Weichteilsarkom Studiengruppe (CWS)-81, -86, -91, and -96 protocols. RESULTS: Male sex, AS histology, tumor size >5 cm, and T2 invasiveness were independent predictors of inferior 5-year overall survival, while AS histology and T2 invasiveness were predictors of inferior 5-year event-free survival. AS histology was the most important negative prognostic factor for overall survival and event-free survival. Completeness of primary tumor excision was a good prognostic factor for survival in univariate, but not multivariate, analysis. Local therapy (radiotherapy and delayed surgery) were provided to the minority of patients (28% and 38%, respectively) late in the course of disease (after a mean of 9 and 6 months, respectively) and did not prevent local relapses. Response to systemic treatment was poor (44%) and did not prevent local and distant relapses. CONCLUSIONS: The clinical course and outcome in childhood epithelioid HE seems to be similar to intravascular tumors and less aggressive than AS. RTX and delayed surgery should be performed more frequently and earlier in the disease course. An urgent need for modification of systemic therapy is needed because of the development of many metastatic and/or combined relapses and poor response to classic chemotherapy. The problem of effective therapy for childhood AS is the most appaling: 13 of 14 patients died of progression despite multimodal treatment.

[Treatment results of children with neuroblastoma: report of Polish Pediatric Solid Tumor Group]. / Wyniki leczenia dzieci ze zwojakiem zarodkowym wspólczulnym: wstepny raport Polskiej Pediatrycznej Grupy Guzów Litych.

Approximately 60 children aged 0-18 years are diagnosed of NBL each year in Poland. About 60% of all patients suffering from NBL have a chance for durable cure. Unfortunately the prognosis for patients within the high-risk group accounting for more than 50% of all NBL patients remains poor despite the introduction of more intensive chemotherapy regimens with radical surgery procedures and megachemotherapy with subsequent stem cell transplantation. Only one third of patients in this group can be cured. To improve the treatment results of the high-risk patient group and to decrease the rate of therapy related side effects current European treatment protocols have been introduced systematically in Poland. In February 2009 information about 389 patients (age 0.1-16.5 years) diagnosed between 2001 and 2008 were obtained. Results of therapy of 319 patients who started treatment from 2001 to 2007 were analyzed. Between 104 infants and 215 children over 1 year of age, stage 4 of disease was found in 25% and 54.5%, respectively. In this period additionally to European treatment protocols, two another protocols were used. Satisfactory treatment results were obtained in 104 infants (5-year event free survival /EFS/=82.6%), irrespective of the type of treatment protocol. Over 5-year EFS for children over 1 year of age in 1, 2 and 3 stage of disease was: 100%, 86.3% and 64.5%, respectively. On the contrary, 107 patients with 4 stage of disease achieved the 5-year EFS of 27% only. Treatment results obtained in patients treated according to the European HR-NBL-1/ESIOP protocol were better than for patients treated according to other treatment protocols (5-year EFS: 31.1% and 16.4%, respectively), but difference between these groups was not significant. Between 2001 and 2007 data reporting increased to 81% from 19% noted earlier. Unfortunately, results of treatment for children over 1 year of age remain still unsatisfactory. That is why there is a need of improvement of modern, unified treatment realization as well as better data reporting. For realization of these aims adequate financial support is essential.

Suitability of imaging methods (X-ray, CT, MRI) in the diagnostics of Ewing's sarcoma in children - analysis of own material.

BACKGROUND: Ewing sarcoma is a malignant, small round cell bone tumor, presenting predominantly in children and adolescents. Ewing sarcoma may develop in every bone; diaphyses of long bones, ribs and flat bones are the main locations. Local and systemic clinical symptoms are nonspecific - pain, swelling, fever or ill-being. The aim of the study was to assess the role of radiography, computed tomography and magnetic resonance imaging in the analysis of bone lesions in children and young adults with Ewing sarcoma. MATERIAL/METHODS: Twenty-seven patients, aged between 1 year and 10 months, and 17 years and 2 months, with histologically verified Ewing sarcoma of the bone, referred to the Radiological Department of University Hospital No 6., John Paul II Upper Silesian Centre for Child Health Katowice, in the period from 1996 to 2007, were included in the study.Plain radiography was performed in every child, CT in 20 and MRI in 12 individuals. Tumour location, extension of the tumour, soft tissue mass, and periosteal reaction were taken into consideration in the evaluation of the lesion. In some cases, pathological features of the MRI and CT were compared. The prevalence of some radiological features was compared to the literature data. RESULTS: THE MOST COMMON SITE OF TUMOR WAS: ribs (6 children), femoral bone (6 children), pelvis (4 children) and tibia (3 children). In 2 children, a primary tumor was diagnosed in the spine (multifocal in 1 child). X-rays revealed: periosteal reaction in 17 children (63%), soft tissue involvement in 19 children (70%), permeative component in 16 children (59%), and sclerotic component in 5 children (19%). In 10 children (37%), periosteal reaction was not detected. The examination revealed: soft tissue calcifications in 7 cases (26%), a well-delineated focus of destruction within bones in 3 children (11%), cortical thickening in 4 children (15%), cortical destruction in 4 children (15%), saucerisation in 3 children (11%), bone expansion in 3 children (11%), pathological fracture in 2 children (7%), cystic component in 1 child (4%), and vertebra plana in 1 child (4%).Reaction of tumors after i.v. contrast administration, shown on CT, was visible in 16 children - it was useful for a better description of the tumor and extension of the mass within the soft tissue. All MRI examinations (12 children) showed a heterogenous mass with ill-defined borders and a violated cortex. Low signal intensity of the tumor in a T1-weighted image and high signal intensity in a T2-weighted image was shown as well. Heterogenous enhancement of signal intensity on T1-weighted images could be observed after i.v. contrast administration. MRI EXAMINATIONS SHOWED: tumor in an adjacent soft tissue in 11 children, and involvement of the epiphyseal plate or of the joint cavity in 6 children. CONCLUSIONS: X-ray and MRI are essential in diagnostics. CT examination is more useful to estimate periosteal reactions and destruction of bone and marrow cavity, especially in flat bones. However, to recognise a malignancy, it is necessary to perform a histopathological examination. In doubtful cases, the examination has to be verified as well.

Retrospective multi-institutional study on hemangiopericytoma in Polish children.

BACKGROUND: Pediatric hemangiopericytoma (HPC) is an extremely rare vascular tumor with little data available on its clinical course and management. METHODS: Fourteen children with HPC registered in Polish Pediatric Rare Tumors and Polish Pediatric Soft-tissue Sarcomas Studies between 1992 and 2002 are reported. RESULTS: Seven patients (F/M: 5/2, age 2-10 months) had infantile HPC, four of whom had primary tumors affecting superficial tissues of the trunk and upper limbs. No child had initial nodal or organ metastases. Primary excision (PE) was performed only in three patients with superficial lesions. They received no supplemental treatment. The remaining four children responded well to chemotherapy (CHT), entering complete remission after CHT alone (n= 2) or after delayed resection (n= 2). No relapses occurred and all patients were alive 48-146 months after treatment. Seven patients (F/M: 2/5, age 3.2-16.5 years) had adult-type HPC, five of whom had tumors localized in superficial tissues of the lower limbs or head/neck. All patients presented with locally advanced disease. PE was performed in five children (complete in four); all patients were alive at follow up of 40-127 months. Three patients died of recurrence after incomplete PE despite supplemental chemo- and radiotherapy. CONCLUSIONS: Complete surgical excision remains the mainstay of treatment for both HPC types. In unresectable adult-type HPC adjuvant chemo- and radiotherapy should be administered in macro- and microscopic tumor residues, but the prognosis is poor despite supplemental treatment. High chemo-responsiveness of infantile-type HPC produces a favorable outcome even in cases of unresectable, life-threatening tumors.

[Thymoma and thymic carcinoma--review of literature and clinical characteristics based on the Polish Paediatric Solid Tumours Study Group experience]. / Grasiczaki i raki grasicy--przeglad pismiennictwa i charakterystyka kliniczna w oparciu o dane Polskiej Pediatrycznej Grupy Guzów Litych.

Thymomas and thymic carcinomas are rare neoplasms derived from the epithelial tissue of thymus, very infrequently developing in young adults and children. The estimation of thymomas' invasiveness has been the matter of discussion for many years reflected by numerous clinical and histological classifications. In 1999 the WHO classification was created, joining all the most important issues present in previously used systems. It is believed that histological structure is the most important prognostic factor in thymic carcinomas while in less aggressive types of thymomas the clinical stages influence the outcome. Staging of thymomas is most commonly based on the Masoka classification. Independent evaluation of the stage and histological aggressiveness are necessary to predict the clinical course and outcome in thymomas. Thus the term 'malignant thymoma' has been replaced by 'invasive thymoma' in clinical practice. The treatment strategy depends on the clinical stages of thymoma. Complete resection of the tumour is the treatment of choice with supplementing radiotherapy in more advanced clinical stages. Chemotherapy in invasive thymomas has been reported to play an increasingly important role as induction, supplementing and palliative therapy. It has been proved that combined treatment improves the outcome in invasive thymomas, especially in thymic carcinomas. This paper reviews the literature data concerning the histology, clinical issues and treatment of thymomas and thymic carcinomas. The clinical data on nine children with thymic carcinomas treated between 1992 and 2006 in the Polish oncological and surgical centres were also analysed and presented. Based on multicentre data we were able to conclude the following: 1. Thymic carcinomas in children are very rare and that is why early diagnosis is often difficult. 2. At diagnosis most cases are already inoperable, which results in poorer prognosis. 3. Complex adjuvant chemo- and radiotherapy in childhood thymic carcinomas seem to prolong overall survival. 4. Further detailed analysis in all the cases of thymic carcinomas in children is recommended in order to estimate the optimal strategy of treatment.

[Analysis of microvascular density and the expression of vascular-endothelial growth factor (VEGF) and its membrane receptor Flk-1 in neuroblastoma]. / Analiza gestosci naczyniowej oraz ekspresji sródblonowo-naczyniowego czynnika wzrostu (VEFG) i jego receptora blonowego (FLK-1) w neuroblastoma.

AIM: To assess selected angiogenic markers; microvascular density and the expression of VEGF and Flk-1 in relation to clinical features and morphologic types of neuroblastoma. PATIENTS AND METHODS: Eighty-two children with neuroblastoma were studied. Morphological assessment was performed in paraffin embedded tissues of the primary tumours. Microvessels within tumour tissue were counted on immunohistochemically stained sections using anti CD34 antibody. The expression of VEGF and Flk-1 was estimated semiquantitively in immunohistochemically stained sections with adequate antibodies. The results of angiogenic studies were referred to the clinical data: age, clinical stage, localization and site of the primary tumour, serum LDH and ferritin at diagnosis. The correlation between angiogenic markers and morphological type of neuroblastoma was also evaluated. RESULTS: Microvascular density varies in a wide range (32-325/mm(2)). There was no significant statistical difference between previously untreated and tumours assessed after chemotherapy. Analyzing the correlations between the angiogenic markers and clinical features we found a converse relation between the age and microvascular density. The highest expression of VEGF was found in adrenal tumours in comparison to other localizations. Undifferentiated and poorly differentiated tumours presented a higher expression of VEGF and higher vascular density. Non significant higher expression of VEGF and higher vascular density was noticed in smaller <5 cm tumours. CONCLUSIONS: Correlations were found between the microvascular density and the age, diameter and the localisation of the primary tumour. Expression of VEGF depends on the localisation of the tumour. Neuroblastoma tumours arising in small children and poorly differentiated types of neuroblastoma indicate higher angiogenic activity.

[Renal neoplasms in children]. / Nowotwory nerek u dzieci.

UNLABELLED: Nephroblastoma is the most common kidney tumor in Polish children. OBJECTIVE: to present clinical material and outcome of 533 children with renal tumors. MATERIAL: 500 pts with nephroblastoma and 33 of non-Wilms: CMN, RCC,CSSK, RTK and others tumors were registered, mean age 4.5 years between 1993 till 2002. Stage: CS I--148, CS II--191, CS III--114, CS IV--51, CS V--29 pts. All pts with nephroblastoma were treated according to the first national PPGGL 01-92 protocol with pre-operative chemotherapy (ACT, VCR) for CS I-III and ACT, VCR, DOX in pts of stage IV, over the age of 6 months. Pre-operative chemotherapy was done to 93.8% pts. RESULTS: Radical nephrectomy post pre op chemotherapy was performed in 451 (98%) pts over 6 months and in 44 (8.2%) infants less than 6 months with nephroblastoma. Partial nephrectomy for unilateral tumor post preoperative chemotherapy was made in 6 (1.2%). In 26/29 (89.65%) of CS V nephroblastoma kidney sparing surgery was possible, and in 12 uni-lateral nephrectomy was performed. Surgical complications were mild and occurred only in 8.9% pts. RESULTS: 5-years overall survival of CS I pts (favorable and standard histology) is 93.48%, CS II--96.8%, CS III--84.4%, CS IV--67%, CS V--58%. The results of treatment of 33 pts with non-Wilms renal tumors have improved lately. 78.7% of our pts achieved 5-years overall survival. CONCLUSIONS: The use of systemic neoadjuvant chemotherapy in all pts over 6 months according to the recommendation of SIOP Nephroblastoma protocol (01-92) produced tumor shrinkage, facilitated complete surgical nephrectomy, and was very advantageous in the treatment of renal tumors in children. The results of treatment of non-Wilms tumor have also improved thanks to introduction of new and more aggressive regimens of chemotherapy.

[Rare tumours--are they really rare in the Polish children population?]. / Nowotwory rzadkie--czy rzeczywiscie rzadkie w populacji polskich dzieci?

Clear statement that pediatric neoplasms are really rare is not easy. Thus the incidence of rare tumours in children has not been defined so far. The paper efforts to assess the topic of rare tumours of childhood in the Polish population. Following two categories are proposed: tumours typical for adults, but possible in children (neoplasms of epithelial origin--mainly carcinomas, melanomas, carcinoids) and paediatric tumours consisting less than 10% of cases in corresponding clinical groups according to the ICCC classification. Data on 317 patients aged 0-18 years treated in centres associated in the Polish Paediatric Group for Solid Tumours (PPGST) were analysed. Classical adult malignancies were registered in 130 patients: carcinomas in 90 (mean age 12.6 +/- 4.5 years), melanomas in 25 (mean age 9.4 +/- 4.9) and carcinoids in 9 (mean age 14.5 +/- 1.2 years). Non epithelial neoplasms were registered in 187 patients (mean age 10.4 +/- 5.5). That group included rare tumours of soft tissue, CNS, bones and other organs. Treatments of certain groups were specified by separate therapeutic protocols within PPGST. Rare malignancies of adult-type among children under 18 years of age in Poland comprised 1.5% of all pediatric neoplasms. The incidence of adult-type neoplasms increased with age until 14 years. In patients over 15 years of age the number of registered cases decreased. It may suggest a first peak of incidence in early adolescence or an underestimation of number of patients with carcinoma aged over 15 years. In the analyzed group, the mean age of patients with carcinomas and other epithelial and unspecified tumours significantly exceeded the age of children with rare neoplasms of non-epithelial origin (12.1 +/- 4.7 vs 10.4 +/- 5.5 years; p<0.05). A very young age at diagnosis of malignant melanomas (mean 9.4 years) and numerous cases of carcinomas affecting the digestive tract (n=24; 27% of all carcinomas), especially those located in colorectal region (n=10), seem surprising. The preliminary analysis of the collected data on rare neoplasms in Poland encourage to undertake a prospective study, meant to link the epidemiology and characteristics of rare epithelial tumours in childhood with diagnostic and therapeutic suggestions for these types that are not coordinated within Polish Paediatric Group of Solid Tumours.

[Malignant vascular tumours in children -- report from the Polish Pediatric Rare Tumors Study]. / Charakterystyka kliniczna naczyniopochodnych nowotworów zlosliwych u dzieci -- raport Programu Guzów Rzadkich PPGGL.

UNLABELLED: Malignant vascular tumours represent a rare group of neoplasms, usually treated according to protocols for soft tissue sarcomas. THE AIM OF THE STUDY: To assess the clinical characteristics, disease course and outcome in Polish children with malignant vascular neoplasms. MATERIAL AND METHODS: The Polish Paediatric Rare Tumours Study retrospectively analysed multicentre data on 32 children with vascular tumours, registered between 1992 and 2002. On the basis of the histological type of the neoplasm these patients have been divided into three groups: group I -- 10 patients with angiosarcoma (ASA), group II -- 7 children with haemangioendothelioma (HE) and group III- 15 patients with haemangiopericytoma (HP), of both infantile (7 children) and adult-types (8 patients). RESULTS: Group I: 5 patients presented with local, 3 with systemic and 2 with regional disease. Primary complete resection (PRC) was performed in 7 patients, not resulting in local control in any of them. Radiotherapy (RTX) was administered in 5 patients, chemotherapy (CHT) in all. 7 patients relapsed, 3 never entered clinical remission. 9 of the 10 patients of group I, died of disease progression. Group II: PRC was performed in 5 patients and led to local control in 2. Adjuvant RTX was used in 2 and CHT in 4 patients. 2 children relapsed and died of the disease. Infantile HP: PRC was performed in 3 children, remaining 4 patients received adjuvant CHT All children entered complete remission and are disease-free. Adult-type HP: PRC was performed in 5 patients, resulting in local control in 4. Five children were given adjuvant RTX and six CHT Three patients relapsed and died of disease progression. CONCLUSIONS: The effectiveness of primary complete resection in all groups was doubtful. The high rate of metastatic relapses suggests that the currently given systemic therapy is not satisfactory. The only tumour with excellent prognosis was infantile type HP (all patients are alive and free of disease). Adequate treatment for children with angiosarcoma remains still unknown -- 9 of 10 patients died of disease progression. Prognosis in patients with haemangioendothelioma is intermediate, however the role of immunotherapy should be further investigated.

[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.