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The previous International Society of Paediatric Oncology (SIOP) trials and studies recognized three prognostic groups of renal tumors of childhood: low risk, intermediate risk, and high risk tumors, which were further defined in the SIOP (Stockholm) Working Classification of Renal Tumors of Childhood (1994). The results of the latest SIOP Trials and Studies showed that certain histological features which remain after preoperative chemotherapy, such as blastema, are of prognostic significance while others are not. Therefore, in the next SIOP Trials and Study a revised classification of renal tumors will be followed. It still recognizes the three tumor risk groups with different types in each of them, but for treatment purposes, only three major types of nephroblastoma need to be recognized: completely necrotic (low risk tumor), blastemal (high risk tumor), and others (intermediate risk tumors). Patients will be treated according to tumor histology and stage. Trials which include preoperative chemotherapy have shown that the presence of necrotic tumor or chemotherapy induced changes in the renal sinus or perirenal fat can be ignored for distinguishing between stage I and II, but if present at resection margins or lymph nodes, it should be regarded as stage III. Prognostic significance of all histological component of Wilms tumors will be studied prospectively in the new trial., (Copyright 2002 Wiley-Liss, Inc.)

Background: In Langerhans cell histiocytosis (LCH) pulmonary involvement, which is often initially asymptomatic, may contribute to significant morbidity and mortality. To determine the long-term prognosis, a cross-sectional study was undertaken., Procedure: Forty-one patients with > or = 5 years follow-up after the diagnosis of LCH were interviewed and underwent physical examination, blood tests, a chest X-ray and a high-resolution CT (HRCT) of the lungs. All patients included had been referred to the Department of Pediatrics at the Karolinska Hospital in Stockholm between July 1962 and February 1990 (median follow-up 16 years). Biopsies from all patients were reviewed and confirmed to be consistent with LCH. Information on previous clinical features including treatment and the results of chest X-rays were also collected for risk factor analysis., Results: Radiographic abnormalities of the lungs (cysts and/or emphysema), found in 10/41 (24%) at follow-up, were classified into five groups according to the extent of the cysts. These patients had more often suffered from multisystem than from single-system disease (P = 0.01), were significantly older at diagnosis (P < 0.001), and had been more heavily treated with chemotherapy and/or radiotherapy. They were also more frequently smokers (P < 0.0001) and 7/10 (70%) had suffered lung involvement at diagnosis. At the time of diagnosis of the pulmonary involvement, 4/10 (40%) patients had respiratory symptoms, but only 2/10 (20%) had symptoms at follow-up., Conclusions: Ten (24%) of the 41 patients had abnormal findings on radiological examination of the lungs at long-term follow-up and seven are or had been smokers. It is of great importance that patients with LCH be informed about smoking-related pulmonary morbidity. Prolonged monitoring of the lungs for smokers and patients with known pulmonary involvement is recommended., (Copyright 2001 Wiley-Liss, Inc.)

With the aid of IGF2 and VEGF in situ hybridization; tyrosine hydroxylase, chromogranin A, and Ki67 immunohistochemistry; and TUNEL staining applied to a large series of clinical neuroblastomas and to an animal model, we show here that stroma-poor neuroblastomas show evidence of chromaffin differentiation similar to that of type 1 small intensely fluorescent (SIF) cells and that this occurs in a vascular-dependent fashion, indicating a role for local tumor hypoxia in the differentiation process.

Background: The SIOP Nephroblastoma therapeutic protocols include a period of preoperative chemotherapy followed by nephrectomy and a period of postoperative chemotherapy. From the outset, identification of low-risk groups has been an aim of the SIOP Nephroblastoma Trials and Studies. Now that 90% of children with Wilms tumor can be cured, attention is even more focused on the identification of patients who could benefit from less aggressive postoperative therapy, thus minimizing the morbidity and late effects associated with treatment. The prognostic implications of total necrosis in nephroblastoma after chemotherapy have not been investigated hitherto., Procedure: Between November 1, 1987 and June 30, 1993, 599 patients referred to the SIOP-9 Nephroblastoma Trial and Study were preoperatively treated and classified as stages I-IV nonanaplastic Wilms tumor., Results: Of these 599 patients, pathologic examination of the nephrectomy specimen revealed a completely necrotic Wilms tumor (CNWT) with no viable tumor remaining in 59 (10%): these comprised 37 stages I-III and 22 stage IV. Of these patients, 58 (98%) had no evidence of disease at 5 years vs. 90% for the rest of the cohort (P < 0.05). Stages I-III patients represented 63% of CNWT and had a 97% overall survival rate. The only death was related to veno-occlusive disease and occurred in a stage I patient in the month following nephrectomy. Stage IV patients represented 37% of CNWT (vs. only 10% of all other cases of unilateral nonanaplastic Wilms tumor) and had a 100% rate of survival. Children with CNWT were older (mean 59 months vs. 43 months); their tumor at diagnosis was larger and had regressed more significantly at subsequent ultrasound examination. The data also uphold the hypothesis that Wilms tumors of blastemic pattern are most aggressive, but also are extremely responsive to chemotherapy., Conclusions: Patients with unilateral nonanaplastic WT that showed total necrosis following preoperative chemotherapy had excellent outcome and should benefit from less aggressive postoperative treatment in further trials. Other very responsive tumors, such as Wilms with <10% viable tumor, should also be assessed.

Background: Unlike the original definitions of focal (FA) and diffuse anaplasia (DA) in Wilms tumor (WT), recently redefined FA and DA proved to be of prognostic significance. The aim of the study was to analyze WT from the SIOP file, the majority of which were treated with preoperative chemotherapy, in order to investigate whether chemotherapy influenced the presence of anaplasia, whether the new definitions were applicable to these tumors, and whether they were of prognostic significance., Procedure: The unilateral anaplastic WT of children up to 16 years of age from the SIOP 6 and 9 nephroblastoma trials and studies were first classified according to the original definitions and analyzed. Then they were reclassified and analyzed according to the new definitions., Results: Anaplasia was diagnosed in 86 (5.5%) of 1,554 unilateral WT. The age at diagnosis ranged from 9 to 175 months (median, 63) and more than half of children were over 5 years of age. From 15% to 85% of the tumor mass showed chemotherapy-induced changes. Blastemal anaplasia was seen in 74, stromal in 23, and epithelial in 22 cases. According to the original definitions, FA was diagnosed in 55 (64%) and DA in 31 (36%) cases. In total, 48% children were alive and well, including 53% with FA and 39% with DA (P = 0.23). When reclassified, 39 old FA cases were moved to the new DA group, resulting in 70 (81%) DA and 16 (19%) FA cases. The female-to-male ratio for FA changed from 1.9:1 to 1:1 while remained unchanged for DA. The percentage of FA stage I cases increased from 31% to 44%, while it decreased from 25% to 6% for stage III. For other stages it remained virtually unchanged. The overall 4-year actual survival was 75% for FA and 41% for DA (P = 0.03)., Conclusions: Preoperative chemotherapy did not obliterate or produce anaplasia. The new definitions were applicable to pretreated cases and they were of prognostic significance.

Background: The current International Society of Paediatric Oncology (SIOP)-10 protocol does not allow pretreatment histological classification of low-stage renal tumors in children for fear of needle tract recurrences. The aims of this retrospective study were to evaluate the safety, sensitivity, and specificity of ultrasound-guided cutting needle biopsies (UCNB) performed at our institution in pediatric patients with renal tumors., Procedure: Of 28 pediatric patients presenting with a renal tumor between 1988 and 1996, 25 underwent biopsy with the Biopty biopsy instrument (needle diameter 1.2 mm). The preoperative biopsy and nephrectomy slides were reviewed by a SIOP reference pathologist. The patients' hospital records were reviewed and biopsy complications were noted., Results: At review of the nephrectomy slides, the diagnoses were: Wilms tumor (16 patients), with anaplasia in one case, rhabdoid tumor (2 patients), neuroblastoma (2 patients), mesoblastic nephroma (2 patients), clear cell sarcoma (1 patient), malignant teratoma (1 patient), and renal cell carcinoma (1 patient). No needle tract recurrence or other major complication was observed. The only complication was local pain at the biopsy site, which occurred in 24% (6/25) of the cases. The sensitivity of UCNB was 76% (19/25); five biopsies did not yield diagnostic material and one was not concordant. All cases of Wilms tumor were correctly diagnosed by UCNB, but only 33% (3/9) of the other tumors., Conclusions: In all cases of Wilms tumor a correct diagnosis was made. The overall sensitivity was 76%. UCNB proved to be a safe procedure that was not associated with needle tract recurrence or other serious complications.