Pulmonary metastases at diagnosis of neuroblastoma in pediatric patients: CT findings and prognosis

The role of surgery in the treatment of neuroblastoma metastases at rare sites

PURPOSE

Treatment of neuroblastoma metastases usually consists of chemotherapy and irradiation. However, in selected cases, surgical treatment is also indicated. In this study, we present three cases of patients with neuroblastoma metastases at rare sites that underwent surgery.

MATERIALS AND METHODS

We retrospectively analyzed data of patients who underwent surgery for neuroblastoma at our department of Pediatric Surgery and Pediatric Urology at the University Children's Hospital in Tuebingen and selected those patients who had surgery explicitly for a metastasis.

RESULTS

Between 2002 and 2020, 277 children underwent surgical treatment for neuroblastoma. Three cases with metastases at exceptional sites are presented here after therapy according to protocols. One patient had a penile metastasis and received surgery including a plastic reconstruction. The patient showed no signs of erectile or urinary dysfunction at follow-up. Another patient had a metastasis in the proximal ulna, which remained vital even after exhausted treatment after two relapses. Afterward there was no restriction of movement of the extremity. The third patient had, amongst others, metastases to the pancreatic body and to the liver. Both were surgically removed during primary tumor resection. This patient died after local tumor relapse. The other two patients showed no evidence of tumor relapse after a follow-up of 18 and 17 months, respectively.

CONCLUSION

Although children with neuroblastoma often present with metastases, there is no recommendation for surgical treatment other than diagnostic biopsies. In case of persistence of metastasis or after exhaustion of high-risk therapy, surgical resection must be considered.

Different tumorigenicity and distinct metastasis and gene signature between orthotopic and subcutaneous neuroblastoma xenografted mice

Patient-derived (PDX) and cell-derived (CDX) xenograft models are widely used in preclinical studies of human neuroblastoma. In this study, we constructed orthotopic and subcutaneous neuroblastoma CDX models by injecting human neuroblastoma cells into the adrenal gland and the flanks of immunodeficient mice, respectively. The tumorigenesis, metastasis and response to chemotherapy for the two models were also compared. Our results indicated that orthotopic tumor mice showed significantly faster tumor growth than that of subcutaneous mice. Importantly, the expression of PHOX2B and GAB2 was dramatically increased in the tumors of orthotopic CDX mice. Furthermore, orthotopic CDX mice developed multiple organ metastasis resembling that of neuroblastoma patients, while metastasis occurred predominantly in lung in subcutaneous CDX mice. Moreover, the two CDX models showed comparable response to cyclophosphamide treatment. Our results suggest that orthotopic CDX mice are superior to subcutaneous CDX mice as a preclinical model to study human neuroblastoma.

PET/CT Normal Variants and Pitfalls in Pediatric disorders

18F- Fluoro-deoxyglucose positron emission computed tomography (18F-FDG PET CT) is an established modality used mainly in oncology. Though it has widespread oncologic indications, it is not tumor specific. Apart from the physiological distribution, uptake of FDG may be seen in many benign conditions, including infection and inflammation in children and adults. Performing and acquiring a technically adequate PET CT study may be more challenging in children. Proper preparation and an acceptable imaging protocol will help to avoid re-acquisition and in minimizing the radiation exposure. Sound knowledge of the physiological variants and benign conditions that are specific to the pediatric population will aid in correct interpretation of the PET CT study. It is important that radiologists and Nuclear Medicine physicians who report these studies are well-acquainted with these pitfalls to avoid false positive studies.

Venous Tumor Thrombosis and Pulmonary Metastases in a Case of Adrenal Neuroblastoma—Occurrence of Two Rare Manifestations in a Single Patient: Case Report and Review of Literature

Unlike other pediatric extra cranial solid neoplasms, neuroblastomas have very low incidence of pulmonary metastases. Neuroblastomas also tend to encase rather than infiltrate the major vessels with very low incidence of tumor thrombus. Even in cases with inferior vena cava tumor thrombosis, pulmonary metastases are a rare occurrence. These patients usually show widespread disseminated disease at presentation. We present a rare case of adrenal neuroblastoma with tumor thrombus and bilateral pulmonary metastases at presentation. This presentation can be confused with adrenocortical carcinoma and differentiating between the two is essential for further management.

Pulmonary Metastasectomy in Pediatric Solid Tumors

Metastatic disease and the complications of treating metastatic disease are the primary causes of mortality in children with solid malignancies. Nearly 25% of children with solid tumors have metastatic disease at initial diagnosis and another 20% develop metastases during or after treatment. The most common location of these metastases is the lung. The role of surgery in metastatic disease depends greatly on the histology of the primary. In general, tumors that are refractory to adjuvant therapies are most appropriate for pulmonary metastasectomy. This article will summarize the indications for metastasectomy in pediatric solid tumors and discuss the ongoing debate over the technique of metastasectomy in osteosarcoma.

Clinical and biological features of neuroblastic tumors: A comparison of neuroblastoma and ganglioneuroblastoma

Neuroblastoma (NB), ganglioneuroblastoma intermixed (GNBi) and ganglioneuroblastoma nodular (GNBn) are neuroblastic tumors that present with a wide range of symptoms and variable prognoses. We retrospectively reviewed the pretreatment clinical (age, sex and tumor stage) and biological (MYCN amplification; and levels of lactate dehydrogenase, ferritin and neuron-specific enolase) characteristics of 279 patients who were diagnosed with pathologically confirmed NB and GNB from January 2005 to December 2015. The median age at diagnosis increased with grade of differentiation (NB: 28.9 months; GNBn: 38.4 months; GNBi: 47.5 months; p < 0.01). NB patients were more frequently diagnosed with adrenal tumors and had a higher prevalence of abnormal serum ferritin at the time of diagnosis (60.0% vs. 40.0% vs. 12.0%, P<0.001), NSE (96.0% vs. 93.0% vs. 81.0%, P=0.013) when compared with GNBn and GNBi patients. The prevalence rates of disseminated tumors and MYCN amplified tumors were lower in the GNBi group than in the GNBn and NB groups (13.0% vs. 25.0% vs. 44.0%, P=0.002; 0 vs. 14.0% vs. 26.0%, P=0.032, respectively). The overall survival (OS) of patients with GNB was significantly better than that of patients with NB (GNBi: 100%, GNBn: 74.5±11.4%, NB: 50.8±4.5%, respectively; P<0.01). Our study revealed that both NB and GNB have a wide range of presentations, and clinicians should be aware of both typical and atypical symptoms and signs. Children with GNB (especially GNBi) were more likely to present favorable prognostic factors than their NB counterparts, which consequently lead to better outcomes and longer survival for these patients.

Metastasectomy in pediatric patients: indications, technical tips and outcomes

Pulmonary metastasectomy has become a standard procedure for pediatric patients with certain types of solid tumors. Surgeons, expert pediatric oncologists and radiation oncologists contribute with their different skills to the management of pulmonary metastases. Patients are usually scheduled for surgery in case of primary tumor control, in absence of metastases in other organs and when a complete resection is achievable. Nodules are removed through precision resections using electrocautery or laser methods in order to ensure radical surgery with adequate margins. With these techniques, it is possible to preserve the surrounding parenchyma and cause a limited volumetric distortion as compared with staplers. Anatomical resections (segmentectomy, lobectomy or pneumonectomy) should be reserved for selected cases, since major lung resection can only be justified if it leads to a real oncological advantage. Repeated thoracotomies are possible, since there is no theoretical limit to reinterventions. Surgery of lung metastases has a therapeutic and curative role for some histology with acceptable rate of complications but it finds its role only in an aggressive multimodality approach. Indications can be discussed case by case and exceptions can be evaluated also in presence of different evidences. Children affected by metastatic tumors need to be managed by expert multidisciplinary oncological team in referral center with large experience.

Prominent Pulmonary Metastases Without Concurrent Osseous Involvement in Patients With High-Risk Neuroblastoma

Metastases from high-risk neuroblastomas generally are to the bone or bone marrow. Multiple lung metastases are rare, especially when there was no concurrent osseous metastasis. We report 2 cases of high-risk neuroblastomas having prominent lung metastases without concurrent osseous lesion observed.

PHOX2B is a suppressor of neuroblastoma metastasis

Paired like homeobox 2B (PHOX2B) is a minimal residual disease (MRD) marker of neuroblastoma. The presence of MRD, also referred to as micro-metastases, is a powerful marker of poor prognosis in neuroblastoma.

Lung metastasis is considered a terminal event in neuroblastoma. Lung micro-metastatic neuroblastoma (MicroNB) cells show high expression levels of PHOX2B and possess a less malignant and metastatic phenotype than lung macro metastatic neuroblastoma (MacroNB) cells, which hardly express PHOX2B.

In vitro assays showed that PHOX2B knockdown in MicroNB cells did not affect cell viability; however it decreased the migratory capacity of the MicroNB-shPHOX2B cells. An orthotopic inoculation of MicroNB-shPHOX2B cells into the adrenal gland of nude mice resulted in significantly larger primary tumors and a heavier micro-metastatic load in the lungs and bone-marrow, than when control cells were inoculated.

PHOX2B expression was found to be regulated by methylation. The PHOX2B promoter in MacroNB cells is significantly more methylated than in MicroNB cells. Demethylation assays using 5-azacytidine demonstrated that methylation can indeed inhibit PHOX2B transcription in MacroNB cells.

These pre-clinical data strongly suggest that PHOX2B functions as a suppressor of neuroblastoma progression.

The Beta Subunit of Hemoglobin (HBB2/HBB) Suppresses Neuroblastoma Growth and Metastasis

Soluble pulmonary factors have been reported to be capable of inhibiting the viability of cancer cells that metastasize to the lung, but the molecular identity was obscure. Here we report the isolation and characterization of the beta subunit of hemoglobin as a lung-derived antimetastatic factor. Peptide mapping in the beta subunit of human hemoglobin (HBB) defined a short C-terminal region (termed Metox) as responsible for activity. In tissue culture, both HBB and murine HBB2 mediated growth arrest and apoptosis of lung-metastasizing neuroblastoma cells, along with a variety of other human cancer cell lines. Metox acted similarly and its administration in human tumor xenograft models limited the development of adrenal neuroblastoma tumors as well as spontaneous lung and bone marrow metastases. Expression studies in mice indicated that HBB2 is produced by alveolar epithelial and endothelial cells and is upregulated in mice bearing undetectable metastasis. Our work suggested a novel function for HBB as a theranostic molecule: an innate antimetastasis factor with potential utility as an anticancer drug and a biomarker signaling the presence of clinically undetectable metastasis. Cancer Res; 77(1); 14-26. ©2016 AACR.

Surgical treatment of pulmonary metastases in pediatric solid tumors

Most children who succumb to solid malignancies do so because of the burden of metastatic disease or due to complications associated with the therapy administered to treat metastatic disease. Approximately one-quarter of children with solid tumors will present with metastatic disease, and an additional 20% ultimately develop metastatic disease, most commonly in the lung. The role of surgery in the treatment of metastatic solid tumors, given its disseminated nature, is not intuitive, yet there are circumstances in which surgical resection of metastatic disease can potentially be curative. However, the utility of surgery is very much dependent on histology, and generally is most appropriate for those malignancies with histologies that are refractory to other adjuvant therapies.

Primary renal neuroblastoma with metastasis and matrix metalloproteinase-14 expression

We herein report the rare case of a 4-year-5-month-old boy who presented with primary renal neuroblastoma. The patient developed repeated lung and liver metastatic recurrences, but, following a combination of chemotherapy, radiation therapy and aggressive surgical resection, the patient is now in remission. To investigate the pathogenesis of lung metastasis, immunohistochemistry was performed for matrix metalloproteinase-9 and -14 (MMP-9 and MMP-14), molecular markers of invasion, metastasis and angiogenesis in neuroblastoma. In the present case, MMP-9 expression was not observed, but MMP-14 expression was detected in the primary lesion and was more highly expressed in the metastatic lesion compared with the primary one. Given the MMP-14 staining in other cases, expression of MMP-14 may be associated with the aggressiveness of the tumor. This suggests that selected clones with high MMP-14 expression in the primary tumor might metastasize and form MMP-14-rich lesions.

The role of chest computed tomography (CT) as a surveillance tool in children with high-risk neuroblastoma

BACKGROUND

Standardization of imaging obtained in children with neuroblastoma is not well established. This study examines chest CT in pediatric patients with high-risk neuroblastoma.

PROCEDURE

Medical records and imaging from 88 patients with high-risk neuroblastoma, diagnosed at St. Jude Children's Research Hospital between January, 2002 and December, 2009, were reviewed. Surveillance imaging was conducted through 2013. Ten patients with thoracic disease at diagnosis were excluded. Event free survival (EFS) and overall survival (OS) were estimated. Size specific dose estimates for CT scans of the chest, abdomen, and pelvis were used to estimate absolute organ doses to 23 organs. Organ dosimetry was used to calculate cohort effective dose.

RESULTS

The 5 year OS and EFS were 51.9% ± 6.5% and 42.6% ± 6.5%, respectively. Forty-six (58.9%) patients progressed/recurred and 41 (52.6%) died of disease. Eleven patients (14%) developed thoracic disease progression/recurrence identified by chest CT (1 paraspinal mass, 1 pulmonary nodules, and 9 nodal). MIBG (metaiodobenzylguanidine) scans identified thoracic disease in six patients. Five of the 11 had normal chest MIBG scans; three were symptomatic and two were asymptomatic with normal chest MIBG scans but avid bone disease. The estimated radiation dose savings from surveillance without CT chest imaging was 42%, 34% when accounting for modern CT acquisition (2011-2013).

CONCLUSIONS

Neuroblastoma progression/recurrence in the chest is rare and often presents with symptoms or is identified using standard non-CT imaging modalities. For patients with non-thoracic high-risk neuroblastoma at diagnosis, omission of surveillance chest CT imaging can save 35-42% of the radiation burden without compromising disease detection.

The CXCR4/CXCR7/CXCL12 Axis Is Involved in a Secondary but Complex Control of Neuroblastoma Metastatic Cell Homing

Neuroblastoma (NB) is one of the most deadly solid tumors of the young child, for which new efficient and targeted therapies are strongly needed. The CXCR4/CXCR7/CXCL12 chemokine axis has been involved in the progression and organ-specific dissemination of various cancers. In NB, CXCR4 expression was shown to be associated to highly aggressive undifferentiated tumors, while CXCR7 expression was detected in more differentiated and mature neuroblastic tumors. As investigated in vivo, using an orthotopic model of tumor cell implantation of chemokine receptor-overexpressing NB cells (IGR-NB8), the CXCR4/CXCR7/CXCL12 axis was shown to regulate NB primary and secondary growth, although without any apparent influence on organ selective metastasis. In the present study, we addressed the selective role of CXCR4 and CXCR7 receptors in the homing phase of metastatic dissemination using an intravenous model of tumor cell implantation. Tail vein injection into NOD-scid-gamma mice of transduced IGR-NB8 cells overexpressing CXCR4, CXCR7, or both receptors revealed that all transduced cell variants preferentially invaded the adrenal gland and typical NB metastatic target organs, such as the liver and the bone marrow. However, CXCR4 expression favored NB cell dissemination to the liver and the lungs, while CXCR7 was able to strongly promote NB cell homing to the adrenal gland and the liver. Finally, coexpression of CXCR4 and CXCR7 receptors significantly and selectively increased NB dissemination toward the bone marrow. In conclusion, CXCR4 and CXCR7 receptors may be involved in a complex and organ-dependent control of NB growth and selective homing, making these receptors and their inhibitors potential new therapeutic targets.

The metastatic microenvironment: lung-derived factors control the viability of neuroblastoma lung metastasis

Recent data suggest that the mechanisms determining whether a tumor cell reaching a secondary organ will enter a dormant state, progress toward metastasis, or go through apoptosis are regulated by the microenvironment of the distant organ. In neuroblastoma, 60-70% of children with high-risk disease will ultimately experience relapse due to the presence of micrometastases. The main goal of this study is to evaluate the role of the lung microenvironment in determining the fate of neuroblastoma lung metastases and micrometastases. Utilizing an orthotopic mouse model for human neuroblastoma metastasis, we were able to generate two neuroblastoma cell populations-lung micrometastatic (MicroNB) cells and lung macrometastatic (MacroNB) cells. These two types of cells share the same genetic background, invade the same distant organ, but differ in their ability to create metastasis in the lungs. We hypothesize that factors present in the lung microenvironment inhibit the propagation of MicroNB cells preventing them from forming overt lung metastasis. This study indeed shows that lung-derived factors significantly reduce the viability of MicroNB cells by up regulating the expression of pro-apoptotic genes, inducing cell cycle arrest and decreasing ERK and FAK phosphorylation. Lung-derived factors affected various additional progression-linked cellular characteristics of neuroblastoma cells, such as the expression of stem-cell markers, morphology, and migratory capacity. An insight into the microenvironmental effects governing neuroblastoma recurrence and progression would be of pivotal importance as they could have a therapeutic potential for the treatment of neuroblastoma residual disease.

Pediatric primary and metastatic neuroblastoma: MRI findings: pictorial review

Magnetic resonance imaging (MRI) has become one of the most valuable modalities for initial and follow-up imaging of suspected or known neuroblastoma (NBL) owing to its excellent inherent contrast, lack of ionizing radiation and multiplanar imaging capability. Importantly, NBL has a variable appearance on different imaging modalities, and this is particularly pertinent to MRI. MRI is a cornerstone for management of NBL, providing essential information at initial presentation regarding diagnosis, staging, resectability and relation to vital structures. It can also define the extent of residual disease after surgical resection or assess the efficacy of treatment. Follow-up MRI is frequently performed to ensure sustained complete remission or to monitor known residual disease. This pictorial review article aims to provide the reader with a concise, yet comprehensive, collection of MR images of primary and metastatic NBL lesions with relevant correlation with other imaging modalities.

Giant non-functioning adrenocortical carcinoma: A rare childhood tumor

Adrenocortical carcinoma (ACC) is a rare malignancy, especially in children. The overall incidence is approximately 2 cases per million per year.[1] In children, the incidence is 0.3 cases per million per year, except in southern Brazil where the incidence is 3.4–4.2 cases per million per year.[2] We describe a giant nonfunctioning metastasized ACC in a 6-year-old girl who presented with a history of increasing abdominal girth incidentally noticed by her mother since 1 week. Ultrasound abdomen showed a large right suprarenal tumor with calcifications and necrosis. Empty left renal fossa and compensatory enlarged right kidney were seen. Computed tomography (CT) scan revealed a large heterogenously enhancing right suprarenal mass with calcification and necrosis with pulmonary metastasis. Histopathology report from the right suprarenal mass revealed an ACC. With a stage IV disease, the patient died after 2 months from diagnosis.

Guidelines for imaging and staging of neuroblastic tumors: consensus report from the International Neuroblastoma Risk Group Project

Neuroblastoma is an enigmatic disease entity; some tumors disappear spontaneously without any therapy, while others progress with a fatal outcome despite the implementation of maximal modern therapy. However, strong prognostic factors can accurately predict whether children have "good" or "bad" disease at diagnosis, and the clinical stage is currently the most significant and clinically relevant prognostic factor. Therefore, for an individual patient, proper staging is of paramount importance for risk assessment and selection of optimal treatment. In 2009, the International Neuroblastoma Risk Group (INRG) Project proposed a new staging system designed for tumor staging before any treatment, including surgery. Compared with the focus of the International Neuroblastoma Staging System, which is currently the most used, the focus has now shifted from surgicopathologic findings to imaging findings. The new INRG Staging System includes two stages of localized disease, which are dependent on whether image-defined risk factors (IDRFs) are or are not present. IDRFs are features detected with imaging at the time of diagnosis. The present consensus report was written by the INRG Imaging Committee to optimize imaging and staging and reduce interobserver variability. The rationales for using imaging methods (ultrasonography, magnetic resonance imaging, computed tomography, and scintigraphy), as well as technical guidelines, are described. Definitions of the terms recommended for assessing IDRFs are provided with examples. It is anticipated that the use of standardized nomenclature will contribute substantially to more uniform staging and thereby facilitate comparisons of clinical trials conducted in different parts of the world.

Lung-residing metastatic and dormant neuroblastoma cells

The mechanism by which dormant tumor cells can begin growing after long periods of inactivity and accelerate disease recurrence is poorly understood. The present study characterizes dormant neuroblastoma (NB) cells, as well as metastatic cells, which reside in the same organ microenvironment. A xenograft model of human NB consisting of variants that generate nonmetastatic local tumors in the orthotopic inoculation site and variants that generate lung metastatic NB (MetNB) cells was developed in our laboratory. The present study shows that lungs of mice inoculated with nonmetastatic NB variants contain disseminated neuroblastoma (DisNB) human cells. Both DisNB and MetNB variants expressed a similar tumorigenicty phenotype in vivo, whereas the MetNB variants produced a heavy metastatic load and the DisNB variants produced no or little metastasis. A comparative in vitro characterization of MetNB and DisNB cells revealed similarities and differences. DisNB, but not MetNB cells, expressed the minimal residual disease markers PHOX2B and TH. MetNB cells demonstrated higher migratory capacity, an elevated matrix metalloproteinase (MMP) secretion, and a higher constitutive phosphorylation of extracellular signal-regulated kinase (ERK) than DisNB cells. We suggest that characteristics common to both MetNB and DisNB cells were acquired relatively early in the metastatic process and the characteristics that differ between these variants were acquired later. We hypothesize that the DisNB cells are metastasis precursors, which may progress toward metastasis under certain microenvironmental conditions.

CT characteristics of lung nodules present at diagnosis of extrapulmonary malignancy in children

OBJECTIVE

The purpose of this study was to evaluate the CT characteristics of lung nodules present at diagnosis of extrapulmonary malignancies in children.

MATERIALS AND METHODS

We performed a retrospective analysis of CT images of children seen in our oncology service over a 6-year period. We included all children diagnosed with a non-CNS solid extrapulmonary malignancy or lymphoma who had also undergone chest CT at presentation. Images were reviewed for the presence of lung nodules; if present, the following nodular characteristics were recorded: sidedness, number, distribution, CT attenuation, shape, margins, calcification, and size. When available, pathology results were correlated with the nodules found on CT.

RESULTS

One hundred eleven infants and children (age range, 14 days-17 years 10 months; median age, 11 years 8 months) had lung nodules on CT. The nodules showed a variety of patterns, but the most common findings were bilateral lung nodules (71 of 111 patients), between two and 10 in number (60 patients), peripheral distribution (98 patients), < or = 5 mm (48 patients), oval shape (45 patients), solid attenuation (74 patients), smoothly marginated (91 patients), and noncalcified (107 patients). Twenty-seven patients underwent biopsy. Seventeen biopsies showed benign lesions and nine, malignant lesions; the results for the remaining biopsy were inconclusive. In the subgroup of lung nodules that underwent biopsy, none of the CT characteristics was able to differentiate benignity from malignancy.

CONCLUSION

Lung nodules in children with extrapulmonary malignancies showed a variety of patterns on CT. In the subgroup of lung nodules that underwent biopsy, none of the nodule features studied on CT reliably differentiated benignity from malignancy.

Gene-expression-based analysis of local and metastatic neuroblastoma variants reveals a set of genes associated with tumor progression in neuroblastoma patients

Metastasis is the primary cause of mortality in Neuroblastoma (NB) patients, but the metastatic process in NB is poorly understood. Metastsis is a multistep process that requires the coordinated action of many genes. The identification of genes that promote or suppress tumor metastasis can advance our understanding of this process. In the present study, we utilized a human NB xenograft model comprising local and metastatic NB variants, which was recently developed in our laboratory. We set out to identify molecular correlates of NB metastasis and to determine the clinical relevance of these molecules. We first performed genome-wide expression profiles of metastatic and nonmetastatic NB variants that have an identical genetic background. We found that some of the proteins highly expressed in the metastatic NB variants are localized in the cytoplasm and endoplasmic reticulum. Other proteins are linked to metabolic processes and signaling pathways, thereby supporting the invasive and metastatic state of the cells. Subsequently, we intersected the differentially expressed genes in the human xenografted variants with genes differentially expressed in Stage 1 and Stage 4 primary tumors of NB patients. By using the same gene-expression platform, molecular correlates associated with metastatic progression in primary NB tumors were identified. The resulting smaller gene set was clinically relevant as it discriminated between high- and low-risk NB patients.

The International Neuroblastoma Risk Group (INRG) staging system: an INRG Task Force report

PURPOSE

The International Neuroblastoma Risk Group (INRG) classification system was developed to establish a consensus approach for pretreatment risk stratification. Because the International Neuroblastoma Staging System (INSS) is a postsurgical staging system, a new clinical staging system was required for the INRG pretreatment risk classification system.

METHODS

To stage patients before any treatment, the INRG Task Force, consisting of neuroblastoma experts from Australia/New Zealand, China, Europe, Japan, and North America, developed a new INRG staging system (INRGSS) based on clinical criteria and image-defined risk factors (IDRFs). To investigate the impact of IDRFs on outcome, survival analyses were performed on 661 European patients with INSS stages 1, 2, or 3 disease for whom IDRFs were known.

RESULTS

In the INGRSS, locoregional tumors are staged L1 or L2 based on the absence or presence of one or more of 20 IDRFs, respectively. Metastatic tumors are defined as stage M, except for stage MS, in which metastases are confined to the skin, liver, and/or bone marrow in children younger than 18 months of age. Within the 661-patient cohort, IDRFs were present (ie, stage L2) in 21% of patients with stage 1, 45% of patients with stage 2, and 94% of patients with stage 3 disease. Patients with INRGSS stage L2 disease had significantly lower 5-year event-free survival than those with INRGSS stage L1 disease (78% +/- 4% v 90% +/- 3%; P = .0010).

CONCLUSION

Use of the new staging (INRGSS) and risk classification (INRG) of neuroblastoma will greatly facilitate the comparison of risk-based clinical trials conducted in different regions of the world.

Minimally invasive thoracoscopic ultrasound for localization of pulmonary nodules in children

PURPOSE

Children with cancer may develop lesions in the lung that may represent metastatic disease. Thoracotomy is considered the standard approach for resection of pulmonary nodules. Recently, thoracoscopic techniques have been applied in these situations. However, nodules that are deep in the lung parenchyma may not be visible. A technique has been developed whereby minimally invasive thoracoscopic ultrasound (MITUS) may be used to guide resection of deep pulmonary nodules.

METHODS

We conducted a retrospective review of children undergoing MITUS at our institution. Only patients with single isolated lesions were chosen to have this diagnostic procedure performed. Patients undergo single lung ventilation. Two 5-mm ports are inserted, one for the grasper and the other for the camera. One 12-mm port is inserted for the flexible 10-mm ultrasound probe and the endoscopic stapler. The patient has CO(2) insufflation to create a 5-mm Hg pneumothorax. Twenty mL/kg of normal saline is introduced into the chest cavity for acoustic coupling. The ultrasound probe is used to isolate the nodule(s), guide resection, and check margins. The specimen is removed and placed in a removable specimen bag to reduce the chance of port site recurrence. After the lung has been inspected, irrigation is removed, and a chest tube inserted.

RESULTS

Eight procedures were performed on 7 patients (5 males, 2 females) with a median age of 15.2 years (range, 4-18 years). Patients had primary diagnoses of osteosarcoma (n = 4), Wilms' (n = 2), and lymphoma (n = 1). The median size of the lesions that were being isolated was 0.6 cm (range, 0.3-2.9 cm). None of the nodules removed were visible on the surface of the lung. Of the 8 procedures, 7 led to the removal of a pulmonary nodule. Of the 7 nodules isolated, 5 were removed thoracoscopically, with two requiring minithoracotomy because of anatomical limitations. The histologic evaluation on these specimens included osteosarcoma (n = 4), abscesses (n = 2), fibrosis (n = 1), and lymph node (n = 1). The median hospitalization was 2.5 days (range, 2-39 days). One patient had a prolonged hospitalization because of air leak and sepsis.

CONCLUSION

Minimally invasive thoracoscopic ultrasound is a real time imaging tool that helps isolate small pulmonary lesions that may otherwise be difficult to see intraoperatively. We would advocate this technique for those patients having video-assisted thoracoscopy to assist clarifying whether focal lesions are malignant, thereby guiding therapy.

Lung metastases in neuroblastoma at initial diagnosis: A report from the International Neuroblastoma Risk Group (INRG) project

BACKGROUND

Neuroblastoma is the most common extracranial pediatric solid cancer. Lung metastasis is rarely detected in children with newly diagnosed neuroblastoma. We aimed to describe the incidence, clinical characteristics, and outcome of patients with lung metastasis at initial diagnosis using a large international database.

PROCEDURE

The subset of patients from the International Neuroblastoma Risk Group database with INSS stage 4 neuroblastoma and known data regarding lung metastasis at diagnosis was selected for analysis. Clinical and biological characteristics were compared between patients with and without lung metastasis. Survival for patients with and without lung metastasis was estimated by Kaplan-Meier methods. Cox proportional hazards methods were used to determine the independent prognostic value of lung metastasis at diagnosis.

RESULTS

Of the 2,808 patients with INSS stage 4 neuroblastoma diagnosed between 1990 and 2002, 100 patients (3.6%) were reported to have lung metastasis at diagnosis. Lung metastasis was more common among patients with MYCN amplified tumors, adrenal primary tumors, or elevated lactate dehydrogenase (LDH) levels (P < 0.02 in each case). Five-year overall survival +/- standard error for patients with lung metastasis was 34.5% +/- 6.8% compared to 44.7% +/- 1.3% for patients without lung metastasis (P = 0.0002). However, in multivariable analysis, the presence of lung metastasis was not independently predictive of outcome.

CONCLUSIONS

Lung metastasis at initial diagnosis of neuroblastoma is associated with MYCN amplification and elevated LDH levels. Although lung metastasis at diagnosis was not independently predictive of outcome in this analysis, it remains a useful prognostic marker of unfavorable outcome.

Generation and characterization of novel local and metastatic human neuroblastoma variants

Neuroblastoma (NB) is the most commonly occurring solid tumor in children. The disease usually arises in the adrenal medulla, and it is characterized by a remarkable heterogeneity in its progression. Most NB patients with an advanced disease have massive bone marrow infiltration at diagnosis. Lung metastasis represents a widely disseminated stage and is typically considered to be a terminal event. Much like other malignancies, NB progression is a complex, multistep process. The expression, function, and significance of the various factors involved in NB progression must be studied in relevant in vivo and in vitro models. Currently, models consisting of metastatic and nonmetastatic cell variants of the same genetic background exist for several types of cancer; however, none exists for NB. In the present study, we describe the generation of a NB metastasis model. SH-SY5Y and MHH-NB-11 NB cells were inoculated orthotopically into the adrenal glands of athymic nude mice. Neuroblastoma cells metastasizing to the lungs were isolated from mice bearing adrenal tumors. Lung metastatic variants were generated by repeated cycles of in vivo passage. Characterization of these variants included cellular morphology and immunophenotyping in vitro, aggressiveness in vivo, and various biologic parameters in vitro. The NB metastatic variant in each model displayed unique properties, and both metastatic variants demonstrated a metastatic phenotype in vivo. These reproducible models of human NB metastasis will serve as an unlimited source of transcriptomic and proteomic material. Such models can facilitate future studies on NB metastasis and the identification of novel NB biomarkers and targets for therapy.

Pediatric pulmonary tumors: primary and metastatic

Pediatric pulmonary tumors are rare. There is often a significant delay in diagnosis of pulmonary tumors secondary to their rarity and nonspecific presenting physiologic and radiographic findings. A high index of suspicion in pediatric patients with recurrent or persistent pulmonary symptoms is of paramount importance in diagnosing pulmonary tumors at an early stage. Malignant pulmonary tumors are more frequently diagnosed than benign lesions, with metastatic cancers being the most common. Complete surgical resection remains the basis of therapy for primary lesions, and its role in secondary cancers is becoming more established. Adjuvant therapies are frequently employed depending on the precise tumor involved. Mortality rates vary greatly depending on tumor location, stage, and type.

Significance of pleural effusion in neuroblastoma

BACKGROUND

Pleural effusion is uncommon at diagnosis of neuroblastoma in children. Because the presence of malignant cells in pleural fluid may significantly change the management and outcome of patients with neuroblastoma, we retrospectively analyzed a cohort of neuroblastoma patients who presented with pleural effusion at the time of diagnosis to determine the incidence, presentation, stage, treatment, and outcome of these patients.

METHODS

We reviewed the presenting features of 295 patients with the diagnosis of neuroblastoma who received treatment at St. Jude Children's Research Hospital between 1991 and 2005. Patients were chosen for further analysis if pleural effusion had been identified on chest radiographs or computed tomography (CT) scans at diagnosis

RESULTS

Thirty-one out of 295(10.5%) patients with neuroblastoma had pleural effusion identified at time of presentation. International neuroblastoma staging system (INSS) risk stratification was high risk in 29 cases and intermediate risk and low risk in 1 case each. The primary site of disease was abdomen in 26 patients; mediastinum in 5. We conducted cytologic analysis of pleural fluid of nine patients; the specimen of seven contained malignant cells. Eighteen of 31 patients died of progressive or recurrent disease.

CONCLUSION

In patients with neuroblastoma, pleural effusion is usually associated with unfavorable biologic features and high-risk disease. Pleural fluid should be examined cytologically and at a time when the results would change the risk stratification. There was no statistically significant difference in the survival rate of the patients with high-risk neuroblastoma with or without malignant pleural effusion.

Pulmonary metastasectomy in pediatric patients

This article describes the historical development of pediatric pulmonary metastasectomy but demonstrates that progress has been slow in understanding its proper applications. Because many pediatric metastatic tumors are rare, surgeons have grouped together patients of different histologies for the generation and analysis of case series. By examining tumor types individually, however, it is seen that certain histologies (adrenocortical carcinoma, alveolar soft part sarcoma, osteosarcoma) mandate surgical metastasectomy for patient survival. Other pediatric tumors (Wilms tumor, Ewing's sarcoma) are radiation sensitive, and the application of metastasectomy is controversial. In the case of still other types of tumor (neuroblastoma, differentiated thyroid cancer, rhabdomyosarcoma), metastasectomy is seldom performed except in highly unusual situations. Techniques for minimally invasive biopsy and for muscle-sparing thoracotomy are described for pediatric patients.

[Modern diagnosis of lung nodules]

Despite numerous technical improvements, modern diagnosis of lung nodules can still be divided into three partially overlapping stages: (1) detection, (2) characterization, and (3) follow-up and management. With respect to these steps, this article reviews the diagnostic significance of different modalities. New and not definitively evaluated techniques are considered. Furthermore, methods that are not routinely applied but have been published and are thought to have some value in the characterization of pulmonary lung nodules are discussed. Statistical data are included to assist the classification of the results of imaging. Remarks on biopsy of lung nodules to obtain histopathologic correlation complete this overview. The authors are convinced that the established methods (radiography for detection, spiral CT for characterization), after thorough evaluation, will soon be replaced by magnetic resonance imaging (MRI). Recent experience with MRI points to its potential for detection and characterization of pulmonary nodules while avoiding ionizing radiation. The development of indications for MRI of the lung (e.g. paediatric radiology) will be fascinating to observe.

Malignant abdominal masses in children: quick guide to evaluation and diagnosis

A palpable mass in the abdomen of a child is a serious finding. In this article the authors present their single-institution experience of how these malignancies present and their distribution by age and diagnosis. The most common abdominal malignancies diagnosed in the pediatric population include neuroblastoma, Wilms' tumor, hepatoblastoma, lymphoma, and germ cell tumors. This article provides the busy general pediatrician with some guidelines of how to proceed after discovering a suspiciousmass.