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.

Purpose: To review a historical cohort of childhood ganglioneuroma (GN), the benign representative of the peripheral neuroblastic tumor (PNT) family. Patients and Methods: Of 2,286 PNTs enrolled between 1979 and 2005, 146 (6.4%) were registered as GN. Histological revision was carried out on 76 tumors. Diagnosis was confirmed in 45, while 27 were reclassified as ganglioneuroblastoma intermixed (GNBI) and four were reclassified as other PNT subtypes. Results: GNs differed from other PNTs for sex, age, tumor site, stage, tumor markers, and scintigraphic results. Characteristics of 76 reviewed and 70 nonreviewed patients were comparable. Reviewed GN and GNBI patients were comparable except for homovanillic acid excretion, metaiodobenzylguanidine scintigraphy, and DNA content. Seven patients were only biopsied and 139 underwent surgery. Twenty-two patients suffered surgery-related complications, of which two were fatal and seven were severe. Radical tumor resection and surgery-related complication rates were comparable for GN, GNBI, and nonreviewed instances. Six patients developed tumor progression but survived. Two patients developed a late malignancy but survived. None of the 146 patients received chemotherapy. Of 146 patients, two died of surgery-related complications and 144 survived. Conclusion: Diagnosis was changed to GNBI for approximately one third of 76 reviewed tumors. Patients with confirmed GN, reclassified as GNBI, and nonreviewed histology presented with comparable clinical, biochemical, and biologic features. Surgical results, complication rate, number of progressions, and outcome were similar for the three groups. Surgery was associated with significant risk of complications. Survival was not influenced by extent of tumor resection. Aggressive surgical approach should not be recommended for childhood GN and GNBI.

Lymphomas account for 10%-15% of all childhood cancers and include a number of different pathologic subtypes, which arise from the constituent cells of the immune system or from their precursors. All organ systems may be involved at some stage of the disease, including the central nervous system, head and neck, thorax, abdomen, gonads, and bone. However, at onset, nodal and splenic involvement are more common in Hodgkin disease, whereas extranodal involvement is more frequent in non-Hodgkin lymphomas. Diagnostic imaging modalities have a fundamental role in the staging of lymphomas and, owing to major advances during the past two decades, make surgical staging unnecessary in most cases. Conventional, sonographic, and cross-sectional imaging techniques are excellent tools for evaluating the extent and sites of disease in childhood lymphomas. Familiarity with the spectrum of imaging findings in lymphomas is essential for radiologists to enable them to provide guidance for the treating physicians.