A careful and thorough physical examination is critical; blood pressure for hypertension, complete neurologic examination to detect Horner’s syndrome, symptoms of spinal cord compression or abnormal movements such as opsoclonus, myoclonus, or ataxia to indicate OMS, skin nodules, or hepatomegaly for 4s disease, and proptosis to indicate a high-risk patient with orbital metastasis, thoracic, abdominal, or pelvic mass. Baseline laboratory studies should include CBC with differential and platelet, liver function tests, creatinine, serum LDH, ferritin, and urinalysis [29, 31]. The diagnosis of neuroblastoma requires the involvement of pathologists who are familiar with childhood tumors. Some neuroblastomas cannot be distinguished from other small round blue cell tumors of childhood, such as lymphomas, primitive neuroectodermal tumors, and rhabdomyosarcomas, using conventional light microscopy and routine H&E staining. Evidence for sympathetic neuronal differentiation may be demonstrated by immunohistochemistry, or by finding elevated levels of urine catecholamine metabolites, such as vanillylmandelic acid (VMA) or homovanillic acid (HVA), although 5–10 % of neuroblastomas do not secrete catecholamines [32].

Surgical management of a child with suspected neuroblastoma should be thoroughly reviewed and discussed with the pediatric oncology team prior to taking the child to the operating room. In general, a limited initial open biopsy to obtain an adequate specimen for diagnostic and analysis of available prognostic markers should be considered [33]. Extensive upfront surgical resection and surgical laminectomy should be limited as this may result in delay in appropriate chemotherapy and potentially result in avoidable surgical complications [34].

Disseminated disease is predictive and prognostic of poor outcome in children with neuroblastoma. Its accurate and sensitive assessment can facilitate optimal treatment decisions. The International Neuroblastoma Risk Group (INRG) Task Force has defined standardized methods for the determination of minimal disease by immunocytology and quantitative reverse transcriptase-polymerase chain reaction using disialoganglioside GD2 and tyrosine hydroxylase mRNA, respectively. One of the most common sites of metastasis in high-risk neuroblastoma is the bone marrow. Due to the heterogeneity of the bone marrow infiltration, it is critical to obtain multiple biopsies to detect neuroblastoma clusters. Unfortunately, the cytological and histological techniques lack sensitivity and standardization. Recently, the INRG group published its consensus criteria for the detection of neuroblastoma cells in bone marrow, peripheral blood (PB), and peripheral blood stem cells [35]. The objective of the International Risk Group Classification (INRG) is to develop standardized procedures to ensure the consistency of the results and allow comparisons between institutions.

Treatment for children with neuroblastoma is guided by appropriate disease staging at time of initial diagnosis. Therefore, clinical staging should include:

The biopsy specimen must be handled with conditions that allow for relative sterility. The specimen should be fresh and not fixed in formalin. Genetic and molecular studies require at least 100 mg tissue. Specimens can be divided into following manner for appropriate diagnostic evaluations:

Fixed specimens can be evaluated for a structural study. A trained pathologist with experience in childhood solid tumors is critical to appropriate processing of tissue and selection of critical diagnostic immunohistochemical testing on the tumor specimen. Histological classification using the International Neuroblastoma Pathology Committee (INPC) guidelines will help guide risk stratification, using tumor category, MKI, and degree of differentiation [37]. Distinguishing neuroblastoma tumors from other small round blue cell tumors can be made using immunohistochemistry if the urine catecholamine is negative or unavailable [38].

Pathology report should include the following data:

The histological data obtained in a metastasis should correlate with the primary tumor and should be indicated in the report. On the contrary, after chemo treatments and/or radiotherapy histology varies greatly from area to area and there are frequent areas of necrosis and calcification; this is not relevant for prognostic assessment. Occasionally, the diagnosis of neuroblastoma may be challenging on a simple H&E staining, especially for the undifferentiated histology. The differential diagnosis should include lymphomas and leukemias, soft tissue sarcomas, and PNET/Ewing. Immunohistochemistry staining can be utilized to help guide appropriate diagnosis and management [38].

European and North American cooperative groups have selected various factors to define the risk in patients with neuroblastoma, but these have not been uniform, for example: The International Society of Pediatric Oncology Europe Neuroblastoma Group (SIOPEN) uses age, image-defined surgical risk factor (IDRF), and MYCN status for risk assignment in local/regional tumors, on the other hand, the Children’s Oncology Group (COG) uses age, postsurgical stage, MYCN status, DNA ploidy, loss of heterozygosity at 11q, 1p, and histology [1, 47]. Estimated 5-year survival rates for patients with non-high-risk and high-risk neuroblastoma are 90 and 50 %, respectively. Recent clinical trials have shown excellent outcomes with reduced therapy for non-high-risk disease. For patients with high-risk neuroblastoma treated with chemo radiotherapy, surgery, and stem cell transplantation, the addition of anti-disialoganglioside GD2 immunotherapy plus cytokines improves survival. Upcoming trials will study the incorporation of targeted radionuclide therapy prior to myeloablative chemotherapy into high-risk treatment [48].

A new staging system (INRG) was developed for neuroblastoma risk assignment and stratification of patients at the time of diagnosis and prior to initiating treatment (Table 23.1). This staging incorporates the extension of local, regional disease as the presence or absence of image-defined presurgical risk in L1 and L2 tumors; disseminated disease is categorized as M stage, with the exception of Ms stage, which defines the presence of metastatic disease limited to the skin, liver, bone marrow without commitment to the cortical bone, in children between the ages of 0–18 months with small primary tumors. Additional evaluations that have been recommended are molecular diagnostic tests in the tumor tissue, bone marrow analysis, and radiographic imaging [15] (Table 23.2.). Because the treatment effect of tumor excision is an inherent part of the INSS, the prognostic value of specific stages within INRGSS and INSS cannot be directly compared. The INRGSS differs from INSS in four important ways. First, it is based on preoperative imaging and image-defined risk factors (IDRFs), not surgicopathologic findings. Second, the midline is not included in the staging criteria of the INRGSS. Third, lymph node status is not included in the staging of localized disease. Fourth, whereas INSS stage 4S has an upper age limit of 12 months, the Task Force decided to extend the age group for stage MS to patients younger than 18 months. The INRGSS is a preoperative staging system that has been developed specifically for the INRG classification system. The extent of disease is determined by the presence or absence of IDRFs and/or metastatic tumor at the time of diagnosis, before any treatment. Use of this pretreatment staging system and the INRG classification system will facilitate the ability to compare results of risk-based clinical trials conducted in different regions of the world, and thereby, provide insight into optimal treatment strategies for patients with neuroblastic tumors [49].

In the resource-limited countries (RLC), there are significant limitations in the diagnosis of neuroblastoma. The majority of the centers in these countries do not have the resources to obtain all the biological and genetic data that is suggested for a complete treatment stratification and therapy assignment. Therefore, a modified stratification is typically considered based on resource availability with current use of the INSS system.