pediatrics
Neuroblastoma
Diagnosis of Neuroblastoma
CT/MRI Biopsy Sometimes bone marrow aspirate or marrow core biopsy plus measurement of urinary catecholamine intermediates Routine prenatal ultrasonography occasionally detects neuroblastoma. Patients presenting with abdominal symptoms or a mass require CT or MRI. Diagnosis of neuroblastoma is then confirmed by biopsy of any identified mass. Alternatively, diagnosis can be established without biopsy or surgery of the primary tumor by finding characteristic cancer cells in a bone marrow aspirate or core biopsy plus elevated urinary catecholamine intermediates. These methods of diagnosis are not commonly done but can be useful in situations where biopsy and/or surgery is considered high risk because of patient or tumor characteristics. 90% of patients. A 24-hour urine collection can be used, but a spot urine test is usually sufficient. If the primary site of the neuroblastoma is adrenal, it must be differentiated from Wilms Tumor and other renal masses. It may also need to be differentiated from The following should be done to evaluate for metastases: Bone marrow aspirates and marrow core biopsies from multiple sites (typically, both posterior iliac crests) Bone scan or iodine-131 metaiodobenzylguanidine (MIBG) scan (MIBG uptake occurs in > 90% of neuroblastomas) Abdominal, pelvic, and chest CT or MRI Cranial imaging with CT or MRI is indicated if symptoms or signs suggest brain metastases. Results of these tests determine stage (extent of spread) of disease. TheInternational Neuroblastoma Staging System(INSS) requires the results of surgery to determine stage. TheInternational Neuroblastoma Risk Group Staging System(INRGSS) uses imaging-defined risk factors rather than surgery to stage neuroblastoma. Neuroblastoma also has a unique stage called stage 4S (per INSS) or MS (per INGRSS) that often regresses spontaneously without treatment. This stage includes children < age 12 months (4S) or 18 months (MS) who have a localized primary tumor that has dissemination limited to skin, liver, and/or bone marrow. Marrow involvement should be minimal and limited to < 10% of the total nucleated cells and cannot involve the cortex of the bone. At diagnosis, attempts should be made to obtain adequate tumor tissue to analyze for DNA index (the ratio of the amount of DNA in a tumor cell to the amount in a normal cell; the DNA index is thus a quantitative measure of chromosome content) and amplification of theMYCNoncogene. After staging, the staging information, along with other known prognostic factors, including patient age, histology,MYCNamplification, molecular information from the tumor, and DNA index, is used to categorize patients to guide treatment intensity and determine the prognosis for and likelihood of a recurrence of disease after treatment. Risk categorization is complex, andtwo major risk group stratification systems exist, the Children's Oncology Group (COG) risk group and the International Neuroblastoma Risk Group (INRG) classification. In both systems, the staging and prognostic factors are used to stratify patients into low-, intermediate-, and high-risk categories that help determine prognosis and guide treatment. In addition, chromosome 11q aberrations are considered in the INRG classification. 