I. Tumor markers 1. 24h urinary VMA: Vanillylmandelic acid (VMA) is a catecholamine metabolite, suggesting the diagnosis. 2.Neuron-specific enolase (NSE): It is mainly used to judge the prognosis and recurrence monitoring. 3.Serum ferritin: It is a prognostic indicator. 4.Lactate dehydrogenase (LDH): elevated level represents rapid transformation, proliferation and high tumor load of tumor cells. Imaging 1.Ultrasound (US): a common means of screening abdominopelvic masses to determine the presence or absence of tumor thrombus in blood vessels, and the presence of calcification in the primary focus is an important feature. 2.Computed axial tomography (CT): It is used to assess the relationship between tumor and blood vessels, the presence or absence of tumor thrombus in blood vessels and the presence or absence of metastasis in substantial organs, and can show calcification well, but it is limited in distinguishing bone marrow metastasis from bone cortex metastasis. 3.Magnetic resonance imaging (MRI): It can well evaluate the intervertebral foramen and epidural invasion, and can distinguish the bone cortex and bone marrow lesions; it can accurately determine the extent of muscle and soft tissue involvement, but has low ability to detect calcification. 3.Bone scan: the tracer is Tc-99m MDP, which is used to evaluate the presence or absence of metastases in the whole body skeleton. Some of the primary foci can show accumulation of Tc-99m MDP, suggesting the presence of calcification. 4.PET/CT: its tracer is FDG, which reflects the strength of metabolic activity. Bone marrow examination 1.Taking site: bilateral anterior superior iliac spine and posterior superior iliac spine, proximal tibia can also be taken in newborns. 2, sampling requirements: two bone marrow aspirations from different sites + two ring drill bone marrow biopsies, biopsy samples containing at least 1 cm of bone marrow tissue in addition to bone cortex and cartilage; or four bone marrow aspirations from different sites. Tissue biopsy 1.Ultrasound or CT-guided aspiration biopsy: quick and less invasive, especially suitable for children with tumor emergencies, but limited sampling and unable to meet molecular biology detection. 2.Surgical excisional resection: select easily accessible primary foci or metastases, and obtain sufficient specimens for molecular biology detection, but it is traumatic, restricted by anesthesia, and relatively slow in diagnosis.