A 2-year-old girl from Delhi presents with a 2-month history of progressive abdominal distension and irritability. Her mother reports she has been 'paler than usual' over the past month. On examination, there is a firm, non-tender mass in the left upper quadrant extending across the midline. Hemoglobin is 8.9 g/dL. Abdominal ultrasound reveals a large heterogeneous suprarenal mass with areas of calcification. Urine catecholamine metabolites (VMA and HVA) are markedly elevated. Chest X-ray shows no pulmonary lesions. What is the most appropriate next step in management?

Explanation

## Management of Neuroblastoma: Staging and Risk Stratification **Key Point:** Neuroblastoma requires comprehensive staging (imaging, bone marrow, skeletal survey) and risk stratification before treatment initiation. The International Neuroblastoma Risk Group (INRG) staging system guides intensity of therapy. ### Clinical Presentation and Diagnosis This child has: - **Suprarenal mass** (classic location for neuroblastoma) - **Elevated urinary catecholamine metabolites** (VMA/HVA)—diagnostic hallmark - **Anemia** (suggesting bone marrow involvement or chronic disease) - **No pulmonary metastases** on initial chest X-ray ### Mandatory Staging Workup Before treatment, the following are required: | Investigation | Purpose | |---|---| | **Contrast-enhanced CT chest/abdomen/pelvis** | Assess primary tumor, local invasion, lymph node involvement, distant metastases | | **Bone marrow biopsy (bilateral)** | Detect marrow infiltration (INRG stage M) | | **Skeletal survey ± bone scan** | Identify skeletal metastases | | **123I-MIBG scintigraphy** | Assess soft tissue and skeletal metastases (more sensitive than bone scan) | | **MRI spine** | Evaluate for spinal cord compression or intraspinal extension | **High-Yield:** INRG staging incorporates imaging findings, age at diagnosis, tumor grade, and biologic markers (MYCN amplification, ploidy, histology) to assign risk. Treatment intensity ranges from observation (low-risk) to intensive multimodal therapy (high-risk). ### Risk Stratification Framework **Low-risk disease** (e.g., localized, favorable histology, age < 18 months): - Observation or surgery alone **Intermediate-risk disease** (e.g., localized with unfavorable histology, stage 3): - Surgery + moderate chemotherapy **High-risk disease** (e.g., metastatic, MYCN amplified, age > 18 months): - Intensive multimodal therapy: induction chemotherapy → surgery → consolidation chemotherapy ± radiation ± stem cell transplant **Clinical Pearl:** This child's age (2 years), elevated catecholamines, and suprarenal location are typical for neuroblastoma. The presence of anemia raises concern for bone marrow involvement, which must be confirmed by biopsy before risk assignment. ### Why Immediate Surgery Is Premature - **Incomplete staging** prevents accurate risk assessment - **Spinal cord involvement** (not excluded by ultrasound) could be missed, risking intraoperative catastrophe - **Bone marrow involvement** and metastases must be documented for INRG staging - **Chemotherapy-responsive disease** may benefit from neoadjuvant therapy to reduce operative morbidity ### Why Empirical Chemotherapy Without Staging Is Inappropriate - Treatment intensity must be tailored to INRG risk group - Staging determines whether chemotherapy is indicated at all (low-risk disease may not require it) - Delaying staging investigations while treating risks missing critical prognostic information ```mermaid flowchart TD A[Suspected Neuroblastoma<br/>Suprarenal mass + elevated VMA/HVA]:::outcome --> B[Complete Staging Workup]:::action B --> C["CT chest/abdomen/pelvis<br/>Bone marrow biopsy<br/>Skeletal survey<br/>123I-MIBG scintigraphy<br/>MRI spine"]:::action C --> D{INRG Risk<br/>Stratification}:::decision D -->|Low Risk| E[Observation ± Surgery]:::action D -->|Intermediate Risk| F[Surgery + Chemotherapy]:::action D -->|High Risk| G[Induction Chemotherapy]:::action G --> H[Surgery]:::action H --> I[Consolidation Therapy<br/>± Radiation ± ASCT]:::action F --> J[Surveillance]:::outcome E --> J I --> J ``` **Citation:** [cite:Park 26e Ch Pediatric Malignancies; INRG Staging System]