A 2-year-old girl from Delhi presents with a 2-week history of irritability, poor feeding, and constipation. On examination, she is found to have a firm, fixed, right-sided abdominal mass that does not cross the midline. Abdominal ultrasound reveals a 5 cm heterogeneous mass in the right adrenal region with areas of calcification. Urine vanillylmandelic acid (VMA) is elevated at 8.5 mg/24 h (normal <4 mg/24 h). Chest X-ray shows no pulmonary lesions. What is the most appropriate next step in management?

Explanation

## Staging and Risk Stratification in Neuroblastoma **Key Point:** Before any treatment decision (surgery or chemotherapy) in neuroblastoma, **complete staging investigations and risk stratification are mandatory**. This determines prognosis and guides therapy intensity. ### Why Staging Comes First 1. **INSS staging** — Neuroblastoma is staged (I–IV) based on tumor extent, lymph node involvement, and metastases. Staging directly influences treatment intensity and prognosis. 2. **Risk stratification** — Factors such as age, tumor histology (INPC), MYCN amplification, and ploidy determine whether the child is low-, intermediate-, or high-risk. 3. **Treatment planning** — Low-risk tumors may need only surgery; intermediate-risk requires chemotherapy + surgery; high-risk requires intensive multimodal therapy (chemotherapy, surgery, radiation, stem cell transplant). ### Required Staging Investigations | Investigation | Purpose | |---|---| | **MIBG scintigraphy** | Detects bone and soft tissue metastases (gold standard for neuroendocrine tumors) | | **CT chest/abdomen/pelvis** | Assesses local tumor extent, lymph nodes, and distant metastases | | **Bone marrow biopsy/aspirate** | Detects marrow involvement (INSS Stage 4S criterion) | | **Serum ferritin, NSE, LDH** | Prognostic markers; elevated levels suggest poor prognosis | | **MYCN analysis** (FISH/PCR) | Amplification = high-risk; non-amplified = better prognosis | | **Histology/INPC grading** | Favorable vs. unfavorable histology affects risk category | **Clinical Pearl:** This 2-year-old has an adrenal mass with elevated VMA — classic for neuroblastoma. The presence of calcification and fixed mass suggest local invasion. **Stage cannot be assigned without imaging**; she could be Stage I (localized), Stage II (local + ipsilateral nodes), Stage III (crossing midline or contralateral nodes), or Stage IV (distant metastases). MIBG scintigraphy is critical to rule out occult bone/soft tissue metastases. **High-Yield:** The **INSS Stage 4S** (special category) applies to infants <18 months with localized tumor but bone marrow/liver/skin metastases — these often regress spontaneously and may need only observation or minimal therapy. Staging determines this classification. ### Why Not Immediate Surgery? Surgery without staging risks incomplete resection in high-risk disease and denies the child neoadjuvant chemotherapy that could downstage the tumor and improve outcomes. ### Why Not Immediate Chemotherapy? Chemotherapy intensity depends on risk category. Low-risk tumors may not need chemotherapy; giving it empirically risks unnecessary toxicity. ### Why Not Biopsy? Diagnosis is already supported by imaging and elevated VMA. Biopsy adds no diagnostic value and delays staging.