Most Likely Diagnosis: Neuroblastoma
For a patient presenting with lower-limb weakness and a paravertebral mass on CT, neuroblastoma is the most likely diagnosis. 1
Rationale Based on Anatomic Location
Neuroblastoma is the most common tumor in the paravertebral compartment, arising from sympathetic ganglia along the spine with a characteristic paravertebral location. 1 Neurogenic tumors, including neuroblastoma, represent the most frequent masses found in the paravertebral compartment. 2, 1
The combination of:
- Paravertebral mass location (classic for neuroblastoma) 1
- Lower-limb weakness (indicating spinal cord compression from the mass) 3, 4
This clinical presentation is pathognomonic for neuroblastoma causing cord compression, which occurs in up to 67.7% of pediatric paravertebral tumor cases. 5
Why Other Options Are Incorrect
Wilms Tumor (Option B)
- Wilms tumor is a renal mass, not a paravertebral mass
- It arises from kidney parenchyma and would present as a flank or abdominal mass, not in the paravertebral region
Retinoblastoma (Option C)
- Retinoblastoma is an intraocular tumor affecting the retina
- It has no anatomic relationship to the spine or paravertebral region
- Presents with leukocoria (white pupillary reflex) and vision changes, not lower-limb weakness
Hepatoblastoma (Option D)
- Hepatoblastoma arises from the liver and presents as a hepatic mass, not a paravertebral mass, making it incompatible with this clinical scenario. 1
- Would present with abdominal distension and elevated alpha-fetoprotein, not spinal symptoms
Age-Based Diagnostic Considerations
For patients < 5 years old, a destructive bone lesion or paravertebral mass should be interpreted predominantly as either metastatic neuroblastoma or Langerhans cell histiocytosis (LCH). 2 The presence of lower-limb weakness from cord compression strongly favors neuroblastoma over LCH in this context. 6, 5
Clinical Presentation Pattern
Neuroblastoma with cord compression typically presents with:
- Pain (62.5-64.3% of cases) 6, 5
- Motor dysfunction/weakness (42.8-53.6%) 6
- Sphincter dysfunction (35.7%) 6, 5
- Palpable paravertebral mass (32.1%) 6
The lower-limb weakness in this case represents spinal cord compression (SCC), which is an oncologic emergency requiring immediate intervention. 3, 6, 5
Diagnostic Confirmation
MIBG scan can help confirm neuroblastoma diagnosis and identify metastatic disease once the diagnosis is suspected. 1 However, MRI of the complete spine is the preferred initial imaging modality to assess the extent of cord compression and guide urgent treatment decisions. 2
Critical Management Point
Chemotherapy should be initiated urgently for neuroblastoma with cord compression, as it can produce immediate clinical improvement within 24 hours of starting treatment. 3 This approach avoids the adverse late effects of radiation therapy and surgery while effectively treating the chemosensitive tumor. 6, 5