Neuroblastoma is the Most Likely Diagnosis
In a 1-year-old child presenting with lower-limb weakness and a paravertebral mass on CT, neuroblastoma is the most likely diagnosis. This presentation is classic for neuroblastoma with intraspinal extension causing spinal cord compression 1, 2.
Why Neuroblastoma is Most Likely
Age and Location
- Neuroblastoma is the most common tumor in newborns and infants up to 3 months of age, and remains highly prevalent in the first year of life 3
- Paravertebral location is characteristic, as neuroblastoma arises from sympathetic ganglia along the spine 4, 2
- Neurogenic tumors are the most common masses in the paravertebral compartment 4
Classic Presentation Pattern
- Motor dysfunction (weakness) occurs in 42.8% of children with paravertebral neuroblastoma 2
- The typical presentation involves a "dumbbell tumor" configuration—paravertebral mass with intraspinal extension through neural foramina causing cord compression 1
- Lower-limb weakness indicates spinal cord compression at the thoracic or lumbar level, a well-recognized complication of paravertebral neuroblastoma 1, 2
Supporting Clinical Features
- Children with neuroblastoma and spinal involvement commonly present with paralysis or weakness of extremities as the first symptom 1
- Physical examination in these cases typically reveals motor deficits (53.6%), deep tendon reflex alterations (53.6%), and pathologic reflexes (25%) 2
- Pain is present in 64.3% of cases, though not mentioned in this scenario 2
Why Other Diagnoses are Less Likely
Wilms Tumor
- Wilms tumor arises from the kidney, not the paravertebral region 3
- It presents as an abdominal/flank mass, not a paravertebral mass
- Lower-limb weakness would be extremely unusual unless there is massive retroperitoneal extension with nerve root compression
Retinoblastoma
- Retinoblastoma is an intraocular tumor 3
- It has no association with paravertebral masses or lower-limb weakness
- This diagnosis is not relevant to the clinical scenario
Hepatoblastoma
- Hepatoblastoma arises from the liver 3
- It presents as a hepatic mass, not a paravertebral mass
- Lower-limb weakness would not occur unless there is metastatic spinal involvement, which would be extraordinarily rare as a presenting feature
Critical Management Considerations
Urgency of Diagnosis
- Spinal cord compression from neuroblastoma is an oncologic emergency requiring immediate intervention 2
- The degree of neurologic recovery is greatest when symptoms have been present for the shortest duration 1
- Aggressive treatment should be initiated promptly to preserve neurologic function 1, 2
Expected Prognosis
- Age is a critical prognostic factor: 8 of 9 children under 1 year of age with neuroblastoma and paralysis survived in one series, compared to only 1 of 10 children over 1 year 1
- This 1-year-old patient falls into a favorable age category
- Neurologic recovery (partial or full) occurred in 13 of 19 children in one series, with recovery most likely when treatment is initiated early 1
Initial Management Approach
- Corticosteroids with or without chemotherapy should be considered as initial management for cord compression to avoid adverse late effects of radiation therapy and surgery 2
- Laminectomy and tumor excision may be required depending on response to initial therapy 1, 2
- MIBG scan can help confirm neuroblastoma diagnosis and identify metastatic disease 4