The Most Common Posterior Mediastinal Mass in Children
The answer is (a) neuroblastoma—neurogenic tumors, particularly neuroblastoma, are the most common posterior mediastinal masses in children.
Evidence-Based Rationale
The American College of Radiology guidelines clearly establish that neurogenic tumors are most common in the paravertebral (posterior) compartment of the mediastinum 1. This finding is consistently supported across multiple high-quality studies examining pediatric mediastinal masses.
Key Clinical Data
- Neurogenic tumors account for approximately 89% of posterior mediastinal masses in children 2
- Neuroblastoma specifically is the most common neurogenic tumor in this location 2, 3
- Among all posterior mediastinal masses in pediatric patients, 60% are malignant, with neuroblastoma being the predominant malignancy 2
Age-Specific Considerations
Neuroblastoma should be strongly suspected in children younger than 5 years old presenting with a posterior mediastinal mass 4. The median age at diagnosis for posterior mediastinal masses is 6 years, with neuroblastoma being most prevalent in the first years of life 5, 2.
Why Other Options Are Less Common
- Teratoma (option b): These are germ cell tumors that occur primarily in the anterior (prevascular) mediastinum, not the posterior compartment 1, 3
- Lymphoma (option c): This is the most common anterior mediastinal mass in children, not posterior 1, 3
- Pheochromocytoma (option d): While paragangliomas can occur in the mediastinum, they are rare compared to neuroblastoma 1
Clinical Presentation Patterns
Approximately 45% of children with posterior mediastinal masses present with respiratory symptoms or chest pain, while 13% have neurologic symptoms (half related to spinal cord compression) 2. However, 32% are incidental findings on imaging 2.
Diagnostic Approach
When evaluating a posterior mediastinal mass in a child, MRI is particularly helpful for characterizing neurogenic tumors 3. The workup should include chest radiography and cross-sectional imaging (CT or MRI) of the chest and abdomen to assess tumor extent 2.
Prognostic Information
Children diagnosed with neuroblastoma in the first year of life have significantly better survival than those presenting after the first year 2. Overall, 84% of patients with posterior mediastinal masses are alive and disease-free at median follow-up of 45 months 2.