Pediatric mediastinal masses

Pediatric mediastinal masses are the most common chest masses in children, with the anterior mediastinum being the most common site .

As in adults, mediastinal masses are classified depending on anatomical sites:

• anterior mediastinal masses
• middle mediastinal masses
• posterior mediastinal masses

Anterior mediastinal masses

Basic approach to these lesions is by chest radiograph (PA and lateral) for localization followed by contrast-enhanced CT for characterization:

• malignant lymphoma (Hodgkin and non-Hodgkin) - most common
• teratoma - common
• thymus (benign enlargement) - common
• thyroid (retro- or sub-sternal extension)
• thymic cyst
• angioma
• langerhans cell histiocytosis
• mesenchymal tumors
• lymphangioma (cystic hygroma) - generally extends from neck into mediastinum

Middle mediastinal masses

Basic approach to these lesions is by chest radiograph (PA and lateral) for localization, with barium swallow to identify areas of compression followed by contrast-enhanced CT for characterization:

• foregut duplication cyst (bronchogenic, enteric, and neuroenteric) - most common; bronchogenic cyst is more common
• lymphadenopathy
• vascular malformations

Posterior mediastinal masses

Basic approach to these lesions is by chest radiograph (PA and lateral) for localization followed by MRI for evaluation of intraspinal extension of neurogenic tumors and distinction between vascular structures and soft tissues. Contrast-enhanced CT can be carried out when MRI is not available:

• neurogenic tumor - most common
• foregut duplication cyst
• vascular malformations
• extramedullary hematopoiesis