Large intrathoracic tumors in children: imaging findings.

Massive benign or malignant thoracic tumors in children may arise from the chest wall, pleura, lung parenchyma, or mediastinum and may be primary or secondary. On initial chest radiographs, these masses usually appear as an opaque hemithorax or an obvious large opaque mass. If the site of origin of the intrathoracic tumor can be determined, the differential diagnosis may be based on the location of the tumor, the age of the patient, and distinguishing imaging features. The purpose of this essay is to illustrate imaging findings of large intrathoracic masses that cause an opaque hemithorax on initial chest radiographs. Chest wall masses that do not grow primarily intrathoracically are not included in this discussion.