Large unilateral chest tumors in children.

When large unilateral chest tumors are hidden by pleural fluid collections, or when there is a completely radiopaque hemithorax, ultrasonography is an efficient means of identifying and characterizing a mass. Narrowing of the carinal angle in patients with mediastinal shift is helpful in identifying large intrathoracic tumors that could be mistaken for, or hidden by, large pleural effusions. Of 11 large tumors in children, seven were Ewing's sarcomas, two were metastatic sarcomas, one was a lymphoma, and one was an undifferentiated small cell tumor of unknown origin. The rib lesions of Ewing's sarcoma were seen clearly on chest radiographs in all patients with that disease.