Computed tomography in the diagnosis and treatment of mediastinal abnormalities in children.

Thirty-one children with mediastinal abnormalities--14 malignant lymphomas, 4 other primary malignancies, one metastatic and 12 benign lesions--were examined one or several times using CT, which proved to be effective especially for cysts (5 patients), ductus arteriosus aneurysm (2 patients), and intrathoracic liver (one patient). It also supplied important diagnostic information regarding the extent of disease in malignant thymoma (one patient), in neurinoma (one patient), and in Hodgkin's lymphoma (5 patients). It was found to be useful in the monitoring of treatment of patients with lymphomas, in which a small residue, probably a fibrotic remnant, was invariably seen after completion of chemotherapy and irradiation. It was concluded that when the residue was enlarged, the possibility of relapse and even thymic hyperplasia should be considered. However, if CT was performed under general anaesthesia pseudo-widening of the anterior mediastinum could simulate recurrence. Surgical biopsy was found to be necessary in these cases because fine-needle aspiration biopsy was unsuccessful.