CT differentiation of benign and malignant lung nodules in children

The superiority of computed tomography (CT) for detection of lung nodules has been documented and attempts have been made to distinguish benign from malignant lesions in adults. We attempted to characterize lung nodules in 12 children with solid malignant tumors (aged 8 months to 17 years) in an effort to differentiate benign from metastatic disease. All scans were performed at 10-mm contiguous intervals on a GE 9800 CT scanner. The scans were retrospectively viewed by two pediatric radiologists independently and without knowledge of the pathological findings. All biopsies were done via open thoracotomy. The CT findings were correlated with pathology results. Twelve children had 13 nodules biopsied. Six of these showed malignancy, two showed inflammatory changes, and two had a reactive subpleural lymph node. In three children, no abnormality was found and a biopsy was not obtained. One child had a metastatic nodule in one lung, and a simultaneous inflammatory nodule in the other. The radiologists agreed with each other on the CT interpretation in 11 of 13 surgically explored areas. They correctly predicted malignancy in four cases and correctly excluded it in two cases. However, they were simultaneously incorrect in five instances. Our conclusion is that, contrary to reports in adults, a tiny nodule may be either benign or malignant. Malignancy cannot be separated from benign disease by CT established criteria.