Radiologic-pathologic conference of Children's Hospital Boston: new pulmonary nodules in a child undergoing treatment for a solid malignancy.

The appearance of pulmonary nodules in a child with a solid malignancy undergoing chemotherapy is a clinically worrisome event. The diagnosis in such cases is not always metastatic disease, and the differential diagnosis should include granulomatous disease, atelectasis, pneumonia, inflammatory pseudotumor, hamartoma, radiation pneumonitis, and bronchiolitis obliterans with organizing pneumonia. There is no consistent radiologic feature to help distinguish benign from malignant causes of these new lesions. However, repeat chest CT 4-6 weeks after the lesions are first noted can be used to track lesion progression and may obviate the need for biopsy.