Pulmonary nodules discovered during the initial evaluation of pediatric patients with bone and soft-tissue sarcoma

Background. Recent technical advances in CT imaging and data processing have improved the ability to detect small pulmonary nodules in children with bone and soft-tissue sarcoma undergoing radiologic imaging of the chest. Procedure. We retrospectively studied medical records and CT chest scans at initial diagnosis of 210 children and young adults presenting to a single pediatric tertiary care hospital specialized in oncology for evaluation of bone or soft-tissue sarcoma. We correlated clinical features and CT scan findings with patient outcome and histologic results, when available. Results. Pulmonary nodules (diameter ≤3 cm) were identified in 66 patients (31.4%). The median size of the largest nodule in each patient was 5 mm (range, 1-20 mm). Of patients who underwent biopsy or resection of a nodule, 41.7% had metastatic pulmonary disease. Having more than three nodules and a bilateral distribution were associated with histology-proven metastasis (P= 0.002 and P = 0.011, respectively) and an increased frequency of recurrent or progressive metastatic disease in the lung (P< 0.001 and P = 0.023, respectively). Greater size of the largest nodule present showed a trend towards biopsy-proven lung metastasis, but did not reach statistical significance (P= 0.06). When biopsy or resection was not performed, increased size was significantly associated with nodules being presumed as malignant (median, 16.8 mm compared to 4.0 mm for biopsied nodules, P< 0.001). Conclusions. Pulmonary nodules were commonly detected during the initial evaluation of pediatric cases of sarcoma. Number and distribution of nodules were significantly associated with metastatic disease and outcome.