Do characteristics of pulmonary nodules on computed tomography in children with known osteosarcoma help distinguish whether the nodules are malignant or benign?

PURPOSE

To determine if selected computed tomography (CT) characteristics of pulmonary nodules in pediatric patients with osteosarcoma can help distinguish the nodules as benign or malignant.

METHODS

The institutional review board approved this HIPAA (Health Insurance Portability and Accountability Act-compliant, retrospective study of 30 pediatric osteosarcoma patients (median age 14 years, range 8-22) who underwent chest CT with resection of 117 pulmonary nodules from January 2001 to December 2006. Two pediatric radiologists and one chest radiologist independently and retrospectively reviewed the CT scans and classified nodules as benign, malignant, or indeterminate on the basis of nodule size, laterality, number, location, growth, density, margin appearance, and calcification. Generalized estimating equations were used to examine which characteristics were independent predictors of nodule malignancy.

RESULTS

Of the 117 nodules, 80 (68%) were malignant and 37 (32%) were benign by pathologic review. The readers correctly classified 93% to 94% of the malignant nodules. For benign lesions, the results were not as accurate, with the readers correctly classifying only 11% to 30% of lesions. Most of the benign lesions were classified as indeterminate by the readers (54%-65%). Nodule size (≥5 mm) and the presence of calcifications were associated with an increased probability of malignancy (P b .05).

CONCLUSION

On chest CT, nodule size 5 mm or greater and the presence of calcifications are associated with an increased probability of malignant nodule histology in pediatric patients with osteosarcoma. However, nodule characteristics, apart from size and calcification, at chest CT cannot reliably distinguish benign from malignant pulmonary nodules in these patients.