CROSS-SECTIONAL IMAGING WITH CT AND OR MRI OF PEDIATRIC CHEST TUMORS/

The purpose of this study was to provide an overview of the spectrum o f pediatric chest masses, to present the results of cross-sectional im aging with CT and/or MRI, and to define diagnostic criteria to limit d ifferential diagnosis. Seventy-eight children with thoracic mass lesio ns were retrospectively evaluated using CT (72 patients) and/or MR ima ging (12 patients). All masses were evaluated for tissue characteristi cs (attenuation values or signal intensity, enhancement, and calcifica tion) and were differentiated according to age, gender, location, and etiology. Twenty-eight of 38 (74 %) mediastinal masses were malignant (neuroblastoma, malignant lymphoma). Thirty of 38 (79 %) pulmonary mas ses were metastatic in origin, all with an already known primary tumor (osteosarcoma, Wilms tumor). With one exception, all remaining pulmon ary lesions were benign. Seventeen :of 21 (81 %) chest wall lesions we re malignant (Ewing sarcoma, primitive neuroectodermal tumor). The maj ority of mediastinal and chest wall tumors in children is malignant. L ung lesions are usually benign, unless a known extrapulmonary tumor su ggests pulmonary metastases. Cross-sectional imaging with CT and/or MR I allows narrowing of the differential diagnosis of pediatric chest ma sses substantially by defining the origin and tissue characteristics. Magnetic resonance imaging is preferred for posterior mediastinal lesi ons, whereas CT should be used for pulmonary lesions. For the residual locations both modalities are complementary.