Thoracic neuroblastoma : what is the best imaging modality for evaluating extent of disease ?

Thoracic neuroblastoma accounts for 15% of all cases of neuroblastoma. A minority of children with thoracic neuroblastoma will have dumbbell tumors, i.e., intraspinal extension, but only half these patients will have neurologic signs or symptoms. MR imaging is the single best test to evaluate the extent of thoracic and spinal disease in thoracic neuroblastoma after the diagnosis of a mass is established on plain film. A retrospective multi-institutional investigation over 7 years of all cases of thoracic neuroblastoma (n = 26) imaged with CT and/or MR were reviewed for detection of the extent of disease. The chest film, nuclear bone scan, and other imaging modalities were also reviewed. The surgical and histologic correlation in each case, as well as the patients' staging and outcome, were tabulated. The chest radiograph was 100% sensitive in suggesting the diagnosis. MR imaging was 100% sensitive in predicting enlarged lymph nodes, intraspinal extension, and chest wall involvement. CT was 88% sensitive for intraspinal extension but only 20% sensitive for lymph node enlargement. CT was 100% sensitive in detecting chest wall involvement. Direct comparison of CT and MR imaging in six cases revealed no difference in detection of enlarged lymph nodes or chest wall involvement. Neither test was able to detect remote disease, as noted by bone scan. The chest film is 100% sensitive in suggesting the diagnosis of thoracic neuroblastoma; MR imaging appears to be the single best test for detecting nodal involvement, intraspinal extension, and chest wall involvement.