A 13-YEAR-OLD girl presented with a 3-day history of chest and left arm pain. She denied cough, fever, weight loss, fatigue, or other symptoms. Physical examination was remarkable for mild jugular venous distension, dyspnea, and decreased breath sounds on the left side. There was no lymphadenopathy or hepatosplenomegaly. Serum electrolyte levels and the results of liver function tests were normal. Hematologic parameters revealed a mild polymorphonuclear leukocytosis and an elevated erythrocyte sedimentation rate. Chest roentgenograms were obtained (Figure 1). Pleural and pericardial effusions were present and believed to indicate superior mediastinal obstruction. Computed tomography was performed (Figure 2) and was followed by a technically difficult and inconclusive mediastinal biopsy guided by computed tomography.
During the next 24 hours, progressive respiratory distress and fever developed. Broad-spectrum intravenous antimicrobial therapy was initiated. A rapidly expanding mediastinal malignancy was suspected and she was given two empiric radiation treatments to the mediastinum at