Pleuropulmonary blastoma with vascular invasion.

A 2-year-old gi presented with respiratory distress and clinical findings of superiorvena cava syndrome. An anteroposterior chest radiograph showed a nght thoracic mass and pleural effuskxi (Fig. 1A). Contrast-enhanced CT revealed a large, heterogeneous, right-lung mass with extension into the azygous vein, superior na cava, and right atrium (Figs. lB and 1C). Twodimensional echocardiography (Fig. 1 D) showed the continuity of the pleuropulmonary tumor w medsasthal vascular structures. A right pneumonectomy and mediastinal exploration was performed. A chylous pencardial effusion was drained, the tumor was resected, and the signs of superior vena cava syndrome resolved dramatically. The specimen consisted of a 10 x 7.5 x 6.5 cm right lung mass with a 7.5 x 5.5 x 2.5 cm tumor aggregate extending to the superior vena cava and right atrium. Pathologic diagnosis was poorly differentiated sarcoma consistent with pleuropulmonary blastoma (Figs. 1E, 1 F, and 1G). Pleuropulmonary blastoma is an uncommon embr nal or blastemic neoplasm in children [1 , 2]. It is different from a dassic pulmonary t astoma because of anatomk kcation, primhve t astemk and stromal oomposhon, absence of a carcinomatous component, and potential for sarcomatous differentiation [1 , 2]. Most of the thildren described by Dehner et al. [3] presented w respwatory distress attnbuted to infection or spontaneous pneumothorax. More than 70% of pedents presented with nght-side in .dvement. Two radiographic patterns of disease have been described: multiple peripheral cysts with or without soft-tissue densities and a homogeneous mass with obscuration of the hemithorax. Pneumothorax and pleural effusion may complicate either pattern, and the mediastinum may frequently shift, regardless of the other radiographic changes [3]. Most lesions are in the periphery of the individual lobes, particularly when the neoplasm is exclusively cystic. In 15-25% of cases, the mass is extrapulmonary with attachment to the parietal pleura or with involvement of the diaphragm or mediastinum. When the tumor fills the hemithorax, all contiguous structures, including the great vessels and pericardium, are invaded or infiltrated bytumor. Such tumors weigh 300-1000 g and measure 15-20 cm [3]. Surgery is the preferred treatment of pleuropulmonary blastoma. The prognosis is poor for patients with tumors larger than 5 cm [4]. The survival rate reported by Dehner et al. was 58% (median follow-up, 21 months; range, 1-180 months); 38% died oftumor (one patient was lost to follow-up). The median time to recurrence was 7 months (range, 1-30 months). Such tumors recur locally in the thoracic cavity and metastasize to the ipsilateral and contralateral lobes of the lung and to the central nervous system [3]. A family history of pleuropulmonary blastoma and other childhood neoplasms has been seen in more than 25% of patients [3].