Great vessel/cardiac extension and tumor embolism in pleuropulmonary blastoma: A report from the International Pleuropulmonary Blastoma Registry

Background: Types II and III pleuropulmonary blastoma (PPB) are aggressive sarcomas of lung and pleura in young children. Similar to cavoatrial extension of Wilms tumor, PPB may extend into thoracic great vessels and the heart and may involve both venous and arterial circulations and right and left cardiac chambers. Serious embolic complications occur. Procedure: Review International PPB Registry databases and literature (1) for PPB cases with vascular/cardiac extension and (2) for neoadjuvant chemotherapy results in vascular extension cases. Results: Among 179 Registry-confirmed and approximately 200 literature Type II and III PPB cases, 11 examples (approximately 3%) of great vessel/cardiac extension were identified; 1 case is presented in detail. Nine cases involved the left circulation, one the right and one both. Various radiographic techniques including echography, computed tomography and gated magnetic resonance imaging identified vascular tumor. Seven children had arterial embolic events: cerebrovascular accidents (six, including one femoral artery occlusion) and acute aortic occlusion (1). Six of these seven died from complications that may be attributed to vascular involvement. In three of four children with vascular involvement, neoadjuvant chemotherapy lessened the involvement; in one the effect could not be assessed. None of these four had embolic events. Effect on survival could not be assessed due to small numbers. Conclusions: Involvement of thoracic great vessels and the heart is a serious complication of PPB, with fatal embolic complications possible. Radiographic evaluation of the central circulation should be performed in children with suspected or diagnosed PPB to identify this complication.