Pulmonary blastoma in a neonate: a lesion distinct from pleuropulmonary blastoma with unique cytogenetic features.

Pulmonary blastoma is a rare malignant primary lung neoplasm typically seen in adults that accounts for 0.3-1.3% of lung malignancies. It has been categorized as a subtype of sarcomatoid carcinoma according to the current World Health Organization Classification of Lung Tumours and is distinct from the more common pediatric lung tumor pleuropulmonary blastoma. We report a case of neonatal pulmonary blastoma, illustrating the imaging characteristics of this rare tumor. The subject of pediatric lung masses is confusing because the terms pleuropulmonary blastoma and pulmonary blastoma have been used interchangeably in previously reported cases. We recommend use of the current WHO classification to differentiate these lesions as additional cases are described. Additionally, we discuss distinctive cytogenetic features of this case.