Pulmonary blastoma (PB) is a biphasic primary lung neoplasm, belonging to the group of sarcomatoid lung carcinomas (SLCs; see this term). The tumor contains both an epithelial well-differentiated component, showing tubular architecture resembling the normal fetal lung, and a mesenchymal undifferentiated stroma with a so-called ''blastema-like'' configuration that resembles an embryonic lung.