title: Pulmonary blastoma.
abstract: Two cases of pulmonary blastoma are reported. One occurred in a 29-year-old man 31 months after a cyst had been excised from the same pericardial-pleural area. The cyst appeared to be of mesothelial origin and, although supported by a cellular stroma, was originally considered to be benign. The morphologic features, location, and possible relationship to a mesothelial lesion suggest an embryonal-mesothelial origin of the tumor. The patient died of recurrent and metastatic disease 9 years after the first resection. The second case is that of a now 74-year-old woman who, over a period of 19 years, has had six separate small peripheral lung tumors excised. They originally resembled fibrous hamartomas but included embryonal-type immature areas and became increasingly more cellular and sarcomatous. The fine structure of the recurrent tumors is that of primitive stroma with few fibrils but no other differentiating features.
mesh_terms: D000328:Adult; D003560:Cysts / Q000473:pathology; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology; D008171:Lung Diseases / Q000473:pathology; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis