title: Pulmonary blastoma: an ultrastructural and histochemical study.
abstract: We present a unique case of pulmonary blastoma and describe its histology and ultrastructure. The stromal component exhibited bizarre multinucleated giant cells containing previously undescribed granules. These membrane-limited granules were eosinophilic, periodic acid-Schiff positive, diastase resistant, acid phosphatase and nonspecific esterase negative, immunohistologically negative for lysozyme, albumin, and gamma globulin, and often homogeneously electron dense. A similar electron-dense material accumulated in the rough endoplasmic reticulum of these stromal giant cells, suggesting that the material in the granules is synthetic. The material appeared to be a glycoprotein but was not alpha1-antitrypsin, alpha-fetoprotein, or human chorionic gonadotropin by immunohistologic techniques. These stromal cell granules differ from granules described in epithelial cells of other pulmonary blastomas but resemble granules found in some sarcomas.
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure*; D006651:Histocytochemistry; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure*; D008297:Male; D008875:Middle Aged