title: Bronchiolo-alveolar carcinoma-cell of origin.
abstract: Bronchiolo-alveolar carcinoma is the least common of the primary pulmonary carcinomas, and there is controversy as to its cell of origin. In this light- and electron microscopic study of five bronchiolo-alveolar carcinomas, at least two cell types were found, both of bronchiolar origin. One cell type is a metaplastic bronchiolar mucous cell and the other a bronchiolar stem cell that has ultrastructural features of both the respiratory ciliated and the respiratory nonciliated ("Clara") cell. It would not be unusual if tumors of the bronchiolo-alveolar region differentiate into cells of either the bronchiole or the alveolus, for embryologically they have a common origin. However, as information about the ultrastructure of these tumors accumulates, it is becoming apparent that an alveolar-cell carcinoma must be a rare occurrence. Hyperplastic Type II aleveolar epithelial cells may be found about the margins of these tumors and can be mistaken for the neoplastic cells.
mesh_terms: D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000473:pathology*; D000368:Aged; D002462:Cell Membrane / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D003896:Desmosomes / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000648:ultrastructure; D005260:Female; D006801:Humans; D002479:Inclusion Bodies / Q000648:ultrastructure; D007365:Intercellular Junctions / Q000648:ultrastructure; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000648:ultrastructure; D009077:Mucins; D014617:Vacuoles / Q000648:ultrastructure
chemical_list: D009077:Mucins