Histogenesis of the papillary Clara cell adenoma.

摘要: Abstract Mouse lung adenomas have two characteristic histologic patterns, alveolar and bronchiolar or papillary. Differences in biologic behavior been noted tumors of different form, that papillary were said to grow faster become larger possibly malignant. Progressive development from the has proposed, involving a step-wise transformation benign malignant tumors. The author recently presented evidence ultrastructural studies patterns related cell origin; consisted Clara cells, while made up Type II epithelium. In present study, designed evaluate during their development, multiple induced fetal Bagg-Webster mice on sixteenth day gestation by single transplacental exposure ethyl-nitrosourea. animals killed seventh postnatal 185 days age; counted categorized histologically. Analysis serial-step sections right lower lobes young showed with either an (37%) pattern (63%). Two forms latter recognized, tubular Between Day 80 186 increased, decreased, remained relatively constant number. At end 6-month observation period overall proportion was similar found first 3 weeks life. These data support concept arise lines, exclusively cells.