title: Divergent differentiative histogenetic lines in lung tumors: identification of histotypes with pure or mixed ultrastructural phenotype and their prognostic significance.
abstract: We performed an electron microscopic study of 50 lung tumors, previously diagnosed by light microscopy, and compared the results of the two techniques. Data analysis identified two ultrastructural phenotypes: pure and mixed. The former was characterized by a constant differentiative pattern and the latter by diverging differentiative histogenetic lines. We observed six differentiative lines as follows: squamous, glandular, neuroendocrine, villopodial, intestinal, and apocrine sudoriparous. Features of divergent differentiative lines were observed in 36 cases (64%), throughout the histotypes, sometimes with coexpression of more than one differentiation in a single case and/or cell. Adenocarcinoma was the histotype most frequently observed in pure form whereas most squamous cell carcinomas showed a mixed phenotype. This suggests that the histotype of the different lung tumors arises from a single glandular pluripotent cell, able to differentiate toward divergent differentiative lines. The clinical stage at onset and at the end of the follow-up indicates that the biologic behavior of lung tumors varies according to whether the ultrastructural phenotype is pure or mixed.
authors.affiliation: Department of Pathology, San Raffaele Hospital, University of Milan, Italy.
authors.forename: G L
authors.initials: GL
authors.lastname: Taccagni
authors.forename: E
authors.initials: E
authors.lastname: Rovere
authors.forename: M R
authors.initials: MR
authors.lastname: Terreni
authors.forename: S
authors.initials: S
authors.lastname: Gambini
authors.forename: A
authors.initials: A
authors.lastname: Cantaboni
mesh_terms: D000230:Adenocarcinoma / Q000145:classification / Q000648:ultrastructure*; D000328:Adult; D000368:Aged; D002276:Carcinoid Tumor / Q000145:classification / Q000648:ultrastructure; D018288:Carcinoma, Small Cell / Q000145:classification / Q000648:ultrastructure; D002294:Carcinoma, Squamous Cell / Q000145:classification / Q000648:ultrastructure; D002454:Cell Differentiation; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D010641:Phenotype; D011379:Prognosis