Histogenesis of adenosquamous bronchogenic carcinoma.

In our hamster lung cancer model studies, among 463 non-small-cell lung cancers (NSCLC), there were 47 adenosquamous neoplasms. In 24 of 27 lesions with diameters of less than 3.0 mm, the adenocarcinoma and the squamous cell carcinoma components arose as separate, spatially discrete lesions, but these were separate in only 7 of 20 lesions with diameters of 30 mm or greater. Co-infiltration of the components became more frequent as tumor size increased. The usual adenosquamous variety of NSCLC is likely a collision tumor, with each component possessing separate biological characteristics. Thus, future prognostically directed studies of this variety of NSCLC must recognize that these neoplasms have two components, each of which needs to assessed.