Ultrastructural and morphometric features of poorly differentiated and undifferentiated lung tumors.

Initial results are reported from a study of lung carcinomas and carcinoid tumors performed with electron microscopy and morphometric analysis of electron micrographs. The ultrastructural findings are being used to define the range of ultrastructures of the different tumor categories diagnosed by light microscopy using the revised World Health Organization classification. Morphometric data reveal a considerable degree of overlap in cell and nuclear size among different lung tumor types.