Comparison of the Electron Microscopic Findings of Advanced and Early Stage Squamous Cell Carcinoma of the Lung

Abstract

Twenty three resected central type advanced cases of squamous cell carcinoma of the lung were observed by light and electron microscopy, and the findings were compared with early stage cases. Examination of the tumor cells in the basal layer in terms of electron density of the cytoplasm, intercellular spaces and degree of development of cytoplasmic processes showed a variety of cells ranging from Type I, where the cytoplasm was dark, with well-developed cytoplasmic processes large intercellular spaces, to Type IV, where cytoplasmic processes and intercellular spaces were poorly developed and the cells were mostly of the clear cell type. In advanced cases, all four cell types were recognized, but in early stage cases, only Type I-III cells were recognized. Furthermore, in advanced cases, Type III cells were more frequently found, and both the nuclear area and mitotic rate were greater than in early cases.