Electron Microscopic Observation of Early Stage Squamous Cell Carcinoma of the Lung

Abstract

Seventeen resected cases of early squamous cell carcinoma of the lung were studied by electron microscopy and the following results were obtained. 1) The 17 cases had no acinar differentiation and were classified on the basis of the electron microscopic appearance of tumor cells in the basal layer as follows. Type I is a tumor in which the cells have prominent cytoplasmic processes, wide intercellular spaces, dark cytoplasm, many desmosomes (Ds) and tonofilaments (Tf) (5 cases). Type III is a tumor in which the cells have relatively clear cytoplasm with some cytoplasmic processes and some intercellular spaces (7 cases). Type II is an intermediate type between type I and type III (5 cases). 2) These cell types had good correlation with the pattern of invasion, depth of invasion, dissolution of basement membrane, mitotic count and cellular atypia. 3) Three cases had many small dense core granules.