Abstract
Since 1978, twenty nine cases of early stage hilar lung cancer were resected in our hospital. Out of them, 14 cases were diagnosed as the superficial infiltrating type of squamous cell carcinoma. A total of 17 superficial cancer lesions were studied bronchoscopically and histopathologically. In 13 sites, the cancers were limited to within the intraepithelial layer or subepithelial layer, and in 4 sites they extended beyond the smooth muscle layer. In both pathological conditions, the mucosal surfaces showed loss of normal luster were pale in color and revealed fine granular changes. Thickened and friable bronchial bifurcations were also recognized in all cases. In areas where tumors invaded beyond the smooth muscle, the mucosal surfaces showed coarse granular changes and interruption or loss of longitudinal folds. Although squamous metaplasia, closely resembling intraepithelial carcinoma bronchoscopically showed thickening and hardening of the spur, the same irregularity of the mucosal surface was not observed nor was the friability observed in intraepithelial carcinoma recognized in the former. We would like to emphasize that these difference between intraepithelial cancer and squamous metaplasia are probably responsible for the histological findings in submucosal layers. That is, the infiltration of mononuclear cells and capillary proliferation occur significantly in early stage luno cancer, while increase in collagen fibers is frequently seen in squamous metaplasia.
