Abstract
Nineteen cases of Squamous cell carcinoma in the periphery of the lung were examined cytologically and histologically. Their roentgenological findings were also analyzed. From the cytological and histological characteristics, they were classified into the following four types: 1) keratotic cell type, 2) basal cell type, 3) large cell type, and 4) small cell type.
Keratotic cell and basal cell types showed a clear tumor boundary with broad and shallow notches. Small cell types had many deep notches and were not surrounded by rough cord-shaped shadows. Since tumors of the large cell type had ill-defined tumor edges and rarely showed large notches, the chest X-ray shadows showed much variety. In terms of hematogenous metastasis, large cell and small cell carcinoma seem to be more malignant than keratotic cell and basal cell types. The histogenesis and growth process of these four types and the pattern of necrosis and fibrosis were also discussed.
