PURPOSE: To study the factors that influence computed tomographic (CT)
visibility of early squamous cell carcinoma, which was defined as a l
esion confined to the bronchial wall without lymph node metastasis. MA
TERIALS AND METHODS: CT was performed in 18 patients with 18 early squ
amous cell carcinoma lesions. The 5.0-mm or thinner sections were revi
ewed independently by three observers who were aware of the bronchosco
pic findings, and the visibility of the lesions was correlated with hi
stopathologic findings. RESULTS: Tumors consisted of 13 flat and five
polypoid lesions. Three of the lesions were epithelial, eight were sub
epithelial, and seven were cartilaginous or extracartilaginous. Eleven
lesions were visualized at CT as an endobronchial mass or focal bronc
hial wall thickening. Lesions with polypoid growth and/or cartilaginou
s or extracartilaginous invasion were all visualized, even on 5-mm-thi
ck sections. Subepithelial lesions could be demonstrated when located
at bronchi with craniocaudal orientation. CONCLUSION: CT is a valuable
tool for diagnosis of early squamous cell carcinomas, particularly wh
en lesions show polypoid growth and/or invade the cartilaginous layer.