Thin slice CT of lung tumors

Thin slice (2 mm) CT (CT) findings of peripheral portions of 22 solitary lung tumors (37 portions) were reviewed in comparison with pathohistologic findings. A poorly defined tumor-edge with reticular pattern on CT was found only in moderately or well differentiated adenocarcinoma and it corresponded pathohistologically to superficial tumor-cells replacement of alveolar cells without alveolar collapse. In tumors with CT findings of comparatively defined tumor-edge with linear or strand projection, tumor cells replaced alveolar cells showing alveolar collapse with slight or marked interstitial fibrosis. Especially, a linear projection finding on CT may indicate an early phase in contracting process. Invasion of cancer cells along both bronchiole and small vessels was often found in the portion corresponding to the strand projection finding on CT which indicated poorer prognosis. Comparatively defined tumor-edge with serrated projection and sharply defined tumor-edge on CT images, both of which were found mainly in tumors with cell types of poorly differentiated adenocarcinoma, squamous cell carcinoma, and undifferentiated carcinoma, showed histo-pathologically tumor-cells replacement of alveolar cavities with thickened alveolar septa and with displaced alveolar septa, respectively. A cavity-like low density area on CT which was found in adenocarcinoma was pathohistologically dilated bronchiole. Thin slice CT is useful for evaluation of the extent and growth of a tumor. (author)