[Endobronchial ultrasonography for lung cancer]

We assessed the usefulness of endobronchial ultrasonography in the diagnosis of lung cancer. We performed a needle-puncture experiment on 45 normal tissue specimens to determine the luminar structure of the tracheobronchial wall. In addition, we compared the ultrasonographic determination of tumor invasion in 24 lung cancer patients with the histopathological findings. The cartilaginous portions of the extrapulmonary bronchi and the intrapulmonary bronchi exhibited a five-layered structure. Starting on the lumen side, the first layer (hyperechoic) was a marginal echo, the second (hypoechoic) was the submucosal tissue, the third (hyperechoic) was the marginal echo on the inner side of the bronchial cartilage, the fourth (hypoechoic) was bronchial cartilage, and the fifth (hyperechoic) was the marginal echo on the outer side of the cartilage. In the membranous portions, the first layer (hyperechoic) was a marginal echo, the second (hypoechoic) was smooth muscle, and the third (hyperechoic) corresponded to the adventitia. Comparisons between the ultrasonograms and the histopathological findings in 24 lung cancer patients revealed that depth diagnosis was the same in 23 lesions (95.8%) and different in 1 lesion (4.2%). We describe the usefulness of endobronchial ultrasonography in the diagnosis of peribronchial lymph nodes and peripheral pulmonary lesions.