Bronchoscopic findings of extramural lung cancer invading the subepithelium or submucosa

Bronchoscopic findings from the main to segmental bronchi were compared with the histopathological findings in 185 resected cases of lung cancer, in order to determine which bronchoscopic features are associated with lung cancer invading the subepithelium or submucosa from beyond the bronchial wall. Carcinoma invaded the subepithelium or submucosa from beyond the bronchial wall in 43 cases (22.9%) out of the total of 185 cases. Bronchoscopic findings were evaluated in these 43 cases, and were summarized as follows: (1) The bronchoscopic findings in cases of subepithelial invasion consisted of vascular engorgement, bleeding, subepithelial tumor, and emphasized longitudinal relief; (2) irregularity of the mucosa was observed in cases of epithelial or muscular invasion; (3) indistinct bronchial cartilage was observed in cases of invasion proximal to the extramuscular layer; (4) accentuated irregular folds were observed in cases of invasion of the extramuscular or cartilage layers; and (5) edema and redness were not specific for malignancy. In addition, the occurrence of mediastinal lymph node metastasis was higher in cases of invasion to main or lobar bronchi. This result indicates that recognition of invasion of the subepithelium or submucosa of the central bronchus may be helpful in indicating the probability of mediastinal lymph node metastasis. Accordingly, there may be specific bronchoscopic findings which correlate with invasion of the bronchial subepithelium or submucosa. Accurate recognition of these findings may be useful in determining appropriate biopsy sites and may provide more information concerning selection of therapeutic strategy.