A case of small peripheral lung adenocarcinoma with remarkable invasion of bronchial submucosal lymph ducts

A 52-year-old man was found to have a small adenocarcinoma of the right upper lobe of the lung, based on X-ray findings and TV-brushing. The clinical stage was IA, and he was referred to the surgical department for operation. Preoperative bronchofiberscopy showed mucosal redness and edema from the carina both to the bifurcation of the right upper lobe bronchus and the truncus intermedius and to the bifurcation of the left upper and the lower lobe bronchi. Bronchial biopsy showed remarkable submucosal lymph duct invasion of carcinoma cells. Therefore we concluded that there was no indication of surgery. We evaluated the E-cadherin-associated ceil-to-cell adhesion based on the immunohistochemical expression of E-cadherin and three kinds of undercoat proteins (alphacatenin, beta-catenin and plakoglobin). All undercoat proteins lost their normal expression. The results suggested that this case was the E-cadherin dysfunctional type. The TV-brushing specimen showed many solitary carcinoma cells. Clusters displayed a slight tendency to overlap, with poor cellular adherence. It is necessary to carefully investigate the bronchofiberscopic findings even in small peripheral adenocarcinomas.