Morphology of bronchial epithelium adjacent to adenocarcinoma of the lung.

Gross unremarkable bronchi and bronchioles from 22 lobectomy specimens containing primary adenocarcinoma were examined microscopically. Sections were taken from the segment containing the carcinoma and compared with sections taken from uninvolved segments in the same specimen to examine for premalignant lesions. The average tumor size was 3.75 cm (1.5 to 11 cm). The average age of patients was 60.4 yr (29 to 79 yr); 13 were men and nine were women; all were smokers, and the average was 44.1 pack-years (20 to 100 pack-years). Six of the specimens (27%) showed no histologic changes. Focal squamous metaplasia was identified in nine specimens (41%), but in four of the nine (44%), it was not seen in the carcinogenic segment. Focal goblet cell metaplasia was seen in six specimens (27%), but in two of the six (33%), it was not in the carcinogenic segment. Focal basal cell hyperplasia was seen in two specimens (9%) within both the carcinogenic segment and elsewhere. A single focus of mild epithelial dysplasia was found in each of two specimens (9%), but these foci were not in the carcinogenic segment. Focal epithelial regeneration was noted in three specimens (14%), but two of these (66) were not in the carcinogenic segment. Such microscopic abnormalities of respiratory epithelium are associated with cigarette smoking, and each is a potentially premalignant change; however, our study demonstrated no histologically identifiable changes in the respiratory epithelium that consistently mark for premalignant atypia in the lung adenocarcinoma.