Correlation between lymph node micrometastasis and histologic classification of small lung adenocarcinomas, in considering the indication of limited surgery.

The validity of limited surgery for lung carcinomas have not been clearly established. Several reports suggest that not only tumor size but also the histological findings may be of importance in this role. By conducting immunohistochemical examinations of lymph node micrometastases from small lung adenocarcinomas, we considered the suitability of limited surgery for especially localized bronchioloalveolar carcinoma (LBAC) without active fibroblastic proliferation (Noguchi's histologic classification types A and B). In this study, we enrolled 54 patients with lung adenocarcinoma smaller than 2 cm in diameter. Lymph node involvement was demonstrated in 11 (20.4%) patients. Lymph node micrometastasis was present in 11 (25.6%) of the 43 patients at pN0 disease. However, 13 patients with LBAC without active fibroblastic proliferation (types A and B) had neither lymph node involvement nor micrometastasis. Our results indicate that limited pulmonary resection may be acceptable procedure for LBAC without active fibroblastic proliferation.