Lung adenocarcinomas with micropapillary components

Purpose: Micropapillary adenocarcinoma is becoming increasingly recognized as a prognostically important histological subtype of carcinoma in various organs. This report presents the clinicopathological findings of lung adenocarcinomas with micropapillary components. Methods: A total of 15 patients with micropapillary components were selected between April 2005 and December 2008. The results of their clinical presentation, metastasis to lymph nodes, pleural invasion, pathological stage, and clinical outcomes were evaluated. Results: In all, 12 patients underwent a lobectomy or bilobectomy with a regional lymph node dissection; 8 showed metastases to the regional lymph nodes at the time of the operation. Altogether, 14 of 15 cases showed lymphovascular invasion; 10 cases were up-staged after the operation because of lymph node metastases or pleural invasion. The duration of follow-up ranged from 1 to 42 months (median 16 months). Seven patients are alive without disease, whereas seven are alive with disease and one patient died of disease. Conclusion: These results suggest that the micropapillary components are a manifestation of aggressive behavior, as shown by the frequent lymph node metastases and pleural invasion. Surgeons should search more carefully for metastases and conduct a closer follow-up on these patients when this feature is present with lung adenocarcinoma. © 2009 The Japanese Association for Thoracic Surgery.