Primary pulmonary collision cancer consisting of large cell carcinoma and adenocarcinoma.

A case of pulmonary collision tumor is herein reported. An abnormal shadow was discovered in the right lung of a 53-year-old man. A right upper lobectomy with a mediastinal lymph node dissection was performed. Based on the findings of a postoperative pathologic examination, this tumor was considered to be a collision tumor of large cell carcinoma and adenocarcinoma, as the distribution of each tumor was clearly separated. This case is the first report of a primary pulmonary collision tumor consisting of large cell carcinoma and adenocarcinoma.