Pulmonary collision tumor consisting of adenocarcinoma and typical carcinoid--a case report and review of literature.

Collision tumors are rare in nature. We report a case of a 70-year-old woman who was found to have a new mass in the right lung. Right upper and middle lobectomies with a mediastinal lymph node sampling were performed. Pathological examination of the mass revealed a collision tumor composed of micropapillary adenocarcinoma and typical carcinoid. The neoplastic cells were not intimately admixed with one another. To the best of our knowledge, this case is the first report in the English medical literature of a primary pulmonary collision tumor consisting of micropapillary adenocarcinoma and typical carcinoid.