Combined carcinoid tumor of the lung: a combination of carcinoid and adenocarcinoma.

Combined small cell carcinoma is an uncommon but well described diagnostic category of neuroendocrine lung tumors. The prognosis of these tumors appears to be similar to that of pure small cell carcinoma, although it is believed that the non-small cell components of these tumors are less chemo-responsive than the small cell components. We report a case of a 60-year-old male smoker with a 2-cm nodule that, on subsequent lobectomy, was a combination of carcinoid and adenocarcinoma. A lymph node metastasis to an ipsilateral hilar node was comprised of only the well differentiated adenocarcinoma component. The biologic behavior of such tumors is not well described and their place within, what may be described as, a spectrum of combined neuroendocrine tumors is discussed.