Metastatic squamous cell carcinoma of the mediastinum with unknown primary tumor.

Although metastatic carcinoma from an unknown primary tumor is known to occur, the combination of squamous cell carcinoma histologic findings and a mediastinal location is quite unusual. The evaluation of a case of a patient with a posterior mediastinal mass, eventually shown to be metastatic squamous cell carcinoma of the mediastinum with unknown primary tumor, is described herein. Resection of the lymph node mass was performed and was followed by chemoradiation for presumed lung cancer.