Multiple malignancies of the lung and head and neck. Second primary tumor or metastasis?

Independent primary cancers of the head and neck and of the lung may be confused with lung metastases from a head and neck tumor. We retrospectively reviewed the cases of 55 patients who had head and neck malignancies and pulmonary lesions. To distinguish between independent primary tumors and lung metastases we applied an algorithm using the following criteria: sequence of appearance of the lesions; tumor histology; radiologic appearance of the lesions; and presence of malignant anterior cervical adenopathy. In this group of 55 patients, 40 were categorized as having independent primary malignancies and 15 were categorized as having pulmonary metastases from the head and neck tumor. In cases in which the origin of the pulmonary lesion is unclear, the patient should be treated as though independent primary malignancies were present since this offers the best chance for cure.