Thyroid metastasis from non-small cell lung cancer

Non-thyroid malignancies to the thyroid gland resulting from distant metastases are extremely rare, and such cases are rarely seen in clinical settings. The question of how a tumor metastasizes to the thyroid remains unanswered. Here we report a case of lung adenocarcinoma metastasizing to the thyroid gland. The article covers the pathological features, treatments, examination reports, and the postoperative follow-up reviews of the patient. In this article, we discuss the diagnostic method, the spread route, the prognosis, the mechanism and above all, the treatment. In addition, we searched the PubMed and ISI Web of Science databases for articles published in English using the key words "lung", "thyroid", and "metastasis", and we reviewed nearly all the reports about thyroid malignancies being metastasized from lung cancer. This rare case emphasizes the importance of the multifaceted comprehensiveness of the cephalometry diagnosis, pathological diagnosis, and immunohistochemical analysis to ensure that such rare cases are not missed. We declare that all cases of thyroid malignancies metastasized from the lungs shall be reported at large for further clinical research.