Thyroid metastasis revealing a primary lung cancer is an extremely rare condition. Only few cases have been reported in the literature. A multidisciplinary approach is essential for the diagnosis. The prognosis is generally poor. We report a case of a 50-year-old man presented with cervical nodules corresponding to a thyroid nodule and lymph nodes. The ultrasonography-guided fine-needle aspiration cytology of the thyroid nodule and a cervical lymphadenopathy concluded to a poorly differentiated adenocarcinoma. Cervical lymphadenopathy biopsy with immunohistochemistry and additional imaging explorations contributed to the diagnosis of a lung adenocarcinoma stage IVB. He died few days after the diagnosis.