Thyroid papillary carcinoma generally has a favorable prognosis; however, we occasionally face high-risk cases with poor prognosis. Additional treatments such as radioactive iodine therapy and molecular targeted therapy are employed for these cases. We now present a case of a patient who received lenvatinib treatment for unresectable lesions. The patient was a 72-year-old man with thyroid papillary carcinoma (cT4aN1bM1) havingbilateral jugular vein involvements, ciricotracheal invasion, multiple mediastinal lymph node metastasis, and lung and sinonasal metastasis. The patient underwent total thyroidectomy combined with the right-sided neck dissection, including removal of the right jugular vein and skin invasion area. Tracheal and skin defects were reconstructed withthe right deltopectoral flap. Since the left cervical lymph nodes were infiltrating the internal jugular vein, left neck dissection was not performed to avoidsevere complications due to both jugular vein resections. Postoperatively, radioactive iodine (RAI) therapy was administered, but the patient did not have any improvement in residual lesions. Subsequently, radiation therapy was given for enlarging ethmoid and sphenoid sinus metastases. Treatment with lenvatinib was then initiated. During the course, intracranial hemorrhage occurred, which was judged to be an adverse event of lenvatinib, leading to a temporary discontinuation of the drug. After stabilizing the blood pressure, lenvatinib was resumed at a reduced dose. Four years post-surgery, with continued lenvatinib therapy, both local and distant tumors have disappeared, and the patient has maintained remission.