Case Report: 84-Month Disease-Free Survival after Surgery for Anaplastic Thyroid Carcinoma.

We present a rare case of a patient with anaplastic thyroid carcinoma (ATC) who survived for 87 months after surgery. The patient was a 71-year-old man who presented with a painful enlarged mass in the right side of his neck that rapidly enlarged over 2 months. He was diagnosed with T4a, stage IVA ATC with no distant metastasis and underwent total thyroidectomy with modified neck dissection. Although only radiation and radioactive iodine therapy were administered after surgery, he remained disease-free for 84 months. Bone metastasis occurred after 84 months, and he was treated with Lenvatinib, but he died from a decline in his general condition 3 months later. We suggest that surgery is effective for stage IVA ATC, but adjuvant therapy is necessary for long-term disease-free survival in this patient population.