Abstract
BACKGROUND: Thyroid metastasis of soft tissue sarcoma is very rare, and the diagnosis is especially difficult when only a single lesion is present. CASE PRESENTATION: A 50-year-old man was diagnosed with myxoid liposarcoma of the right thigh and treated with wide resection. Two and a half years after the surgery, a growing low-density area was incidentally observed in the right lobe of his thyroid gland on follow-up chest computed tomography. Fine needle aspiration biopsy was performed twice, and the thyroid mass was suspected of being a sarcoma metastasis. He was treated by hemithyroidectomy, and the lesion was pathologically confirmed as a metastasis of myxoid liposarcoma. CONCLUSION: We experienced single thyroid gland metastasis in patients with myxoid liposarcoma in whom a growing mass is observed in the thyroid gland after radical surgery of the primary site.